A Wet Week Ahead

Synopsis:

 

Unfortunately, unsettled weather we saw this week will continue through all of next week, bringing the chance for rain every couple days or so. With all the moisture in the air, temps will not change much. Expect highs around 70 and lows in the 50's, which is mild for this time of year. The only days that look to be rain-free are Monday and Thursday, so get outside while you can! Otherwise, be sure to have your umbrella handy - it's going to be a wet week.

 

Short-Term:

 

Expect batches of precipitation to begin affecting southern/central portions of PA very late tonight/early tomorrow morning. These will then dissipate and give way to the warm front from the stronger low pressure system to our souhwest. According to current GFS models, this system will then swing slowly up through the Ohio River Valley and weaken. After the warm front hits on Tuesday, the remnants of the cold front will rumble through on Wednesday and produce off and on rain throughout the day.

 

Long-Term:

 

After the fronts from the dying low pressure system have moved through, whatever remnants of that system will be sucked into the next, much stronger low pressure system up to our northwest in Canada. It looks to develop along a trough (associated with a low even farther to the north) and rapidly intensify over Wisconsin and Michigan. As it makes its way northwestward over the Great Lakes and into Canada, this storm's cold front has the potential to produce precipitation, and possibly some storms, from the Ohio River Valley up into Pennsylvania and New York and across northern New England.

 

This system currently looks to develop and strengthen significantly over a short period of time (1200Z on Thursday to 1200Z on Friday), and should be monitored closely for the potential for strong storms and heavier precipitation.

Sunday Afternoon: Break then More Rain

Synopsis:

The upper-level low over NY will quickly exit to the east-northeast tonight. A 1000-mb mid-latitude cyclone in the lower Mississippi River Valley, powered by a deep short-wave trough, will head toward our area... arriving Monday night and leaving Thursday. High pressure settles in for Thursday and a cold front looms Friday.

Models Used: 09Z SREF, 12Z NAM, GFS, HI-RES NAM, 18Z RAP (HRRR); Confidence: Average

Short-Term:

UL low exits. Result: dry; otherwise, no change until Monday night.

Tuesday through Thursday: Showers.

Long Range:

Thanks to high pressure, we'll get some sun toward the end of the week before the cold front moves through.

-Jaron Breen

Thursday Evening Technical Discussion

Synopsis

A strong disturbance has moved through the state bringing periods of rain to the commonwealth. This will also keep temperatures cool across the state through Friday. Behind this disturbance, more waves of low pressure will continue to move through before a cold front finally pushes through on Sunday.

Short term

The area of low pressure will continue to bring periods of rain to the state through Friday midday. After this, the skies will clear out Friday afternoon, and with this sun, there will be a pop-up convective showers. This will be story for Saturday as well as Sunday as temperatures rise into the mid 60's before a stationary front slowly slides south on Sunday. This will bring a few isolated showers on Sunday across southern portions of the state.

Long term

Later on Sunday, a low pressure system will move towards Pennsylvania. It will cause another round of rain beginning in the morning across western Pennsylvania. The rain will continue to move eastward during the day as rainfall amounts will range from 0.25-0.5". This rain will end by Monday and will be replaced by an area of high pressure. This high pressure will bring clear skies and temperatures will rise into the lower 70's each day through mid-week.  

Unsettled Weather Through Weekend

Synopsis:  A frontal boundary has pushed through the state and become stationary across northern Virginia, back through Kentucky and points westward. Waves of low pressure forming on the stationary front are moving northeast, bringing periods of rain to the commonwealth. It is also keeping temperatures cool across the state as it pulls in chilly Canadian air. The stationary front will persist through the weekend before finally moving south early in the week as a cold front approaches from the west.

Short term:  The stationary boundary south of Pennsylvania will continue to bring periods of rain to the state. The next area of rain is currently in western Pennsylvania and will be moving east overnight. The rain should be steady at times with up to 0.5" of precipitation possible state wide. Expect the rain to push out early Friday with partial clearing Friday afternoon. As the sun heats up the surface Friday, it is possible that a few convective showers will form, especially in the southern portions of the state. With the unsettled weather both days expect temperatures to remain in the mid 60's across the state. The front will start to slowly slide south on Saturday leading to only a few isolated showers on Saturday, again mainly in southern portions of the state.

Long term:  After a brief break from the widespread showers on Saturday, a low pressure system from Canada will begin making its way towards Pennsylvania. The low pressure will be weak, but will give the state yet another round of rain on Sunday. Expect rain to begin in the morning across western Pennsylvania and progress eastward as the day goes on with eastern regions seeing rain by late afternoon. Rainfall amounts should be light with 0.25-0.5" expected statewide. The rain will be out of the state by early Monday as high pressure pushes in behind the low pressure. High pressure will bring clear skies and warmer temperatures in the lower 70's to Pennsylvania for at least the first half of next week. 

Thursday Discussion

Synopsis:  A very slow moving cold front is draped along the northwestern part of the state slowly moving across the Commonwealth bringing showers to most of the region for the next day or so.  After its passage a deep upper level trough will descend from the north bringing more unsettled weather for the next few days in the form of showers and possible thunderstorms.

Short term:  As the cold front moves across the state showers will be popping up all over.  Come Thursday morning the cold front will only have made its way to about interstate 80 and become stationary.  This will set the stage for the ongoing short wave disturbances that will occur.  For the near term the ensemble forecasts are still unsure about total precipitation for the next two days.  However the eastern half of the state looks to be the best candidate for the greatest amount of precip to fall.

Long term:  Come the weekend we can expect the front to push off to the south and the upper level trough will give way to an even deeper upper level trough.  The newly formed deep layer trough will be in place Saturday and begin to ramp up.  A low pressure will form over the Chesapeake Bay due to PVA and the associated vort max from the deep upper level trough.  This will bring very unsettled weather for the eastern half of the state for Saturday and Sunday.  Some showers can be expected over the middle part of the state but the concentration of showers and possible storms will be to the east.  Come Monday the system will be moving along the northeastern coastal states and our region could see some lingering showers due to the cold conveyer belt.  Not much cold advection associated with the passage of this system, expect temps to remain around normal for both highs and lows. 

Wednesday Afternoon

Synopsis: Storminess ahead of a cold front will continue to bring clouds and showers to our region throughout this evening. The cold front will move through the commonwealth tonight bringing slightly cooler conditions. This boundary will stall just to our south and make way for several areas of low pressure. Continual showers will be the story for the remainder of the week and into the weekend. 

Short Term: Scattered showers will impact the commonwealth for the remainder of the night. Precipitation amounts will be between a tenth and a quarter of an inch. Thunderstorms should be limited for the entire state, although southeastern Pennsylvania may hear a rumble or two. Overnight, the boundary will move through the region. Relatively cooler conditions will follow in it's wake. 

Long Term: The boundary will stall just south of Pennsylvania. This will allow several disturbances to make their way into our area. Clouds and showers will be extremely prevalent for the rest of the week and the weekend. This boundary will also allow for warmer conditions south and east while locations in the west will be cooler, especially overnight.

Cooler today, then seasonably pleasant the rest of this week

Synopsis:

 

After the FROPA on Saturday, the 540-mb. height lines dove down towards PA yesterday and today. This translates into cooler weather for one more day, before we see a ridge of high pressure moving towards PA and bringing more seasonably pleasant temperatures with it. However, by Wednesday, we will see a cold front advancing towards the state, merging with a frontal boundary coming up from the Ohio River Valley. This will bring showers across PA, and possibly a few isolated thunderstorms as well. By Wednesday night, the cold front clears out, but the stalled frontal boundary stays behind. It will slide to the north again (the stalled frontal boundary, that is) by Friday and into the weekend, bringing scattered showers. Temperatures after today will stay seasonably pleasant, even after Wednesday's cold front passes through.

 

Short-term:

 

Still running cool today due to lowered 540-mb. height lines across PA. Leftover moisture in the upper levels will continue to give clouds to the western and central portions of PA (think widespread pancake cumulus), and temperatures will run a good 5-10 degrees below where they should be this time of year. However, by tomorrow, a decent-sized area of high pressure will move from the south and west over PA, which will provide a beautiful day for tomorrow. It will be short-lived, though, as clouds are once again on the increase for Wednesday's two systems that will clash just to the south of PA ...

 

Long-term:

 

A cold front is currently making its' way through central Canada, and will move south and east over the Great Lakes towards PA. It should pick up a decent amount of moisture moving over the Great Lakes - hence, a good chance of showers (and possibly a few isolated thunderstorms as well). Another system (a frontal boundary) is moving from the South towards the NE, and the two frontal systems are expected to merge by some point Wednesday. Once the cold front pushes through, this frontal boundary will move south for Thursday. However, by Friday, it looks to slide north again, and it will be a question of how much moisture is associated with it for Friday and into the weekend, and what areas of PA see showers. With the cold front passage on Wednesday, there really isn't any very cool air behind it, so temperatures will only fall a few degrees Thursday and into the weekend. Not too bad of a way to start the first full week of fall!

Fall at Last

Synopsis:

The cold front that affected our region yesterday has rolled out of the area, leaving very cold temperatures in its wake. Freezing, in fact! Watch for frost and freeze advisories during the night hours for the next couple nights with temperatures dropping into the mid-30's. It will be warmer during the afternoons, though, with expected highs in mid-upper 70's. Aside from the chance of a storm Wednesday afternoon, this seasonable, cool weather will be the trend for this week.

Short Term:

As stated the cold front that passed through yesterday has ushered in our first bit of fall weather, with high pressure and chilly Arctic air.  Temps will fall near the freezing mark through Illinois, Indiana, Ohio, and into western PA.  Watch for frost and freeze advisories overnight in these areas and up to the north.  Freeze threats will gradually diminish as temps overnight slowly increase of the next couple of days.

Long Term:

A batch of unsettled weather looks to affect our region on Wednesday.  Currently, models are not predicting anything more than rain showers, but this could change over the next few days.  Conditions across the state should be monitored closely for any conditions that would further storm development on Wednesday.

After this unsettled weather passes by, expect amazing fall weather into the weekend!

Sunday PM: Settling Down then Mid-Week Showers

Synopsis:

The upper-level low that powered the cold front is still with us; clouds and drizzle will linger overnight. High pressure will approach from the southwest, clearing things out until mid-week. A cold front will then approach the Commonwealth Tuesday evening and then pull away Thursday night. High pressure is expected to build back in for the end of the week.

Models Used: 12Z NAM, 15Z SREFS, & 12Z GFS; Confidence: Moderately High

Short-term:

Future shifts will need to forecast cloud cover over the next day or so. The SREFs showed that measurable precipitation was possible in western and central PA over the next few days and also showed that the timing of the front's arrival was in question at dinner-time Tuesday in western PA. Temperatures rising slowly until the front passes.

Long-rage:

The cold front will move through, again timing will be an issue. Temperatures do fall after the front, how much remains to be forecasted.

-Jaron Breen

Fall Arrives

Synopsis:

We will see a beginning to fall weather here in PA after a cold front swings through tomorrow. Expect rain and windy conditions along associated with this front throughout the day tomorrow, along with the chance for a few scattered showers tonight developing ahead of the front. So, it's going to be a rainy Saturday, but all that precipitation will clear out and leave us with a beautiful, partly cloudy, and much cooler start to next week. With highs barely reaching into the 60's and lows dropping into the 30's overnight, it's definitely the start of fall!

Short Term:

Unfortunately, the front looks to sweep through central PA right around game time, at 2000Z. This timing is generally agreed upon my most models. A level of uncertainty remains, though, pertaining to the amount of expected precipitation. The more resolution the models have, the less rain they show falling here in Centre County, with most of the precipitation falling in southeastern and northwestern PA. This may be a good sign… but still expect some rain just in time for the game tomorrow.

Long Term:

After the front sweeps through, cooler temperatures will blast their way into our region. Expect lows overnight dropping into the 30's, possibly below freezing in higher elevations! This fall weather will arrive just in time for the actual season, and will dominate our weather through the middle of the week. At this point, high pressure looks to build in over our region, keeping us cool and dry through the end of next week and into the weekend.

Thursday Evening Technical Discussion

Synopsis

The next couple of days will feel like autumn as an upper level trough remains overhead. It will bring cool and crisp conditions just in time for the start of the fall season.  A wet weekend is in store for much of the commonwealth.  The northwestern areas will receive the highest amount of precipitation with the southeast seeing much less in the way of rain. After this system, a ridge of high pressure will build in but the temperatures will remain cool.  \=

Short Term (Now thru Sunday)

After a beautiful day, temperatures won't cool of much tonight due to the warm advection. On Friday, the clouds will move into the state early Friday morning. A front will move itself over PA which will help produce scattered showers throughout central PA. Another plume of moisture will move east out of the Ohio Valley. This ejected moisture will ride up the northwest corner of PA, dumping rain on Pittsburgh and Erie. This heavy rain will contain sporadic downpours through Saturday afternoon.  Areas in Bradford, Johnstown, and Clearfield may see light showers. Locations along the eastern half of the state will see showers late Saturday afternoon into the evening.

Long Term (Sunday evening through Tuesday)

The rain will end Sunday morning. Behind the front, strong cold advection will remain throughout Sunday. This will cause leaving high temps state wide to struggle to climb near average for this time of year.  An area of high pressure will move into the area, but the 500mb trough will settle in place. This will keep the flow out of Canada and cause us to remain in a cold air mass throughout mid-week.