Wednesday Afternoon

Synopsis: The remnants of hurricane Sandy will continue to dominate the weather across the commonwealth for the next week. Cloudy and below normal temperatures will be persistent into the weekend. The large upper level low pressure associated with Sandy will eventually slide well to our north and allow a northerly flow to develop. This will most likely lead to an active weather pattern for later next week.

Short Term: Scattered showers, snow showers, and drizzle will linger tonight and tomorrow as an overall easterly flow persists across Pennsylvania. Some showers in the western half of Pennsylvania are lake enhanced and heavier precipitation rates can be found in these areas. Snowfall will generally be confined to the ridges and northwestern most portions of the state. Surface temps are generally marginal which will limit widespread accumulation. Low level clouds and rain showers will continue into early Friday. 

Long Term: This weekend, the remnants of Sandy will gradually scoot to our north and a northwesterly flow will develop across the state. Cold air advection will pick up allowing temperatures to stay well below normal. Expect highs to struggle to get past 50 on Saturday and Sunday, while overnight lows will dip well into the 30s. Accompanied by this northwesterly flow will be leeward clouds. A mix of clouds and sun can be expected for the weekend.

Sandy

Synopsis:

Severe weather is on the way for the commonwealth as Hurricane Sandy moves in on Monday. Even though it won't make landfall until nighttime, expect heavy rain and strong, gusty winds during the day. These conditions will be associated with Sandy, which has developed into an unusually large storm with both tropical and extratropical characteristics. Basically, it's a giant Nor'easter with an attitude, and its sights are set on Pennsylvania. After making landfall in New Jersey Monday night, Sandy is forecasted to move into central PA before making its slow turn towards New England. The worst conditions across most of the state will be Monday night through Tuesday as the storm moves through the commonwealth. Expect 20-50 mph winds with gusts to 75 mph and heavy rain, amounting to 4-8" before Sandy moves out of the region on Friday. If you are not prepared for these conditions, you only have one day left. Stay safe everybody.

Mon-Wed:

GFS and the Euro models have converged on a Cat 1 landfall over the NJ/Delaware coastline tomorrow afternoon.  Worst case scenario will be a landfall over central NJ, as this would push all the water up into NYC, as well as westward through the Long Island Sound and, again, into NYC.  This is definitely still a possibility, although a central NJ landfall is trending towards the northern area of the cone of uncertainty.  Either way, Sandy's wind field is simply diabolic.  40 mph winds extend 500 miles from the center and 75 mph winds extend 175 miles!  So, whether Sandy ultimately makes landfall in Delaware or New Jersey, all the major cities along the East Coast will still be impacted with at least tropical storm force winds, heavy rain, and historic storm surge.  These same cities could also see record low pressures.  The record lows in many of these cities are in the 960-965 mb range.  Sandy is currently forecasted to come ashore as a sub 950 mb system, which would easily smash these records.

Thurs-Fri:

Rain lingers over the commonwealth as the winds die down and Sandy's remnants scoot out of our region and into the Northeast, leaving most of the commonwealth with 4-8" of rain.

Sun. PM: Sandy is 24-36 hours from NJ-NY landfall

Hurricane Sandy Info (NHC):

Adv. Time: 5 PM Sun. 10-28-12
1) Location: 470 mi. SSE of State College
2) Movement: NE at 10-15 kt. and steady
2) Pressure: 952 mb and steady
3) Wind: 75 mph (65 kt, 33.4 m/s) and holding

Front Info: Stationary over the I-476 corridor

UL Trough Info: Negative Tilt from Springfield, IL to Birmingham, AL

Merger Status: Slow

FORECAST:

Sandy is forecasted to fully merge with the mid-Latitude system in the next 12-36 hours according to NHC, which we agree with. The official landfall location is Atlantic City, but that appears to be too far to the south given the guidance (GFS, CMC, NOGAPS, & ECMWF - 12Z Runs). We cannot rule out a landfall between Atlantic City, NJ and Suffolk Co., Western Long Island, NY... for now, our call is Toms River in north-central NJ at midnight Monday into Tuesday. The storm will roughly follow I-195 in NJ, I-380 in PA, & I-81 in NY. Based on the guidance, the bulk of the rain will be to the left of the track (a cold-core characteristic) and the bulk of the wind will be to the right of the track. As for the snow, look for a coating to two inches in Cambria County (LH Zone) from Monday night until Thursday AM. On Wed. AM, the NC, SC, RV & NSQ regions will begin seeing a mix of rain and snow with no accumulations likely. Most of the effects will start to dwindle on Thursday with some lingering showers and breezy conditions possible on Friday.

-Jaron Breen

A Wet, Wild Week Ahead

Synopsis:

Low clouds and fog blanketed the eastern half of the state most of today but most of the western half saw plentiful sunshine. Later tonight a cold front will begin to cross the region from west to east causing a drop in temperatures across most of the state. Tomorrow will be a mostly overcast day across a good portion of the state with rain most of the day in the western areas associated with the front that will pass through tonight. The eastern half will be generally dry with some patchy drizzle but nothing more significant that that. Penn State's game with Ohio State should be cloudy and cool but rain should stay away until the overnight hours. Sunday is when the next major weather maker moves in as what is now Hurricane Sandy will make its way to the Northeast and cause heavy rain, strong winds, and flooding for a good portion of the state with possible heavy accumulating snow across the higher levels of the Southern Appalachians.

Weekend Outlook:

After the clouds build in today and tomorrow morning, the cold front looks to impact the western portions of the commonwealth around 18Z-21Z, according to the NAM.  This front will then stall around 3Z Sunday morning in the wake of Sandy, forecasted to be sub-960 mb at that point.  While Sandy's precipitation won't be affecting the commonwealth much until Monday, expect winds to start picking up from the north at around 15-20 mph across most of PA.  These strong, northerly winds will be a key factor in determining precipitation types (rain/snow/mix) over portions of PA in the nights to come, especially in Pittsburgh and the Laurel Highlands areas.

Long Term Discussion:

Whether Sandy makes landfall in southern NJ or Long Island, we will still feel similar effects here in PA.  Currently, GFS has Sandy hooking into CT/RH/Long Island around18Z on Tuesday afternoon, while the Euro shows Sandy tracking through central NJ and southwestward into the DC area around 12Z on Tuesday morning.  Both of these models show Sandy making landfall as a slow-moving, sub-960 mb system with a very large windfield.  This is why the exact landfall location doesn't matter for us here in PA.  Conditions will worsen rapdily closer to the coast.  As a result, Philadelphia will bear the worst of the storm Monday through Wednesday, central locations will see tropical storm conditions (heavy rain and strong winds around 40-50 mph), and western locations will just experience another wet, windy day with a chance for snow in elevated locations.  Expect widespread wind and water damage and power outages from this storm from the mid-Atlantic up through New England.

Stay tuned to your local weather station for updates on this potentially devastating storm.

Thursday Afternoon Technical Discussion

Synopsis: The state of Pennsylvania has seen two different stories as far as the weather goes today. Eastern Pennsylvania saw an easterly flow at lower levels near the surface last night which brought their dewpoints up and created a thick layer of fog up to about 950mb. This fog had a difficult time burning of during the day as a continued easterly flow brought more moist air. For this reason, many places across eastern Pennsylvania stayed foggy all day leading to temperatures only in the upper 50's to lower 60's in some places. The western half of Pennsylvania was able to stay mainly clear today with a southerly wind and so they got their temperatures well into the upper 70's and some in the lower 80's. As we move towards the weekend the easterly flow will continue to lead to showers and cloudiness across eastern Pennsylvania while a cold front approaches from the west. As the cold front does so, Hurricane Sandy will phase with the cold front and make landfall somewhere in the Mid-Atlantic or Northeast early next week.

Short Term: (Friday – Saturday) As we look at the forecast it will be broken down into two parts. The first is eastern Pennsylvania which will again see moist easterly flow off the Atlantic Friday. This will cause yet another round of fog and keep temperatures down some. As the day goes on and the high pressure moves off the coast, the winds at the surface will start turning more southerly which will help to eat away the fog as warmer air is advected. Winds aloft will turn more easterly however, so we will see the fog burn off some but mid-level clouds will take its place. The moist air aloft may even help to create a few showers across eastern Pennsylvania Friday. As Saturday approached across eastern Pennsylvania, clouds from Hurricane Sandy will begin wrapping in as Sandy is a large Hurricane around 2000 miles wide. There may be a few showers from these wrap around clouds Saturday but it will be cloudy for the most part. Western Pennsylvania will see some more sunny skies on Friday and temperatures again in the mid 70's. Some clouds may move in during the afternoon from the approaching cold front which will stop western Pennsylvania from getting as warm as they were on Thursday. As Saturday approaches, western portions of the state will see clouds on the increase with some showers possible early as the cold front pushes through the state. The showers should last for most of the day, and cooler weather will accompany them leading to temperatures in the mid 50's. Portions of central Pennsylvania will see a mix of the two extremes with some fog possible early Friday which will burn off allowing for temperatures in the 60. Clouds will increase during the day on Saturday as the cold front approaches. Showers will begin in central Pennsylvania in the late afternoon and continue overnight.

Long term: (Sunday – Monday) At this point the forecast gets somewhat difficult as there is great spread in the models still. The European model has Sandy phasing with the cold front on Sunday and bringing rain and wind to Pennsylvania as early as Sunday. If this were to happen, eastern portions of Pennsylvania should expect periods of rain Sunday which will become heavier on Monday. Winds will also pick up in these areas as we head towards Monday with some areas likely seeing gusts between 50-70 mph. Heavy rain is also likely with areas possible seeing 1-3in of rain by Monday. Western portions of the commonwealth would see scattered showers with more steady periods of rain moving in Monday. As Sandy makes landfall in this case, the storm would wrap around colder air to western Pennsylvania and so some mountains have a chance of mixing with some snow by Monday. If the GFS were correct, the cold front would stall over Pennsylvania and Sandy would not phase with the cold front until late Monday into Tuesday. This would lead to scattered showers across the state Sunday and Monday. Since the NWS required balloons launched every across the United States every 6 hours starting 18z Thursday, the model runs from here on will likely have a better handle on what will actually occur. 

Zachary Fasnacht

Synopsis: High pressure will dominate the weather across most of PA for the next 36 hours before some changes occur. By Friday afternoon a cold front will approach the NW and continue to move across the region Saturday. This will bring cooler temperatures into the region along with showers on Saturday. However, the bigger weather story could be from Hurricane Sandy, which could bring the potential for rain, snow, and gusty winds into our region by Sunday Night and Extend into next week.  

Short Term: (Thursday – Saturday) For Thursday and into much of the day Friday our weather will be dominated by high pressure. This will lead to temperatures in the 60's and 70's across much of the state under sunny skies. But by Friday afternoon clouds will slowly build from the west as the cold front approaches. This will set the stage for cooler conditions and rain showers for Saturday.  The NAM shows less than a ¼ inch of rain for regions east of State College, but the western third of the state could have heavier rains.

Long term: (Sunday – and behind) Saturday afternoon the front will slow and stall as Sandy begins to slowly make its way northward.  By Sunday the trough begins to become negatively tilted and deepen. The uncertainty exists whether Sandy phases with the trough and at what point this happens. The exact track could have big implications for what pans out. The 12Z European model paints the storm going right up the Delaware River with copious amount of rain and wind by 12Z Monday. This would also lead to heavy amounts of snow across the western mountains of PA.  On the other hand the 18z GFS takes Sandy out to Sea and develops another low along the coast of New England, this then retrogrades southward. This would produce some snows across the northern and western part of the state for Tuesday. There is still great uncertainty in the forecast being 4-5 days out, but the potential exist for a high impact weather event across the entire state of PA. So state tuned to the Campus weather service the next several days for updates.

A Nice Week (For Some)

Synopsis:

I am the bearer of good news! The nice weather we've been seeing for the past couple of days will continue due to the perseverance of the strong high pressure system sitting over the commonwealth. But, I lied... this may only be true for the southern portions of PA. Areas to the north may see some off and on showers through Tuesday and into Wednesday morning, while areas to the south are expected to remain dry. Other than that small disturbance, though, expect warm temperatures and partly clear skies. Enjoy the nice weather while you can, because a cold front and a possible tropical cyclone loom next weekend. Stay tuned for updates on these potentially strong weather systems.

Short Term:

The dominating high pressure system will continue to influence our weather for the next couple of days.  Although, a batch of moisture looks to sneak between the high over souther PA and another high up in Canada around 1200Z on Tuesday morning.  GFS shows the southern high doing it's job and keeping the precipitation from reaching into southern PA.  On the other hand, NAM shows the chance for isolated showers extending down through the commonwealth, especially Tuesday night.  A chance of a shower lingers in the east on Wednesday morning, and then the system moves out.

Long Term:

After the small disturbance passes through, a nice, strong ridge of high pressure looks to build to our east off the coast of New England.  This will bring a warm, southerly flow and push temperatures well into the 70's (10-15 degrees above average for this time of year).  This trend will continue through Friday, until the next big system hits.

Really Long Term:

GFS has showed a well-developed cold front moving through the commonwealth on Saturday evening for the past couple of days.  This is still far out, but GFS has been consistent with the "intensity" and timing of this front.

Also, a tropical system looms in the Caribbean, and looks to head northward over the next couple of days.  There is MUCH uncertainty about this system after it slides to the east of Florida.  Will it head east into the Atlantic, as GFS forecasts?  Or will it rapidly intensify, slide right up the coast, and make landfall near the Chesapeake Bay, as EMCWF predicts?  This is definitely something to keep track of.  If it heads up the coast, it will definitely influence our weather in PA right around the same time as the cold front moves through.

Sun PM: Warm-up and Something on the Horizon

Synopsis:

Our cold front powered by the cut-off low is heading NE into Canada and a 500-mb ridge will build in, allowing temperatures to climb. Surface-based high pressure will settle south of here, providing us with clear skies. A low pressure system in TX & OK will bring rain to the Commonwealth Tuesday night into Wednesday, but the high is directing it north of us. Those north of the turnpike, especially north of I-80, will see the best chance of rain. The high then moves to the north and east as we wait for a cold front that will head on through next weekend.

Models Used: 12Z NAM, GFS, & ECMWF; 15Z SREFs

Short-term (Through Tuesday):

The high pressure will be in control for the first few days. The SREFS place it over the Central Appalachians in the 1020-1030-mb range.

Long-Range (Tues. PM - Fri AM):

The low looks to go along US-6 - very weak though. Enough to generate a shower throughout the Commonwealth, mostly in the northern 2-3rds of the state.

SREF POPs: 45-60%  along & north of US-6; 25-50% between I-80 & US-6; 10-25% along & south of the Turnpike.

Extended Range:

Cold front: looks to slow down as it readies to sweep through because of the presence of a probable tropical storm Sandy (70% chance of development over the Carrbbean according to NHC) moving close to the US. Something to watch closely!

-Jaron Breen

Technical Forecast

Synopsis:

Well, conditions have gotten a bit better since yesterday, but not by much. Expect some lingering showers across the commonwealth today and into Saturday, especially in eastern PA. Once this systems finally rolls out, though, high pressure will settle in over our region, bringing sunny skies and warmer temperatures, even pushing 70 by mid-week! This system will dominate our weather through most of the work week, until a potentially strong low sweeps through from the west on Friday. Overall, though, enjoy this week, because the weather is going to be great!

Weekend Forecast:

Expect isolated to scattered showers to continue impacting the region through early Saturday afternoon (around 1800Z).  After this, a strong high pressure system will build in from the southwest and park itself over the Northeast, providing us with a great few days.

Long-Term Outlook:

This strong high pressure system will dominate our weather through most of next week.  The only exception might be Tuesday night as an area of unsettled weather sneaks between the high pressure to our south and a high up in Canada.  Other than that, expect sunny skies and warming temperatures through the middle of next week (at least!).

Thursday Evening Technical Discussion

Synopsis

The main feature that will control this weekend's weather is the slow moving upper-level low. This low will bring the potential for scattered showers on Saturday and Sunday. Behind this low, high pressure will move in and bring nicer weather to the region as we enter next week.

Short Term (This Afternoon through Sunday)

A strong area of convection is currently moving across Central PA. During the next couple of hours, it will progress to the east bring heavy rain with it behind it dissipates overnight.  Behind this upper low, cold advection will commence along with enhanced clouds and moisture. Lingering clouds over the commonwealth will remain in place as the trough moves into the area. Both the 12z NAM and GFS keep the upper level trough in place through Sunday. A surface ridge will eventually build in and start to push drier air into the area. Things will begin to look up on Sunday as the clouds break due to higher pressure nudging into the area.

Long Term (Sunday night through Wednesday)

Behind this trough, a surface ridge will push into Western PA Sunday evening. It will position itself over the Ohio River valley which will create a northwesterly flow over the area. This high pressure will remain through the middle of week allowing temperatures to moderate under mostly sunny skies.   

tech disco 10-18-2012

Synopsis

The premise for this week's weather in PA will be the progression of a slowly moving upper level low that will churn up some storms along a front that will be moving throughout tonight and daytime tomorrow.  This system will have the potential to produce thunderstorms within the ridges and valleys, but over the course of the next 24 hours, this front will govern the state's weather, and then the vortmax will takeover until high pressure nestled inside a ridge aloft will round out the weekend.

Short Term (This Afternoon through Saturday)

A front currently draped across Ohio, Michigan, and Kentucky will progress into the state later today, but the showers ahead of the front will startup in Pittsburgh around 3pm (19z) this afternoon. These showers will trudge across the state, turning into storms producing heavy rainfall by 8pm (0z). As long as the strip of positive vorticity that is feeding this front holds true, Central PA will see heavy rain throughout the early parts of tonight, eventually dissipating as the vort max shifts north within the next 3 hours. Both the 12z NAM and GFS agree on this, and topography will definitely force the lift necessary for these storms to intensify. As this progress and reaches the lee side of the most eastern ridge, the system flattens out into more moderate persistent rain throughout the eastern half of PA, leaving its final drops up by Scranton around 21z Friday.  Behind this lies and area of modest cold advection, but the upper level flow will remain zonal, and the clouds and present moisture will prevent any drastic drops in temperature overnight Friday . Lingering clouds in the west will remain in place as the trough begins to take control of weather in the west, with clouds being churned up and showers being resolved by both the 12z NAM and GFS, but within the south and east portions of the state, a surface ridge will start to help dry the lower troposphere and keep the vortmax energy from affecting the east.  The vortmax will sweep across the stzte Saturday afternoon, but only clouds will make it though with a limited potential for a spotty shower east of the Appalachians.

Long Term (Sunday and beyond)

Once this trough passes through, the surface ridge will start to squeeze through the mountains. Its center will nestle itself over southern WV, western VA, and eastern KY and TN, and by Monday, a ridge aloft will move into the state, holding strong for Monday, at least until Wednesday. The upper level low will stick around for Sunday, but leaving little influence on the state as clouds remain scattered throughout the underlying areas, and by Monday it will be completely out of our area. 

Synopsis: High pressure that has dominated the region for the last few days will continue to move off the coast.  A strong Upper level low with an associated cold front will move into the region for Thursday and Friday.  Temperatures this weekend will be cool in the wake of this front averaging several degrees below normal. Upper level low will spread scattered instability showers and clouds over the region Saturday. Late weekend and early next week expect a strong high pressure to move in brining mild late October temperatures.

Short term: Thursday –Saturday

Thursday expect a deteriorating weather day across the commonwealth as showers and possible thunderstorms move in from the west in the afternoon hours. Isolated severe storms cannot be ruled out given the dynamics and SPC slight risk area over the majority of PA.  The NAM and GFS both have the region getting a healthy dose of rain between .25-1 inches, but amounts could be higher in thunderstorms.  Friday afternoon the clouds will break some as the trough digs into are region. Saturday the GFS has the upper level low spinning over us, which would bring the coolest conditions of the weekend along with possibility of showers. Expect a strong high pressure to move in for the ladder half of the weekend.

Long term: Sunday – Monday

High pressure will set up off to our south pumping in warm dry air. Temperatures will be well above normal as we head in mid and early next week.  Expect fair weather skies for Sunday and Monday with little in the way of cloud cover.