Area Forecast Discussion
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000 FXUS61 KPBZ 010603 AFDPBZ AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PITTSBURGH PA 203 AM EDT FRI MAY 1 2015 .SYNOPSIS... SCATTERED SHOWERS ACROSS THE REGION WILL DISSIPATE BY DAYBREAK. LOCATIONS EAST OF PITTSBURGH MAY SEE SHOWERS DEVELOP AGAIN THIS AFTERNOON. TEMPERATURES WILL BE NEAR NORMAL. && .NEAR TERM /THROUGH TODAY/... SCATTERED SHOWERS CONTINUE TO WRAP AROUND THE UPPER LOW NOW CENTERED NEAR ROANOKE. RAINFALL RATES HAVE DROPPED OFF FOR THE MOST PART AND LATEST RAPID UPDATE MODEL PROGS INDICATE PRECIPITATION SHOULD CONTINUE TO DIMINISH OVER THE NEXT SEVERAL HOURS...BEFORE DAYBREAK. NO MAJOR UPDATES ARE NEEDED AT THIS TIME. PREV DISCUSSION FOLLOWS.. THE SLOW-EVOLVING DEFORMATION FIELD AROUND THE UPPER LOW THAT SEEMS TO BE DRIVING INTO THE BASE OF THE LONG WAVE TROUGH OVER THE APPALACHIANS IS ALLOWING FOR MUCH MORE MOIST AIR TO INFILTRATE WESTWARD ACROSS THE MOUNTAINS OF CENTRAL PENNSYLVANIA INTO METRO PITTSBURGH AT THIS HOUR. SATELLITE IMAGERY INDICATES SUBSTANTIAL CLOUD TOP COOLING IN THIS BAND...AND RADAR SIGNATURES REVEAL A FAR BIT OF MESOSCALE FORCING IS LIKELY GOING ON WITHIN THIS BAND. A NICE MESOLOW IS EASILY DIAGNOSED OVER SOMERSET COUNTY AS OF 8 PM...AND IS HELPING TO ACCENTUATE PRECIPITATION RATES WITHIN THE BAND OF RAINFALL OVER ITS LOCALE. THIS WHOLE FIELD WITH MESOSCALE- INDUCED HEAVIER RAINFALL AND EMBEDDED CONVECTION WILL MIGRATE WEST AND SOUTHWARD THROUGH THE REMAINDER OF THE EVENING AND INTO THE OVERNIGHT...LIKELY DROPPING ONE HALF TO THREE- QUARTERS OF AN INCH OF ADDITIONAL RAINFALL AS IT DOES. CONDITIONS SHOULD IMPROVE FRIDAY AS DEEPER MOISTURE EXITS AND CONVERGENCE ALOFT ENTERS THE PICTURE. THIS SHOULD ALLOW FOR A GOOD DEAL OF CLEARING OUT BY AFTERNOON EVERYWHERE EXCEPT THE RIDGES. FRIES && .SHORT TERM /TONIGHT THROUGH SUNDAY/... HEIGHTS WILL BEGIN TO RISE SATURDAY AS A SHORTWAVE RIDGE ALOFT BUILDS ACROSS THE REGION. DRY WITH A GRADUAL WARMING TREND AS TEMPERATURES WILL WARM TO MORE THAN 5 DEGREES ABOVE AVERAGE SUNDAY. && .LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/... HIGH PRESSURE WILL REMAIN IN CONTROL THROUGH MONDAY AS TEMPERATURES WARM TO ABOVE NORMAL LEVELS. MODELS DIFFER IN SOLUTIONS CONCERNING THE MOVEMENT OF A FRONT TUESDAY AND WEDNESDAY. LATEST GUIDANCE PUSHES FRONT A BIT FARTHER SOUTH AND POPS WERE BROUGHT FURTHER SOUTH. WARM THROUGH THE PERIOD AS UPPER LEVEL RIDGE BUILDS ACROSS THE SOUTHEAST U.S. && .AVIATION /06Z FRIDAY THROUGH TUESDAY/... DIFFICULT OVERNIGHT FORECAST WITH A DIMINISHING AREA OF SHOWERS SWINGING SOUTHWESTWARD THROUGH SOUTHERN PORTS. IFR/MVFR CIGS ARE NOT AS PREVALENT AS FIRST THOUGHT...AS THEY SEEM TO BE CONFINED TO THE AREA JUST AHEAD OF THE SHOWERS AND WESTWARD. WITH SUCH A CLOSE TEMPERATURE DEWPOINT SPREAD AT ALL SOUTHERN PORTS...WILL NEED TO KEEP IN THE POSSIBILITY OF IFR CIGS FOR A TIME EXCEPT FKL AND DUJ. DESPITE OF THIS...EXPECT MOST PORTS TO REMAIN GENERALLY VFR FOR THE OVERNIGHT. ONCE THE SHOWERS EXIT...DRIER AIR BEHIND THE PRECIPITATION WILL ALLOW FOR A CONTINUATION OF THE VFR CONDITIONS. AFTER SUNRISE...A VFR FORECAST FOR THE REMAINDER OF THE DAY WITH THE POSSIBILITY OF CU DEVELOP WITH DAYTIME HEATING. .OUTLOOK.../FRIDAY NIGHT THROUGH TUESDAY/... VFR IS EXPECTED THROUGH THE WEEKEND. SOME RESTRICTIONS ARE POSSIBLE AT SOME TERMINALS LATE MONDAY AND TUESDAY. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$

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