Technical Discussion 9/30 Afternoon Shift

Another pattern of clear, sunny skies and above-average temperatures appears to be in store for the week ahead. A look at the weekend, however, appears to show some wetter weather on its way.

Short Term (Mon-Wed)
A mix of sun and clouds Monday sets the tone for the week ahead. A weak cold front ahead of a weak trough may bring some clouds to the western portions of the state Monday evening heading into Tuesday, but this front will likely dissipate. High pressure-air then takes over for the majority of the week ahead. Temperatures are predicted to climb into the mid-70s for most of Pennsylvania. The urban heat island effects around Pittsburgh and Philadelphia will cause temperatures in the southern corners of Pennsylvania to reach the low-to-mid-80s.

Long Term (Wed-Fri)
A pattern of warm, low humidity air looks to hold its ground for the latter portion of the week. As Friday approaches, however, a high pressure system over the southeastern US looks to change this. Circulation around the high appears to send some moist air from the Gulf of Mexico up to Pennsylvania, which could create some cloudier and wetter conditions. Clouds and rain can be expected for Friday, and are possible throughout the weekend ahead as well. Temperatures are expected to cool down a bit with the arrival of this moist air as well.

Monday Morning Technical Discussion

Synopsis

Another week of dry, mostly sunny weather awaits the Commonwealth.  With the exception of a weak disturbance that could bring showers to western half of the state, mostly sunny skies and temperatures steadily rising from the high 60s to low 80s will affect Pennsylvania throughout the week.   A weak warm front will move through the region on Friday, bringing with it a chance of showers, but significant precipitation is not expected until the passage of a cold front on Sunday.

Short-Term (Through 0z Thursday)

Both the GFS and NAM agree that mostly sunny skies and temperatures in the high-60s and low-70s will affect the state on Monday.  Though both models are indicating cloudier conditions on Tuesday due to a low pressure system passing to the north, only the NAM (particularly 06z Hi-Res NAM) is indicating showers for the western half of the state.  Temperatures will be mostly in the 70s on Wednesday, with skies clearing once again.

Long-Term (Past 0z Thursday)

Thursday and Friday will again see generally clear skies and temperatures in the high 70s and low 80s.  A weak warm front is predicted by the GFS to pass through the state Friday evening, but little rainfall is associated with this front.  Skies will begin to cloud on Saturday as a result of an incoming cold front, which is predicted to pass through the state on Sunday, bringing with it widespread showers and more seasonally cool air.

 

~Patrick Higgins

Friday PM Technical Discussion

Synopsis:

With the exception of a cold front approaching from the west and a coastal system expected to remain well off-shore, the next six days will be relatively quiet across the Commonwealth. Clear skies, light winds, warm days and cool nights greet the end of September & start of October.

Models Used: 12z GFS, 12z ECMWF, 9z & 15z SREF, 12z NAM, and 12z Hi-Res NAM

Models are in general agreement with the overall synoptic pattern this week & precipitation probabilities for Sunday Night & Monday, with the SREFs best handling the precip. timing since only a few hundredths are expected to fall over the Allegheny Plateau on Monday, which are not being picked up by the deterministic models (NAM & Hi-Res NAM). Most of the rain (around a tenth-inch) will occur in Erie and Crawford counties Sunday night into Monday morning, and the coastal system will only affect coastal states.

-Jaron

Tuesday Night Technical Discussion

Synopsis:

High pressure will build over the region for the remainder of the week into the first half of the weekend providing pleasant fall weather with cool nights and normal high temperatures. A coastal low could possibly threaten the far eastern portions of the state with scattered showers on Sunday into Monday, and a cold front from the west will make its way across the region bringing scattered showers Monday evening into early Tuesday.

 

Short Term (Tuesday night through Wednesday night):

Calm winds at night and clear skies will provide cool temperatures in the low to mid 30's for higher elevations allowing for some widespread frost to form Tuesday Night. Also expect fog to form Wednesday and Thursday morning as temperatures cool to their dew points. Wednesday will be another day of beautiful fall weather after a cool night as high pressure sits over PA. Temperatures are likely to reach the low to mid 70's in southern counties of the state and mid to upper 60's elsewhere Wednesday indicated by the 18Z 12km NAM.

 

Long Term (Thursday into the weekend):

High pressure will continue to sit over the state Thursday through Saturday providing more pleasant weather with clear skies and calm winds. A coastal low will attempt to throw some moisture towards eastern portions of PA late Sunday into Monday but the 18Z GFS is not showing a chance of it reaching the state. A slow moving cold front will finally make its way across the state Monday into Tuesday bringing some wide spread showers as the long-lived ridge of high pressure finally moves off the coast.

 

~ A.J. Herbert

Forecast Discussion 9/23 Afternoon Shift

A cold front has left temperatures in Pennsylvania cool and autumn-like, and high pressure is set to take over and create very pleasant and sunny conditions for the week ahead.

Short term (Mon-Wed)

Cloudy skies Monday morning have dissipated thanks to a high-pressure ridge moving into Pennsylvania. This high-pressure ridge will bring very little moisture content with it, setting up for low humidity with little to no cloud cover. The absence of clouds will allow for temperatures to steadily climb through the 70s heading later into the week. Low temperatures overnight will be in the low 40s and possibly the 30s for the northern portions of the state, so frost is a possibility.

Long term (Wed-Fri)

Sunny skies will persist through Wednesday. A trough extending down from Canada will begin to make its way east, but will most likely weaken and dissipate when matched against the ridge currently over Pennsylvania, and any low-pressure air will be diverted south, leaving the same weather pattern in place through the weekend. Temperatures will be a bit warmer for September, reaching the mid-70s in most areas of the state, with overnight lows in the 40s.

Monday Morning Technical Discussion

Synopsis

Following Saturday's slow-moving cold front, high pressure will continue to build into the Commonwealth, leading to mostly sunny skies and temperatures in the 60s and low 70s for most of the state.  Some areas may experience patchy frost, particularly Bradford, as low temperatures will often reach down into the 30s and 40s.  Additionally, dew points will be very comfortable, ranging from the low 30s to low 40s.  High pressure will remain entrenched in the region throughout the week, with the only threat of precipitation coming on late Sunday afternoon. 

Short-Term (Through 0z Friday)

Both the GFS and NAM agree that skies will be generally clear and temperatures will rise through the 60s on Monday and Tuesday before plateauing in the low- to mid-70s for Wednesday, Thursday, and Friday.  At times, clouds will pop up overnight, limiting the downward reach of the low temperatures, but models generally agree that most lows will be in the 40s.

Long-Term (Beyond 0z Friday)

The NAM's forecast period ends with temperatures still hanging in the 70s and skies remaining clear.  Over the week, the GFS is indicating that another cold front will pass through the region, bringing with it precipitation and another cool down for next week. 

~Patrick Higgins

Tuesday Night Discussion

Synopsis:

High pressure will continue to build over the state and clear skies and dry conditions will follow. High temperatures will rise throughout the week until a cold front slowly moves across the region Saturday into Sunday morning bringing widespread showers throughout the weekend.

 

Short Term: (Tuesday night through Wednesday night)

As a ridge of high pressure continues to build over PA, comfortable conditions and clear skies will persist. Each day the high temperature will increase owing to the clear skies and lack of any other negative influence on temperature. High temperatures look to reach the upper 70's across the entire state by Friday indicated by the 18Z 12km NAM, with low 80's possible in southwestern counties. Clear skies and calm conditions at night will allow for significant radiative cooling throughout the week with higher elevations reaching the mid 30's Tuesday night. As the high pressure moves off the coast Friday and the low pressure begins to approach the area, a southwesterly flow will develop and help increase the temperatures through advection for the day, along with some moisture advection to provide a few more clouds. A cold front, associated with a low-pressure system in the Northwest progresses east throughout the week.

 

Long Term: (Thursday into the Weekend)

The high pressure that builds over the region throughout the week helps strengthen the low-pressure system to our northwest, which eventually moves northeast into Canada, as the ridge slowly moves off the coast early Friday morning. The low-pressure system looks to eventually become a cutoff low late Friday night indicated by the 18Z GFS. As the warm front associated with the system to the north becomes stagnant Friday afternoon, scattered showers are possible for western portions of the state. Otherwise, the majority of the precipitation will fall between Saturday afternoon and early Sunday morning as the cold front moves across the state. In the wake of the cold front high pressure will once again build over PA for the beginning of the workweek providing slightly lower temperatures attributed to a rather shallow trough.

 

~ A.J. Herbert

Forecast Discussion 9/16/13 Afternoon Shift

A very pleasant week is in store for the commonwealth, with seasonable temperatures and sun lasting until later in the week. A low pressure system lurks north of the border, ready to drag a trough bringing showers and thunderstorms through Pennsylvania.

Short Term (Mon-Wed)

Showers Monday morning effectively drained the atmosphere of any moisture still present, setting up for a dry and sunny forecast for the next couple of days. A high pressure ridge looks to be taking the place of the trough from the previous weekend. Temperatures will steadily climb through the 70s across the state, while southern portions of Pennsylvania may be slightly warmer. Sun and possibly a few passing clouds are the story for the earlier portion of the week, so it looks to be a pleasant forecast.

Long Term (Wed-Fri)

Wednesday evening heading into Thursday sees a slight increase in the relative humidity in the lower levels of the atmosphere. A few clouds are possible throughout the day and night on Thursday for most of the state. Temperatures will reach their peak on Friday, with areas around Philadelphia and Pittsburgh reaching close to 80 degrees. Friday evening sees the progression of a cold front, bringing showers and possibly some strong thunderstorms for Friday heading into Saturday as well.

Monday Morning Technical Discussion

Synopsis

High pressure will dominate weather for the week as a cold front moves passed us. Bring high temperatures in the 60's and 70's to the area.

Short term

Rain possible early on Monday after that the skies clear as the high pressure builds in over the area. This will gives temperatures with highs in the mid to upper 60's and lows in the 40's.

Long term

The high pressure sticks with us and begins to move out at the end of the week giving the possibility of thunderstorms on Friday. This will cause the high temperatures to be in the low to mid 70's and low temperatures to increase to the 50's.

John Anthony (J.W.)

Synopsis:

After a weekend of fall-like temperatures, a weak front will pass through the commonwealth on Monday bringing clouds and a few showers to the majority of the state.  Temperatures will stay in the 60s on Monday as the sun will find trouble breaking the clouds.  Following the passing of the front, winds will turn northerly drawing cool air throughout the whole state on Monday night.  High pressure will then build across the Northeast associated with cool temperatures and sunny skies for the rest of the work week.

Short Term:

Both the 18z NAM and GFS show a weak disturbance crossing the state from Northwest to Southeast on Monday. Rainfall amounts associated with this precipitation will be minimal.  Most of Pennsylvania should expect cloudy skies and a few showers before the front passes.  Temperatures on Monday will hover in the upper 50s and 60s, with cooler temperatures in the Northwest regions of the State.  On Monday night, temperatures will dip into the 40s across the state, and as low as the mid-30s in northern areas of Pennsylvania. 

Long Term:

It will be an uneventful week of weather after Monday as high pressure will build over the Northeast.  Temperatures will hover in the Mid 60s across the state, with warmer temperatures by Thursday and Friday.  Night time temperatures will dip into the upper 30s and 40s for the majority of the state.  Expect sunny conditions and low humidity with dew points in the 40s.

Maximilian Vido

Friday Afternoon

Synopsis:

After the powerful series of cold fronts touched off severe thunderstorms yesterday, cooler weather is on tap for the weekend into early next week as high pressure will settle in. There will be a much weaker front passing through on Monday, which will touch off a few showers.

Models Used: 12z NAM, GFS, ECMWF, SREF; Hi-Res NAM not needed

All the models were all in agreement with the overall synoptic pattern over the next five days. High pressure will settle in overnight, clearing out the clouds and instability-driven, lake-enhanced showers. The high will move offshore Sunday AM and the southerly flow will advect in some warmer air. The GFS, NAM, & Euro each had the timing of this front for a wee hours to late afternoon passage (going from west to east). And high pressure will settle in for next week.

-Jaron Breen

Tuesday Night Technical Discussion

Synopsis:

 

In the wake of a high pressure moving off shore, a southerly flow is advecting warmer and moist air into the region. The unseasonably warm and humid air will remain until Thursday when a cold front will make its way across the state, bringing widespread rain showers. Cooler air will follow the passage of the cold front for the end of the week into the weekend.

 

Short Term: (Tuesday Night through Wednesday Night)

 

The southerly flow associated with the Bermuda high off shore will continue to bring warm and humid air into the region until Thursday. There will potentially be warmer temperatures nearing 90 degrees in many locations after a mild night Tuesday night compared to Monday night, as well as a chance for widespread scattered showers and storms tomorrow afternoon during max heating.

 

Long Term: (Thursday into the Weekend)

 

Both 18Z GFS and NAM are agreeing with the cold front to move into northwestern PA by 12Z Thursday and exiting the Philadelphia area around 03Z Friday. The 21Z SREF also agrees with the timing of this front and all three models agree with significant rainfall and scattered storms accompanying the frontal passage. The 18Z 12km NAM has some scattered showers across northwestern and northern PA associated with the mean northerly flow off the lakes. Cooler and drier air will follow this front and bring temperatures to a seasonable value with highs averaging in the 60's, as high pressure will build over the region for the end of the week into the weekend.

 

~ A.J. Herbert

Monday Evening Forecast

Synopsis:  Pennsylvania will be experiencing warmer temperatures early this week dying down into the 60s on Friday. The majority of days this week will see sun with a chance of rain on Wednesday and a chance for thunderstorms for much of the state on Thursday. Nothing truly exciting is currently happening around the nation except for heavy rains and flash flood warnings in the 4 Corners Region out West.

Outlook: Consistent southerly winds advecting moist, hot air will cause temps and dewpoints to spike well above average tomorrow and Wednesday. This circulation pattern will be associated with a developing low to the west that will move NE over the Great Lakes.  We won't see much in the way of storms from this system as its associated (and weak) fronts move through on Wednesday.  GFS shows it merging with another developing low in Ontario and strengthening as the combined low heads eastward.  The cold front associated with this system WILL impact PA on Thursday, bringing storms (some strong) in the early afternoon.  Afterwards, a NW flow sets up, bringing chilly temperatures with highs in the 60's across much of the commonwealth.

Forecast Discussion 9/9/13 Afternoon Shift

Much warmer temperatures are in store for Wednesday and Thursday, but a cold front is ready and waiting to bring some showers and thunderstorms, and return those temperatures to normal.

Short Term (Mon-Wed):

Cloudy skies Monday will clear up and then set the stage for summer-like temperatures. High temperatures across the state are expected to be in the high 80s, and low 90s around the more urban areas of the state. Skies will remain mostly clear for Tuesday. However, Wednesday sees the approach of a cold front extending down from a low pressure air mass over Canada.

Long Term (Wed-Fri):
Wednesday will bring scattered showers and thunderstorms to the state. Thunderstorms could grow stronger with the presence of high CAPE values in the lower levels of the atmosphere. Thursday brings a continuation of these showers and thunderstorms. Temperatures, however, drop into the high to mid-70s behind the advancing cold front. Friday is set up as a much more seasonable day, with temperatures in the mid-60s and clearer skies. This same pattern of clear, autumn-like weather appears to be the pattern heading into the weekend as well.

Monday Morning Technical Discussion

SYNOPSIS

High pressure will begin to move away from the region as a low pressure system moves through the Midwest.  Following the passage of the warm front on Tuesday afternoon, higher, summerlike temperatures will again affect the state.  Thunderstorms will be possible following this warm front, but the greatest convection will come on Thursday, when a cold front will pass through the region.  High pressure will surge back into the region on Friday and Saturday, bringing with it a return to autumnal temperatures.

Short-Term (Through 0z Thursday)

High pressure is expected to erode throughout the day on Monday as a low pressure system approaches from the west.  The 6z GFS moves the warm front through the region a bit quicker than the 6z NAM, but both models expect warm air advection to propel temperatures into the 80s across the state on Tuesday, with 90s possible in the Southeast.  Both models offer a chance of precipitation as the warm front passes, with the NAM expecting more precipitation, due to the later passage of the front and resulting increased chance of convection; precipitation is unlikely to be widespread, however.  Similar conditions will exist on Wednesday, with a chance of thunderstorms and summerlike temperatures in the 80s and low 90s.  Expect conditions to become stickier on Wednesday as well.

Long-Term (Beyond 0z Thursday)

Temperatures will remain in the 80s for most of the state on Thursday, but will be limited by a strong cold front that is expected to pass through the region in the afternoon and evening.  The GFS is delaying this cold front a bit more than the NAM, allowing for more heating and consequently more convection.  Following Thursday's potentially strong storms, high pressure will again fill into the region.  Clear skies and temperatures in the 60s and 70s can be expected throughout the state on Friday and into the weekend.

~Patrick Higgins

Sunday Night Technical Discussion

Synopsis

 

A warm front pushes upward across the state on Tuesday, creating a southerly flow. This front will cause temperatures to rise back into the mid-80s. The unseasonable temperatures will not last long however, as a cold front follows behind on Thursday. In between the fronts, we should expect to see some storms.

 

Short Term (through 12Z Tuesday)

 

The high pressure system lying over the state on Monday keeps the cool, dry conditions for the beginning of the week. Come midday on Tuesday, the direction of airflow switches direction as a warm front drapes north. We will see a return of the summer-like, humid air for the midweek.

Long Term (through 12Z Friday)

The warm temperatures continue through Tuesday and Wednesday. As a cold front approaches, there should be some storms throughout the state on Wednesday and possibly into Thursday. As the cold front passes, an air mass over Canada drops down into the state and drops temperatures back down. We get back into the comfortable fall-like conditions. Friday should be a pleasant day leading into the weekend.

-Joshua Gugel

Wednesday Night Technical Discussion

SYNOPSIS

A weak cold front will alter Thursday's weather pattern slightly, despite a relatively low risk of precipitation. This will set up for very cold overnight lows into early Friday. High pressure will define the weather picture heading into the first half of the weekend, while the next FROPA on Sunday could bring at least a small amount of rain to most of Pennsylvania.

SHORT-TERM (THROUGH 12Z FRIDAY)

A weak cold front is expected to slide into northern Pennsylvania early Thursday morning. 21z SREF shows the greatest chance of measurable precipitation just crossing the PA/NY border right around sunup on Thursday. Even at that, it seems like a long shot to see measurable precip at any station perhaps besides KBFD.  Temperatures will be moderated by the front on Thursday, though, with highs appearing to be capped in the low 70s across the state at best. Temperatures will also fall to very cold levels Thursday night into Friday morning, with lows dipping into the 30s in parts of Northern PA (GFS MOS gives KBFD a low of 29 Thursday night, while KUNV gets a still chilly 41). The risk of frost seems relatively low, but it will be a chilly start for almost everyone.

LONG-TERM (BEYOND 12Z FRIDAY)

The generally calm weather period continues through the first half of the upcoming weekend with high pressure sliding across the state on Friday and positioning itself off the Delmarva on Saturday. This will usher in some WAA for Saturday boosting temperatures back to the upper 70s across much of the state. The next rain maker, such that it is, enters the picture on early Sunday with a cold front stemming from a low way up in eastern Quebec. The 12z Euro keeps the rain risk around longer, while the 18z GFS seems to present the possibility of higher rainfall amounts. Another large ridge of high pressure along with rising heights should mean the start of next week is pleasant as well.

~Devin Boyer

Tuesday Night Technical Discussion

Synopsis:

 

As the cold front continues to move off the east coast, northwest flow and the associated high pressure will provide lower temperatures and drier air for the rest of the work-week. A weak cold front with little moisture will provide a chance of showers during the weekend before high pressure builds back in on Monday.

 

Short Term: (Tuesday Night through Wednesday Night)

 

Clouds will clear Tuesday night, as the upslope flow of warmer air off the lakes will die down with the winds. High pressure will begin to move into the state from the southwest Wednesday and a westerly flow with more sunshine will allow temperatures to reach the mid to upper 70's across much of the state. During Wednesday night and into Thursday morning a secondary cold front will move southeast across the state with little moisture predicted by both the 18Z NAM and GFS, as they keep most of the precipitation in New York.

 

Long Term: (Thursday through the Weekend)

 

High pressure will dominate with a northwesterly flow for Thursday and into Friday morning. Friday morning will be very cool and with the passage of the weak cold front, low-level moisture may be present and could help provide frost for the northern portion of the state. As the center of high pressure moves southwest and passes over the state on Friday clear and comfortable conditions will follow as the ridge sits over the region into Saturday. The 18Z GFS is showing a weak cold front from Canada dropping down behind the ridge on Sunday and providing the chance for scattered shower or storm. Otherwise, high pressure will begin to build back in from the north on Monday.

 

~ A.J. Herbert

Monday Evening Forecast

Synopsis:

Clearing skies will lead to a much more pleasant Tuesday. High pressure is forecasted to move into the region for the rest of the week and bring ample sunshine and decreasing cloudiness. This pattern will be with us for the rest of the week and weekend with very little chance of precipitation.

Discussion: An upper-level omega block will build over the central US tomorrow and persist through the beginning of the weekend. The only disturbances we will see during the forecast period will come from isolated shortwave pockets of energy ejecting from the Great Lakes.

Monday Morning Technical Discussion

Synopsis:

Skies will remain cloudy throughout most of the Commonwealth as a front approaches from the west.  Showers and thunderstorms may accompany this front, but it appears to be weakening as it moves eastward.  As a result, anything more than light rain will likely be confined to the southeastern quarter of the state.  After the front passes overnight, clearer, warmer, and drier conditions will move into the region.  These conditions will remain in the area throughout the week and into the weekend, bringing temperatures in the 70s, lows in the 50s, and much lower dew points. 

Short Term:

A front approaching from the west will cross the state in the afternoon and evening, pushing the present moist air mass out of the area.  Although storms were previously expected with this front, it appears to be weakening in Ohio, as not much rain or even high clouds are indicated on satellite and radar.  This, combined with the fact that both NAM MOS and GFS MOS are predicting cloudy conditions for all but the southeastern quarter of the Commonwealth, indicates that additional convection will be limited and  rain will either not materialize or will be light as the front moves through the state.  Showers and thunderstorms are possible near Harrisburg and Philadelphia, however.  After the passage of the front, models and MOS agree that high and low temperatures will be fairly steady in the 70s and 50s, respectively.

Long Term:

High pressure will build into the state following the passage of the front, leading to markedly lower temperatures and dew points.  Some clouds will linger on Tuesday, but starting Wednesday, clear skies are expected.  Temperatures will remain relatively steady in the 70s, with State College hanging around 75 and the Southeast approaching 80.

Patrick Higgins

Synopsis:

Unsettled weather will remain in the area on Monday after an eventful day of weather on Sunday.  Strong thunderstorms moved northeast across the state bringing lightning and heavy rain to many areas in the southern and eastern parts of Pennsylvania.  The cold front will linger on Monday sparking more thunderstorms in the same areas as Sunday's storms.  After the front passes there will be a welcomed change in the weather, with low humidity and seasonable temperatures for the rest of the week. 

Short Term:

Thunderstorms will continue to cross the state Sunday night associated with a moist, tropical air mass.  The unsettled weather will remain in the eastern part of the state on Monday before finally moving out in the evening.  Dew points on Monday will range from the mid 60s to 70 signifying the uncomfortable conditions that will be felt across the state.

Long Term:

High pressure will build Tuesday bringing a noticeable change in the weather for the rest of the week.  Cooler and drier air will set in throughout the Northeast with dew points in the lower 50s and temperatures in the mid 70s.  The conditions should be welcomed after a week of above average temperatures and humid conditions.  Abundant sunshine will be felt from Erie to Philadelphia as the high pressure builds over the Ohio Valley.           

Maximilian A. Vido