Area Forecast Discussion
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000
FXUS61 KPBZ 151734
AFDPBZ

Area Forecast Discussion
National Weather Service Pittsburgh PA
134 PM EDT Sun Apr 15 2018

.SYNOPSIS...
Rain will engulf the region today with the approach and passage
of a cold front.

&&

.NEAR TERM /THROUGH TONIGHT/...
Precipitation has only grudgingly made eastward progress this
afternoon, but this will change over the next few hours as the
approaching trough starts to take on a negative tilt and a moist
low-level jet starts to arrive.

Elected to expand the Flash Flood Watch to encompass eastern
Ohio and the northern WV panhandle. Model consensus of a band of
2 to 3 inch QPF was getting harder to ignore. The western
counties fall under the right entrance region of a 120-140 knot
upper jet during the late afternoon and evening as the trough
tilts. Layered frontogenesis and deformation will also be
present, along with anomalously high PWAT values of 1.3 to 1.4
inches. Instability still looks marginal overall, and have
maintained only a slight chance of thunder. If any storms can
root in the boundary layer, there is a short window where storms
could take advantage of long hodographs to allow for gusty
winds or a QLCS- type spinup. However, flooding possibilities
are the main concern.

The cold front will arrive in the western counties this evening
and depart to the east during the predawn hours. Steadier rain
will end, to be followed by more showery precipitation as the
upper low makes its way into the Ohio Valley.

&&

.SHORT TERM /MONDAY THROUGH WEDNESDAY/...
Upper troughing and cold, showery conditions are forecast to persist
through Tuesday, with shortwave ridging in advance of Plains low
pressure briefly modifying the situation for part of Wednesday.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH SATURDAY/...
The aforementioned Plains low is progged to cross the Great
Lakes and generate some showers late Wednesday with its cold
front before dropping temperature under the averages again for
the close of the week.

&&

.AVIATION /18Z SUNDAY THROUGH FRIDAY/...
Conditions will deteriorate to MVFR/IFR at all sites during the
evening hours. Thought that all sites would experience gusts
this afternoon, but in the 18Z TAFs pulled the mention of gusts
from any terminal that hadn`t had any so far. With a low level
jet present ahead of the cold front, have gone ahead and added a
period of low level wind shear to all TAFs, although LLWS will
likely occur for a shorter time period than is suggested in the
current forecast. Even with a wind shift with the cold frontal
passage, appears that conditions should remain MVFR at all
terminals into Monday afternoon.

OUTLOOK...
MVFR is anticipated for Tuesday as the area will remain under
an upper trough of low pressure. The next chance for restrictions
will come late Wednesday and Thursday as another front crosses
the area.

&&

.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...Flash Flood Watch through late tonight for MDZ001.
OH...Flash Flood Watch through late tonight for OHZ039>041-048>050-
     057>059-068-069.
PA...Flash Flood Watch through late tonight for PAZ020-021-029-031-
     073>076.
WV...Flash Flood Watch through late tonight for WVZ001>004-012-021-
     509>514.

&&

$$



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