Area Forecast Discussion
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459 FXUS61 KPBZ 222208 AAA AFDPBZ Area Forecast Discussion...UPDATED National Weather Service Pittsburgh PA 608 PM EDT Mon May 22 2017 .SYNOPSIS... High pressure will provide a dry Tuesday with seasonal temperatures. Unsettled weather for the remainder of the week. && .NEAR TERM /THROUGH TUESDAY/... 610pm update...only change to the overnight period was an increase in cloud cover. First cirrus cloud shield will exit to the east this evening. This cloud deck will be quickly replaced by a second area of cirrus clouds before dawn. Previous discussion... Diurnal clouds will go bye bye with sunset leaving passing mid and high clouds the balance of the night. With good drying at the surface courtesy of dewpoints in the lower 40s, this should be enough to negate fog development outside of deeper West Virginia gorges. Any morning fog will burn off to what will be best weather day of the week. High pressure yields abundant sunshine with daytime fair weather cumulus once temperatures climb into the mid and upper 60s /convective threshold/. West Virginia and western Maryland will see more mid and high clouds creating a more pessimistic forecast. Elected to keep a small pops for the higher terrain however, recent runs have backed off on the amount of low level moisture thus QPF if it happens will be a few hundredths as best. The mercury will go a few degrees beyond what was experienced today as H8 temps climb 2C from today`s values equating to widespread lower and mid 70s for maximum temps. The bias corrected consensus raw guidance was used for max and min temps. && .SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY NIGHT/... Anomalously deep mid level cyclone moves slowly east with outer band of showers reaching parts of eastern Ohio by late morning then taking its sweet old time before reaching western Pennsylvania and northern West Virginia toward supper time. With plenty of moisture in the column, do not expect to see any convective activity as it moves through. Under heavy showers due to the slow northward propagation and easterly wind component /upslope/, far eastern areas may see rainfall amounts approach an inch. Otherwise, look for a half inch less through Wednesday night. The occluded mature system oozes eastward Thursday with the warm conveyor belt spreading more showers across the region during the day. GFS is more optimistic than the NAM with the plume of showers residing in central Pennsylvania and us under a dry slot. With the difference being only a few hundred miles and given the numerical NCEP suite struggles with these systems, low confidence in the forecast for this time period, however somewhere its going to rain so continued with likely pops. H5 low continues to move east Thursday night, however BUFR soundings show still portray a lot of moisture so clouds will hang tough. Wrap around showers will continue, but rain rates won`t be as high. && .LONG TERM /FRIDAY THROUGH MONDAY/... Highlights: - Active weather regime - Temps right where they should be - Memorial Day Weekend BBQ plans? Monitor forecast! The weather pattern remains active right through the long term as a series of system traverse the region making people dodge rain drops this upcoming holiday weekend. The long term starts out quiet with a transitory surface anticyclone Friday, however that is quickly shunted off to the east by an incoming mid level shortwave trough. The aforementioned shortwave trough is slated to arrive Saturday night into Sunday. Still timing differences as one would expect this far out, but whenever it passes expect a several hour period of showers and perhaps thunderstorms. Precipitable water peaks around 1.5" and with 30 to 40 kts of flow, therefore high water does not appear a concern at this juncture. Severe weather threat is low as well given uncertainty with the timing. If it passes during peak heating hours, there would be a low threat for damaging winds. High pressure builds is forecast to build in just time for Memorial Day. && .AVIATION /22Z MONDAY THROUGH SATURDAY/... VFR at all airports through Tuesday. Light east winds are forecasted through the period. .Outlook... The next chance for widespread restrictions and precipitation is expected Wednesday night into Thursday. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...None. OH...None. PA...None. WV...None. && $$ is the U.S. government's official web portal to all federal, state and local government web resources and services.