Area Forecast Discussion
Issued by NWS State College, PA
Issued by NWS State College, PA
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285 FXUS61 KCTP 021606 AFDCTP Area Forecast Discussion National Weather Service State College PA 1206 PM EDT Thu May 2 2024 .SYNOPSIS... -Warm/dry weather with lower humidity continues for today and most or all of Friday -Trending unsettled into the weekend with some periods of rain and thunderstorms Sat/Sun && .NEAR TERM /UNTIL 10 PM THIS EVENING/... The only cu that have popped thus far are over far srn Somerset Co. Dewpoints are dropping across most of the area, but still holding in the u50s in the SE. Still expecting those to dip a little, too. Fcst rolling along nicely. Prev... Tranquil conditions with mainly clear skies cover the entire forecast area early this morning. Surface T/Td spreads of several deg F or more are negating any notable valley fog development. Temps to start the day will be close to 10 degrees above climo in the warm advection regime ahead of a weak/dry cold front front that was sliding across the NW Mtns of PA at 09Z. Daybreak readings will range from 45F to 50F throughout the higher rural valleys of Central PA, to the mid and upper 50s across the Lower Susq Valley. The aforementioned weak cold front will bring primarily a few to several deg F drop in sfc dewpoints today, yielding another excellent vsby day with abundant sunshine. This frontal boundary will settle just south of the Mason Dixon Line by this afternoon as the associated shortwave passes off the New England Coast and upper level ridging sharpens and crests over PA tonight. Vertical mixing of model 850mb temps in the 12-14C range will equate to highs ranging from the mid 70s over the N Mtns, to the mid 80s in the Southern Valleys, which are 10-15 degrees higher than what we normally see for early May. A nearly east/west band of low level convergence and higher humidity is depicted via the latest HREF near the Mason/Dixon line this afternoon yielding MU CAPE values of a few to several hundred j/kg. A weak capping inversion and very dry air above 800mb suggests any convection is very unlikely there. The very dry air above the weak inversion aloft supports undercutting NBM dewpoints this afternoon over the central and northern part of the forecast area. We continued to employ a blend of the NBM and the much lower numbers obtained from the MixedDewpoint Tool. && .SHORT TERM /10 PM THIS EVENING THROUGH 6 PM FRIDAY/... Sfc and upper level ridge of high pressure will remain over PA for most or all of the daylight hours Friday. Clouds will increase across the Western part of the CWA later Friday afternoon, bringing the chance of a few showers near and to the west of the RT 219 corridor after 21Z Friday. Southeasterly flow will develop across much of the CWA Friday as the center of sfc high pressure exits stage right off the Mid Atlantic Coast. This will lead to cooler daytime highs - mainly in the mid to upper 70s. && .LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/... A frontal boundary will slowly make it`s way eastward from the Midwest across the Commonwealth this weekend, accompanied by showers and storms. The best chc of wet weather will be across western PA Fri night, before expanding eastward Saturday into Sunday. Looking to the first half of next week, the front should pull east of the region on Monday, taking the widespread shower/storm activity with it. Tuesday into Wednesday, a warm front approaching from the Ohio Valley should bring an increasing chc of showers/storms. && .AVIATION /16Z THURSDAY THROUGH MONDAY/... A weak area of low pressure passing to our north has pushed a weak/dry cold front into srn PA. The front shouldn`t move too much more to the south today. An upper ridge will crest overhead, keeping the sky clear, except for a few cu, mainly in the Laurels. WNW sfc winds are already gusting into the teens. Tranquil weather will persist through tonight with diminishing winds thanks to the high pressure aloft and to our NE. Expect a return/srly flow to develop in the morning on Friday. This will help generate more cu, and decrease stability, esp in the W. SHRA/TSRA are expected late aftn/evening Friday at JST and BFD. A warm front will rise into wrn PA on Friday, but stall out there until Sat when a cold front catches up and pushes it eastward. This will push the SHRA/TSRA to the east and across the rest of Central PA. Widespread SHRA/TSRA are expected Friday night into Sunday. The heaviest rain will be Fri night over the W and Saturday aftn/evening in the SE. IFR restrictions will be possible Fri PM into Sunday. Outlook... Sat PM-Sun...Widespread restrictions across the central and western mountains due to low cigs. SHRA likely with a chance of TSRA. Mon-Tues...AM fog/clouds poss. PM -SHRA possible areawide. && .CLIMATE... Near-record highs are forecast for some locations in south central PA this afternoon. The daily records are listed below. Harrisburg88 in 1913 Altoona87 in 1954 State College86 in 1938 && .CTP WATCHES/WARNINGS/ADVISORIES... None. && $$ SYNOPSIS...Dangelo NEAR TERM...Dangelo SHORT TERM...Lambert/Fitzgerald LONG TERM...Gartner/Evanego AVIATION...Evanego/Colbert CLIMATE...Steinbugl