Area Forecast Discussion
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000 FXUS61 KPBZ 140658 AFDPBZ Area Forecast Discussion National Weather Service Pittsburgh PA 158 AM EST Wed Feb 14 2018 .SYNOPSIS...
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A trough of low pressure will result in increasing rain chances today. Widespread rain is expected with a late Thursday and Friday cold front.
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&& .NEAR TERM /UNTIL 6 AM THIS MORNING/... Warm, moist advection and a nwd surging warm/dewpoint front should continue to result in clouds and minimal light rain chances overnight. Most of the radar returns N of I 80 are virga, with only ocnl very light precip reaching the ground. The cloud blanket and continued warm advection into the overnight should also hold temperature up - expect readings about 10 to 15 degrees above the averages. && .SHORT TERM /6 AM THIS MORNING THROUGH FRIDAY/... A relatively active short term period will be punctuated by one unfavorable upper level period from late Wednesday night into the early half of Thursday. Before this time, left exit region divergence will drive ascent with a passing wave Wednesday. Warm advection in the interim will maintain a column far too warm for anything but liquid precipitation, but forcing should be weak enough to preclude any problems from the rainfall. After the first wave passes, an interval in an unfavorable right exit of the jet with ample boundary layer moisture will yield a period of light rain and drizzle before rapid intensification of the upper flow starts to occur toward the end of the week. As this occurs, the upper jet will continue its eastward meander and yield a right entrance region of a roughly 185 kt 250 mb jet streak smack over our area. As such, rainfall rates will likely intensify going into Thursday overnight and Friday with a strong cold front sagging slowly through the area. This will be a period to watch going forward as local rainfall put upstream rainfall in WV may yield flooding problems. A flood watch was considered with this forecast, however after consultation, it was determined more consistency in the corridor of intense QPF was warranted. && .LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/... Rapidly drying and cooling conditions will move into the area from the northwest late Friday and Friday night. This will end the rain threat temporarily and bring a short period of snow in the post-frontal environment. High pressure will then control the area for a short time as cold as retreats and return flow allows temperatures to jump back above normal. The large scale pattern amplified greatly in the extended per the model consensus, with the mean upper trough centered in the western CONUS and rapidly strengthening Bermuda high off the coast allowing for deep upper southwesterly flow through the Mississippi Valley and into the northeastern U.S. This will mean subtropical moisture moving into the area next week with temperatures far above normal. && .AVIATION /07Z WEDNESDAY THROUGH SUNDAY/...
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MVFR cigs expected to develop near daybreak with increasing rain chances over the course of the day. Rain most likely mid- afternoon and through the evening...with IFR or lower restrictions based off of latest forecast soundings and analogs. .OUTLOOK... Widespread rain with cig/vis restrictions are likely with a late Thu/Fri cold front.
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&& .PBZ WATCHES/WARNINGS/ADVISORIES... MD...None. OH...None. PA...None. WV...None. && $$

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