Scientific Forecaster Discussion

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Area forecast discussion 
National Weather Service Pittsburgh PA
1220 PM EDT Monday Apr 21 2014

Synopsis...
high pressure will maintain dry and warm condtions today...but
showers will accompany a Tuesday cold front.

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Near term /through Tuesday/...
no major alterations were needed for the early afternoon update as
insolation and light wind spprt a temperature increases well into the 70s.

Clouds will be on the increases tonight as an upper trough...cold front approach. Limited...and
short lived dynamics are expected to spprt a bout of showers during
the morning. Latest NAM continues to indicate some weak instability aftr
daybreak...thus have added a slight thunder mention for the eastern
half of the County Warning Area for a cpl of hours. Quantitative precipitation forecast undr this
scenario is projected at a tenth to quarter inch.

Near term temperatures were forecast using the latest lamp guidance.

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Short term /Tuesday through Thursday/...
Tuesday showers will diminish during the afternoon given current timing of
front...and middle level trough progression. With morning timing and lack
of consistent low level instability prognosis...have maintained
shower wording only.

Cold advection via northwest flow should maintain stratocu clouds and possibly
a stray shower into Tuesday night. Building high pressure will suppress those
parameters later on Wednesday and into Thursday.

Post frontal temperatures are forecast about 10 degrees undr the avgs...but
quick moderation back to the seasonal norms is expected on Thursday.

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Long term /Thursday night through Monday/...
another cold front is timed for a Friday approach and passage as upper low
develops across the Great Lakes and toward eastern Canada by the weekend.
Likely probability of precipitation were thus included with the front...and chance probability of precipitation were
maintained into the weekend alng with cool temperatures.

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Aviation /16z Monday through Friday/...
VFR and light S...to SW wind can be expected through tonight...but
deterioration to genl MVFR should be anticipated on Tuesday morning
as a cold front approaches the upper Ohio region. Cold advection in the wake of the
bndy will maintain stratocu...isolated showers...and restricion potential
into Tuesday night.

Outlook.../Tuesday night through Friday/...
VFR will quickly rtn with middle week high pressure...but showers and
restriction potential are anticipated with a Friday cold front.

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Pbz watches/warnings/advisories...
Maryland...none.
Ohio...none.
PA...none.
WV...none.

&&

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