Area Forecast Discussion
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000 FXUS61 KPBZ 061751 AFDPBZ AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PITTSBURGH PA 1251 PM EST FRI MAR 6 2015 .SYNOPSIS... HIGH PRESSURE WILL BUILD IN TODAY. A WEAK COLD FRONT IS EXPECTED LATE SATURDAY. && .NEAR TERM /THROUGH SATURDAY/... CLEAR SKIES AND A RELATIVELY STRONG INVERSION ALONG WITH FRESH SNOW ON THE GROUND ALLOWED FOR TEMPERATURE FREE FALL THIS MORNING. AN ALL TIME MARCH LOW TEMPERATURE RECORD WAS BROKEN AT PITTSBURGH...AND THE STAGE FOR THE REST OF THE DAY HAS THUS BEEN SET. LAYER RH VALUES ARE REALLY RATHER PALTRY...AND WILL FAIL TO DEVIATE MUCH THROUGH THE DAY AS SURFACE HIGH PRESSURE SLOWLY MEANDERS EASTWARD. THE GRADIENT WILL BEGIN TO INCREASE A BIT ALLOWING FOR SOME SOUTHWESTERLY FLOW BY THIS AFTERNOON...WHICH SHOULD START TO ALLOW FOR SOME MID AND UPPER LEVEL MOISTURE TO INCREASE BY THAT JUNCTURE. THAT SAID...ADVECTION IS LESS THAN IMPRESSIVE AND UPSTREAM SATELLITE VIEWS COINCIDE WITH THIS THINKING. A FEW CUMULUS MAY DEVELOP BASED UPON MODEL SOUNDINGS...PARTICULARLY GIVEN STRONG SUNSHINE THROUGH THE EARLY PART OF THE DAY. WITH ALL OF THAT IN MIND...A SUNNY TREND TOWARD PARTLY CLOUDY THROUGH THE DAY SHOULD BE EXPECTED. STRONG MARCH SUNSHINE SHOULD ALLOW FOR RATHER AGGRESSIVE TEMPERATURE RISES THROUGH THE DAY. MOS GUIDANCE SEEMED MUCH TOO LOW WHEN ACCOUNTING FOR THE STRONG MARCH SUN...SO HIGHS GENERALLY IN THE LOWER TO MIDDLE 20S WERE PROJECTED BY AFTERNOON. FRIES && .SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/... SYNOPTIC PATTERN IN THE SHORT TERM BEGINS WITH NORTHWEST FLOW ALOFT...AND MULTIPLE WEAK SHORTWAVE TROFS PASSING THROUGH THE GREAT LAKES. THIS WILL KEEP TEMPERATURES RELEGATED TO JUST BELOW AVERAGE THROUGH THE WEEKEND AND AT LEAST SLIGHT CHANCE POPS IN ALONG THE NORTH. DEEPER MID-LEVEL WAVE PASSING LATE SATURDAY NIGHT INTO SUNDAY MORNING WILL REINFORCE LOW-LEVEL MOISTURE POOLING SOUTH OF LAKE ERIE AND DAMMED UP AGAINST THE HIGHER TERRAIN TO OUR EAST. MEANWHILE...MOISTURE ABOVE 700MB IS TRANSIENT AND MOVES QUICKLY EAST OF THE AREA. THINKING THAT REALLY LIGHT SNOW WILL BE THE MAIN PRECIPITATION TYPE. BUT...WITH THE BULK OF THE MOISTURE CONFINED TO THE LOW-LEVELS AND THE TOP OF THAT MOISTURE AROUND -8C...THE POTENTIAL FOR FREEZING DRIZZLE EXISTS. STILL SOME UNCERTAINTY SURROUNDING EXTENT OF MOISTURE AND TIMING...SO CONFIDENCE NOT HIGH ENOUGH TO INCLUDE FREEZING DRIZZLE IN THE GRIDS. WILL NEED TO CONTINUE TO MONITOR THIS WITH FUTURE RUNS OF HIGHER-RES MODELS. FLOW BEGINS TO GO MORE ZONAL TOWARDS THE BEGINNING OF NEXT WEEK...ALLOWING TEMPERATURES TO MODERATE UNDER MOSTLY DRY CONDITIONS. TAX && .LONG TERM /MONDAY NIGHT THROUGH FRIDAY/... THE EXTENDED PERIOD LOOKS TO BE RELATIVELY QUIET AS ZONAL FLOW SETS UP ACROSS THE FORECAST AREA AND WE SEE A GRADUAL WARMING TREND IN TEMPERATURES...EXTENDING SLIGHTLY ABOVE NORMAL BY LATE WEEK. && .AVIATION /18Z FRIDAY THROUGH WEDNESDAY/... MAINLY VFR CONDITIONS ARE EXPECTED TODAY. CU RULE INDICATES JUST SOME SCATTERED DIURNAL CU FRIDAY AFTERNOON. SOUNDINGS ARE INDICATING THAT FKL AND DUJ COULD GO BROKEN IN THE AFTERNOON PROMPTING THE INCLUSION OF HIGH MVFR CIGS AT THESE PORTS. .OUTLOOK.../FRIDAY NIGHT THROUGH TUESDAY/... RESTRICTIONS ARE POSSIBLE THROUGH THE WEEKEND. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$

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