Area Forecast Discussion
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FXUS61 KPBZ 190858
AFDPBZ

Area Forecast Discussion
National Weather Service Pittsburgh PA
358 AM EST Thu Jan 19 2017

.SYNOPSIS...
A short break from precipitation today as high pressure slides
across the area. Rain will return to the region late tonight and
Friday as the next upper level system moves through. Mild pattern
continues through the weekend.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...
Upper level heights will quickly rise today in response to
deepening 500mb low swinging through the central US. Closer to the
surface, warm air advection will get under way and a weak surface
high will move across Pennsylvania. The toughest part of the
forecast is how fast, if at all, the low clouds will finally
disperse from the area. As new model data arrives, it is becoming
less and less likely that low cloud deck will leave the area until
very late in the day. The saturated layer will decrease in depth,
but forecast soundings show the inversion remaining until at
least the mid to late afternoon. This will have an effect on our
highs today, which have been lowered a bit. Still temperatures
will reach 5 to 10 degrees above normal.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY/...
Latest models are coming into good agreement on slowing down the
onset of rain tonight, as the upper level low over the Central US
will weaken and spin further to the north by Friday morning.

An elongated warm front will swing through the area late tonight
and Friday morning as a series of shortwaves, on the extremity of
the main trough, rush through Friday morning. Have slowed the
onset of showers from the previous forecast and have also brought
a faster end to the precipitation Friday afternoon. By Friday
afternoon, the main moisture stream will have moved to the
northeast, with the trough axis following closely on its heels.

Warm air advection will continue Friday night and Saturday as the
flow from the southwest strengthens. Forecast soundings are
indicating the atmosphere slowly drying out Saturday, which will
allow for some decrease in cloud cover. Temperatures Saturday will
be 20 to 25 degrees above normal.

&&

.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
A strong upper low will develop over the Southern Plains Sunday and
track eastward into early Monday, before turning toward the
northeast Monday night and Tuesday. Ensembles are in descent
agreement with the timing of this system, so a blend of guidance
will be used for the extended period. Temperatures will remain
above normal through the period.

&&

.AVIATION /09Z THURSDAY THROUGH MONDAY/...
IFR cigs will persist overnight into early Thursday morning as
weak high pressure builds across the region. By mid morning low
levels should mix out to allow for VFR. West winds near 10 KTs
tonight will become light and variable.

.OUTLOOK...
Restrictions are likely with low pressure Friday, and again on
Sunday.

&&

.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...None.
OH...None.
PA...None.
WV...None.

&&

$$


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