Area Forecast Discussion
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000 FXUS61 KPBZ 180817 AFDPBZ AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PITTSBURGH PA 417 AM EDT MON AUG 18 2014 .SYNOPSIS... LOOKS TO BE AN ACTIVE WEEK AHEAD AS A SERIES OF DISTURBANCES CROSS THE REGION. && .NEAR TERM /UNTIL 6 PM THIS EVENING/...
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A STALLED DEWPOINT BOUNDARY...A QUASI-STATIONARY FRONT...AND A WEAK SURFACE LOW WILL BE THE MAIN FOCUS FOR WEATHER TODAY. THE DEWPOINT BOUNDARY IS STRETCHED ACROSS THE SOUTHERN THIRD OF MY FA. THE BOUNDARY IS NOTICEABLE BY DEWPOINTS IN THE MID 60S TO THE SOUTH OF IT AND LOW TO MID 50S TO THE NORTH. THE STATIONARY FRONT WILL SIT OVER THE MID-ATLANTIC REGION AS A SURFACE WAVE MOVES EASTWARD ALONG IT. THERE WILL BE SOME INTERACTION BETWEEN THE EASTWARD MOVING LOW AND THE OHIO VALLEY BOUNDARY THIS AFTERNOON. THIS WILL MEAN THE RISK FOR SHOWERS AND STORMS AS THE WEAK SURFACE WAVE MOVES THROUGH WV. MOST OF THE UPPER LEVEL SUPPORT TODAY WILL REMAIN OVER THE MID-ATLANTIC REGION. HOWEVER...ATMOSPHERE WILL DESTABILIZE IN THE HUMID AIR SOUTH OF THE BOUNDARY AND THERE WILL BE A NOTICEABLE INCREASE IN LOW LEVEL MOISTURE CONVERGENCE AND FORCING. WILL KEEP POPS OVER THE SOUTHERN THIRD OF THE AREA...WITH THE HIGHEST ACROSS THE RIDGES. BIG DIFFERENCE IN AIR MASS FROM THE FAR TO NORTH TO FAR SOUTH TODAY. ACROSS THE NORTH SEASONABLE AND COMFORTABLE CONDITIONS. ACROSS THE SOUTH...SEASONABLE TEMPS BUT RATHER HUMID.
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&& .SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY/... AFOREMENTIONED SURFACE WAVE WILL CONTINUE ON ITS EASTWARD TREK TONIGHT ALLOWING FOR ACTIVITY ACROSS THE SOUTH TO DISSIPATE. FRONT WILL REMAIN STALLED TO THE SOUTH AND SHIFT NORTHWARD TUESDAY AS THE NEXT UPPER LEVEL WAVE MOVES ACROSS THE MIDWEST. WAVE WILL REACH FORECAST AREA LATE TUESDAY. MODELS ARE HINTING THAT AN MCS COULD DEVELOP TUESDAY AFTERNOON TO THE WEST AND MOVE EASTWARD OVER THE UPPER OHIO VALLEY TUESDAY EVENING. WILL INCREASE POPS DURING THIS TIME PERIOD. WITH AN OVERALL SLOW MOVING PATTERN...SHORTWAVE WILL TAKE MOST OF TUESDAY NIGHT TO CLEAR THE AREA. VERY LITTLE CHANGE TO THE OVERALL PATTERN WEDNESDAY AS ANOTHER WAVE WILL EVENTUALLY SWING THROUGH. TIMING AT THIS POINT IS A LITTLE TRICKY DUE TO DIFFERENCE IN DETAILS BETWEEN MODELS...BUT EXPECT MORE CONVECTION TO DEVELOP ON WEDNESDAY. && .LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/... VERY LITTLE CHANGE IN OVERALL PATTERN THROUGH THE LONG TERM. ZONAL FLOW WITH A SERIES OF SHORTWAVES BRINGING THE RISK FOR SHOWERS AND STORMS. STILL SEEING MODEL INCONSISTENCIES THROUGH THE WEEKEND... SO FORECASTING TIMING AND LOCATION OF ACTIVITY IS DONE WITH LOW CONFIDENCE. && .AVIATION /08Z MONDAY THROUGH FRIDAY/... HIGHLY VARIABLE AVIATION CONDITIONS CAN BE EXPECTED ACRS THE UPR OH VALLEY THIS MRNG WITH NRLY STATIONARY FRONT IN VCNTY OF THE I 70 CORRIDOR AND LOW PRES MOVG ACRS THE MID ATLANTIC REGION SPEWING MID LVL MSTR ACRS ITS NRN FLANK. RESULTING CLDS SHOULD PRECLUDE IFR FOG FOR PORTS IN VCNTY OF PIT...BUT LLVL MSTR POOLING ALNG THE FRONTAL BNDRY IS LIKELY TO RESULT IN IFR ESPECIALLY NR MGW. MORE IFR IS ANTICIPATED AT FKL AND DUJ WHERE THE SKY HAS CLEARED/SCTD OVR A MOIST SFC LYR. GENERAL VFR IF FORECAST AFTR DAYBREAK...WHICH MAY BE MARRED BY SCT SHWRS NR PORTS S OF PIT. OUTLOOK.../TONIGHT THROUGH FRIDAY/... SEVERAL CROSSING DISTURBANCES WILL CAUSE PERIODIC RESTRICTIONS THROUGH FRIDAY. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$

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