Synopsis

Sunny skies are in the short term and long term forecast. Temperatures will be right around average for the forecast period. No precipitation is expected.

Short Term (Friday Night – Sunday Night)

A strong high pressure system is what is allowing for our sunny skies and comfortable temperatures. Highs will be around 50 degrees over the weekend and lows will be around 30.

Long Term (Monday Morning – Tuesday Night)

Sunny skies and comfortable temperatures will continue. High temperatures on Monday will be a little bit cooler than over the weekend. High in the mid-40s are to be expected. Cloud cover will increase Monday night and into Tuesday. Conditions will be mostly cloudy through Tuesday night. Lows Monday night and Tuesday night will be in the mid-30s and highs on Tuesday will be in the low 50s. 

texh disco 11-15-2012

Synopsis

The upcoming weather for the weekend will be rather dry, but also sunny as a blocking high will dominate our weather pattern for the weekend.  a prospective nor'easter that has been in the news will not be influential much along the northeastern coast, but it is something to keep an eye on for the week.

Short Term (Now throughout Friday night)

Currently, the state is along a surface high pressure ridge that is extending all the way into Missouri. This ridge will dissipate a little it gets sandwiched by a cold front up in northern Ontario.  A shortwave trough will make its way into the state on Friday afternoon (around 18 to 21z) however this will leave little influence on our weather directly, and as day turns to night, this shortwave will undergo a sharp turnibf as a 500mb ridge, oriented NE to Sw, will deform this shortwave and will begin to cut it off from the mean flow.

Long Term (Saturday through Monday)

Saturday morning, the shortwave will turn a strip of positive vorticity toward the southern parts of the state(in a windshield wiper-like fashion). With this, positive vorticity will get sucked into the cutoff low hat will be hanging out to our south over Eastern TN, northern GA, and western Carolinas. This low will enhance a coastal system that will precipitate over the Carolinas and eastern Georgia.  this is in part due to the wide 500mb trough moving toward us in addition to the surface high shifting to the Northeastern U.S. on Sunday, he high to our northeast will begin creating a cold air damming scenario that will keep temperatures below average locally and across the East coast. This will remain in effect for Monday as well, and the high to our northeast will serve as a blocking high that will push he southern cutoff system out to sea and not the recovering east coast.

Wednesday Afternoon

Synopsis: A boring weather pattern dominated by high pressure will set into place over the next week. The next area of active weather will be a low pressure system off the East coast.

Short Term: An area of high pressure will exist to our north. This will create calm and sunny conditions across the commonwealth through the weekend. A small shortwave may pass by the region on Saturday, bringing a chance of clouds. 

Long Term: Generally, high pressure will dominate the long term forecast. The weather pattern will be fairly inactive.

Sun. PM: Big Changes!!!

Synopsis:

A cold front is coming, but first, that warm front has brought quite a warm spell to the Commonwealth, huh? Temperatures in the 50s and 60s won't last as a powerful "arctic" cold front is blasting through the central plains and southeastern U.S. at this time. It'll get to the state tomorrow night and be out of here Tuesday morning. A strong high pressure system will then move in from the west, bringing us the cold air.

Models used: 12Z NAM & GFS

Short-Term:

Highs are in the 60s throughout PA and will be for the day tomorrow. The front will bring showers, maybe some thunder, to the state as it passes. Given the warm air in place and severe weather climatology, thunder cannot be ruled out in the western and southern portions of PA. Once the front passes, temperatures could drop by as much as a degree Fahrenheit per HOUR!!! Some places in Oklahoma have achieved rates that high. This is typical "behavior" of an arctic cold front.

Long-Range:

The projected intensity of the high may reach the 1040-mb mark, a typical aspect of a Continental Arctic air mass. Also, the Arctic Oscillation is projected to go negative, allowing for cold air to invade the U.S.

5-15 Days Out: Trends are hinting at a nor'easter set-up around the Thanksgiving holiday. There appears to be no warm air invasions before this storm and the NAO is going negative over the course of next weekend, a favorable indication of an east coast storm track and snow as the primary precipitation type. However, just like Sandy about three weeks ago, it's far away but worth watching.

-Jaron Breen

5-Day Outlook

Synopsis:

Today begins a stretch of relatively calm weather conditions that will last into Monday. The Commonwealth will be under a ridge of high pressure through the weekend until the next disturbance comes late Monday into Tuesday. For the meantime, expect temperatures to moderate from the biting 20s and 30s that was present this week to 60s this weekend and Monday. Some areas could possibly reach the low 70s, especially on Sunday. Despite some clouds tomorrow, a beautiful day is on tap for the Commonwealth Sunday. Monday begins the transition day as clouds will increase in the anticipation of a cold front that will pass through the state Monday night and throughout the day Tuesday. So, enjoy the warm temperatures and calm conditions this weekend.

Weekend Outlook:

A small disturbance looks to move through the region late tonight into early tomorrow morning. Earlier models indicated a good chance of precipitation from this system from Erie down through Centre County, but it appears to have weakened. Expect scattered sprinkles from this disturbance, not anything more. After this passes, expect unseasonably warm weather throughout the state! The clouds will dissipate Saturday night, leaving us with a gorgeous Sunday filled with sunshine and highs in the 60's across the board.

Early Next Week:

Our western low (a.k.a. Winter Storm Brutus) continues to strengthen and looks to have decent impacts on the Northern Plains (primarily in the form of steady snowfall and strong winds). The system looks to turn northward and head into Canada once it reaches the Lakes, but that won't spare us from its cold front. Current GFS models predict the front to move into western PA late Monday night (around 00Z) and blast straight through the region, leaving death and destruction in its wake. Actually, it won't be leaving behind any of that (hopefully), but it will leave us with wet conditions and very cold temperatures.

Thursday Aftn Technical Discussion

Synopsis: The coastal storm that gave many areas of New Jersey, New York and points north inches of snow has moved well north of the region and is now affecting northern New England. High pressure moving in behind the storm will lead to a pleasant weekend.

 

Short Term(Friday and Saturday): High pressure is moving in from the Ohio Valley and should bring a northwesterly flow to the state as well as clear skies. As the high pressure moves east on Saturday, a warm front with the storm in the Midwest will push into the northern portions of the state leading to a few light showers in northern Pennsylvania and some cloud across the state. At this point the high pressure will be east of most areas allowing for more of a southwesterly flow and much warmer temperatures.

 

Long Term(Sunday-Monday): With the high pressure pushing of the east coast, a southerly flow should continue for all areas bringing much warmer air. Many areas will be well into the 60's on Sunday with southern portions of the state near 70 degrees. Expect the pleasant weather to continue Monday as the high pressure slowly slides further off the coast. Temperatures will again be well into the 60's Monday with some areas into the 70's. As Monday continues clouds will move in ahead of the cold front that is expected to push through on Tuesday. 

Wed Night

Synopsis: Coastal low pressure system will continue to slide up the mid atlantic coast, bring snow to portions of eastern PA into tomorrow. As this system departs, upper level ridge will move in and dictate our weather through early next week.

 

Short Term: Light to moderate snow will continue to fall in southeastern PA, as a upper level trough phases with the southern branch of the jet and allows for the deepening of a coastal low. This nor'easter will bring minor snow accumulations to the Philly metro, but accumulating snow will not slide any farther west. Conditions will clear out during the day Thursday. Broad northwest flow will keep temperatures well below normal, especially as we get into tomorrow evening.

 

Long term: Upper level ridge will move in by Friday and deepen with time. Southwest flow will allow a general warming trend into the weekend and beyond, especially late in the period. Tranquil weather will be the story, as surface high pressure takes hold. Strond cold front will pass through the region early next week, bringing temperatures back down in the long term.

Sun. PM: Nor'easter Coming

General Discussion:

Cloudy skies will begin to clear tonight as high pressure approaches from the northwest. An area of low pressure in the southeastern states will slide up the coast during the work week. Election Day should be dry, but clouds will build overnight as we await the precipitation. Most of the precipitation, snow, will be confined to the eastern half of the state Wednesday afternoon through Thursday evening: rain and mixed precipitation is anticipated east of I-476; the heaviest snow is likely in the Susquehanna River Valley; and light snow in the mountains of central PA is probable. There is another scenario where this storm goes out to sea, which after Sandy's destruction would be ideal. However, based on the models' performance with Sandy, the latter, "out-to-sea" scenario is least likely to occur. After the snow clears, clouds will linger for the remainder of the work week. Temperatures, throughout this week, will stay below average.

Models:

12Z GFS: Out to sea; 12Z European had the storm closer to the coast. I think we all know which model performed the best with Sandy.

Note (High Pres):

If that high takes a more northerly route and all else stays the same, you can scratch the rain & mixed precip. for the Delaware River Valley.

Note (Amounts/ Ratio):

I think a 10:1 ratio works well. 2-4" Central PA; 4-8" Along & W. of Susquehanna River (SR); 3-6" East of SR to I-476; 2-4" along I-476; coating to 2" before the changeover in eastern PA.

-Jaron Breen

Synopsis

The remnants of Sandy are well off the northeast now, but some scattered showers, and even some winter precipitation are still sticking around. All precipitation should be over by Saturday night and skies will clear. 

Short Term (Friday Night - Sunday Night)

As the remnants of Sandy move farther and father to the northeast, the chance of precipitation will diminish. All precipitation should be out of the area by tonight for western parts of Pennsylvania, and for eastern parts of the state, by Saturday night. The pressure gradient is still pretty strong, so gusty winds will continue though Saturday. Gusts in the 20-25 mph range can be expected, but by Saturday night winds will calm to under 10 mph. Saturday and Sunday should be mostly cloudy for much of the state. Highs will be in the mid 40s for much of the state and lows around the 30 degree range. Skies will start to clear Sunday night. 

Long Term (Monday Morning - Tuesday Night)

High pressure will be building back in across the region, and sunshine will finally return. Highs can be expected to be in the 40s and lows in the upper 20s to low 30s. A low pressure system will be developing out over the Atlantic in the southeastern United State. This system will make its way up the coast and develop into a Nor'easter and has the potential to impact the Northeast United States unless it goes out over the Atlantic. It's too early to say whether it'll impact land or go out over the sea, but with many still picking and cleaning up after Sandy's destruction, let's hope it goes out over the sea. If it were to make landfall, it looks like it'll occur on Thursday as of right now. Whether it hits land or stays out over the ocean, it is definitely something to watch for. 

 

tech disco 11-1-2012

Synopsis

With Sandy finally dissipating and merged within a weakening trough, her remnants will remain in the form of scattered showers throughout the Northeast. Our concern for the upcoming weekend will be  the possibility for lake effect precip throughout the northeast area of the state.  Beyond this, an approaching surface ridge will work to bring the state some much needed sunshine for the latter part of the weekend.

Short-term (Now through Overnight Friday into Saturday)

Currently, the state is under the influence of a moderately tight (moderate in comparison to Sandy) pressure gradient that is forcing a mean westerly wind across the state. This will help influence gravity wave clouds over the ridges, but more importantly, lake effect precipitation over northwestern portions of the state.  Erie is already seeing some lake effect rain, something that only the 12z 4km Nam was able to resolve. Based on its resolution, the most intense lake effect showers will occur along the eastern coast of Lake Erie, with 850 winds helping to extend light showers all the way to Central PA. Overnight Thursday into Friday, scattered light showers will fall along the sloping edges of the ridges leading up to State college, and then dissipating later in the night as clouds become broken. Friday will show the heaviest lake effect rain in Erie and near Bradford, but areas south and east of them will see lighter showers during the afternoon.  With the 540 dam line far to our south by then, a viewing of the forecasted soundings show us the potential for mixed precip further away from the lake, with potential for that occurring overnight tonight into Friday for parts in the Northwest, North Central, Ridge/Valley, and Laurel Highland regions. Squall lines perpendicular to the ridges are being resolved for overnight Saturday, but with no convergence of surface winds and NVA, that could end up being just scattered showers along southwestern PA. the east side of the state will enjoy no precip the mean downsloping wings will favor cloud breaking for Friday, with decreasing clouds Saturday as the trough pushes away as well as a weakening surface pressure gradient.  

Long-Term (Saturday through Monday)

With the trough aloft receding in conjunction to an approaching surface high, the cloud fraction over eastern PA will decrease as the day rolls along. The influence of lake effect will diminish with weakening surface winds, but the will still be enough energy both in the trough aloft and with the onshore flow to allow for mostly overcast cloudswithin Western PA. as the ridge slowly weakens the pressure gradient, the presence of sun will be felt statewide by Sunday, with more clearing and sun for Monday.

During this time, positive vorticity will get cutoff from the trough aloft and sink toward the south, leading into the development of a potential Nor'easter looking to make landfall next Wednesday. The 12z GFS throws it into New England, but the 12z Euro  throws it into us, so keep a watchful eye on the models as we look toward next week!