Area Forecast Discussion
Issued by NWS State College, PA
Issued by NWS State College, PA
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268 FXUS61 KCTP 021648 AFDCTP Area Forecast Discussion National Weather Service State College PA 1248 PM EDT Sun Jun 2 2024 .SYNOPSIS... A southwesterly flow of increasingly moist air ahead of weak low pressure over the Great Lakes region will bring showers today across the Western Mountains of the state with scattered mid to late afternoon showers possible across the Central Mountains and Susquehanna Valley. It will turn warmer with moderate humidity Monday and Tuesday along with an isolated shower or thunderstorm possible in the afternoon and evening. A slow moving cold front will cross the region during the middle of the week bringing the best chance for rain/storms, then an upper level trough will build over the region late week into next weekend with more unsettled weather expected. && .NEAR TERM /THROUGH TONIGHT/... Clouds will gradually thicken up and lower to under 8 KFT AGL across the Western Mtns late this morning, across the Central Mtns early this afternoon, and east of the Susq Valley late in the afternoon/early this evening. PWATS will rise from 0.5 to 0.7 inches this morning to between 1.25 and 1.5 inches this afternoon. As such, rain showing up on radar may not necessarily equate to rain reaching the ground through the morning hours. Additionally, very little low level convergence is present within the warm sector spread across our region, nor is there any significant larger scale deep layer forcing beneath the favorable quads of a jet. As such, precipitation amounts should be light. HREF 12 hour amounts ending at 00Z or 06Z Monday are generally under 0.10" with a few spotty 0.20" + amounts possible across Central and Western PA. MU CAPE is mainly under 250 J/KG later today and tonight, however, 925-850 mb based LIs are about -1C over Southern PA from 22Z today to 05Z Sunday. So a rumble of thunder can`t be ruled out from isolated/embedded low- topped TSRA. High temps this afternoon (before any -SHRA move in from the west) will vary from the upper 60s to low 70s across the higher terrain of Northern and Western PA. to around 80 in the Southeast. Surging dewpoints overnight will be a sign of more moisture in the air. For locations that get precipitation today and see some clearing overnight, patchy fog will be possible. Low confidence in fog coverage based on uncertainty with overnight cloud cover, but can`t rule out some instances of valley fog on Monday morning. Lows will range from the mid 50s in the northwest to low 60s southeast. && .SHORT TERM /MONDAY THROUGH WEDNESDAY/... A very weak cold frontal boundary will push south across the state early in the period before washing out as it nears the Mason/Dixon line on Monday. Building upper level ridge to 580dm should favor lower POPs Mon-Tue. However, the airmass will be trending warmer and more humid with just a bubble of weak sfc high pressure drifting from Lake Ontario on Monday to the New England Coast by early Tuesday. As a result, we can`t rule out spotty diurnally driven convection. Have gone with isolated wording for shower/storm potential as pinning down the exact location of storms is difficult in this type of pattern. High temps both Monday and Tuesday will range from the mid 70s across the highest elevations of the North and West to the low- mid 80s in the Southern Valleys. && .LONG TERM /WEDNESDAY NIGHT THROUGH SATURDAY/... Low pressure passing well to the north of the state in the latter part of the week will push a cold or occluded front thru most likely on Thursday. The upper feature driving this sfc feature is a deepening closed low. The weak moisture plume in advance of the front will result in mainly light precip. If we can manage to break into the warm sector, we should have some thunder Wed night and Thursday. Ensemble plumes suggest most likely areal average rainfall Wed- Thu is around a half inch with near zero chances of 1"/24hrs time (20pct). After the front passes, the rest of the long range period will be dominated by the big closed low. It is almost cutoff, but does inch eastward with time. Some guidance (incl Op GFS) has the center of the upper low cross NY/PA over the weekend. That would make a very showery time with mainly aftn TS/SHRA and limited heating. However, 8H temps won`t be too chilly, running just one std dev to the left (colder) for June. && .AVIATION /18Z SUNDAY THROUGH FRIDAY/... Mid and high clouds thickening up, but barely any rain, and not flight restrictions, are occurring as of yet over the airspace of central PA. DUJ and IDI are into MVFR right now (16Z), but not any farther east. As we moisten up, a brief reduction into MVFR is possible before sunset over the west (BFD, JST). Some fog and lower CIGS will be possible late, mainly across the west. However, without much rainfall, it would be northwest flow just aloft and the resultant upslope that might create lowered cigs/vis overnight. Will keep mentions rather tame (higher-end IFR) without tanking them (V/LIFR). Outlook... Mon...Patchy AM fog, slight chance of PM t-storms. Tue-Thu...SHRA and TSRA at times with restrictions possible. && .CLIMATE... Prelim May and Spring 2024 Temperature & Precipitation Rankings Harrisburg: T12th warmest; 76th driest May T3rd warmest; 33rd wettest Spring Williamsport: 9th warmest; 22nd wettest May 4th warmest; 11th wettest Spring Altoona: 9th warmest; 13th wettest May 2nd warmest; 3rd wettest Spring Bradford: 4th warmest; 36th driest May Warmest; 21st wettest Spring && .CTP WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...Lambert NEAR TERM...Lambert/Banghoff SHORT TERM...Lambert LONG TERM...Dangelo AVIATION...Dangelo/Martin CLIMATE...Steinbugl