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Next 12 Hours

Forecast data from the National Digital Forecast Database.

5 Day Forecast

• Wednesday
• 
• High: 79 °
• Low: 57 °
• Partly Cloudy

• Thursday
• 
• High: 81 °
• Low: 59 °
• T-Storms

• Friday
• 
• High: 86 °
• Low: 64 °
• Chance of T-Storms

• Saturday
• 
• High: 88 °
• Low: 59 °
• Fog

• Sunday
• 
• High: 86 °
• Low: 64 °
• Chance of T-Storms

Area forecast discussion 
National Weather Service Pittsburgh PA 
1025 am EDT Wednesday may 23 2012 


Synopsis... 
a weak upper level low will meander over the Middle Atlantic States 
and support the chance for afternoon showers and thunderstorms 
storms for the next couple of days. 


&& 


Near term /through tonight/... 
no major changes needed for the late morning update. 


Stalled surface front was analyzed east of the ridges this morning while 
weak upper flow was split around broad low pressure centered over the 
southeastern states. 


While the front and deeper moisture has been pushed further 
south, weak low pressure moving alng the boundary should push it westward 
again this afternoon. With trough aloft resulting in relatively 
low convective temperatures...scattered storms are forecast over areas 
south and east of Pittsburgh. 


Given the weak wind field...convective activity will fade this 
evening as temperatures fall below those convective thresholds. 


&& 


Short term /Thursday through Saturday/... 
the upper low center is finally prognosticated to drift northward on 
Thursday...and diurnally supported rain showers/thunderstorms and rain will again be possible. 


For Friday...models are projecting a strong shortwave across the 
northern lakes...but differ in handling of the surface front with the 
latest GFS progging the more dramatic southward advance to near 
the Interstate 80 corridor. Either way...outflow from convection 
over the lakes may plow into the destabilizing airmass over the 
upper Ohio Valley region during the afternoon/eve. Slight probability of precipitation...with 
chance numbers from pit northward will be maintained as will 
vigilance of the wind field as marginal deep layer shear values 
currently look marginal for severe weather over areas north of I 80. 


By Saturday...building ridge aloft will Herald diminishing precipitation 
chances and much warmer temperatures...with highs currently 
projected about 15 degrees above the seasonal normals. 


&& 


Long term /Saturday night through Tuesday/... 
hot...near 90 degree...weather can be expected for the remainder 
of the Holiday weekend with only isolated thunderstorms possible 
in the late afternoon warmth. By Tuesday...current timing suggests 
that shortwave energy/quickening flow will erode the ridge and 
support the next chance for more widespread storm chances...as 
well as somewhat cooler temperatures. 


&& 


Aviation /15z Wednesday through Sunday/... 
potential for scattered showers and thunderstorms will be limited 
to kmgw/klbe and locations eastward this afternoon. Thus, no 
mention in the tafs at this point. 


Outlook...Thursday through Sunday... 
isolated to scattered showers are possible from the late afternoon 
into the evening hours on Thursday and Friday as low-level 
moisture persists and a stalled upper level system remains over 
the region. MVFR and patchy IFR visibility restrictions in fog are 
possible at most Airport locations during the early morning hours 
Thursday through Saturday. 


Although an isolated shower or thunderstorm with localized 
restrictions cannot be ruled out on Saturday, mostly VFR 
conditions will prevail across the terminals for the weekend as 
high pressure aloft builds into the area from the southwest. 


&& 


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


&& 


$$