Area Forecast Discussion
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000 FXUS61 KPBZ 210929 AFDPBZ AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PITTSBURGH PA 529 AM EDT SUN SEP 21 2014 .SYNOPSIS... A COLD FRONT WILL BRING SHOWERS AND THUNDERSTORMS TODAY. HIGH PRESSURE WILL DOMINATE THE REMAINDER OF THE WEEK WITH DRY WEATHER. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... STILL CONCERNED OVER THE POTENTIAL FOR STRONG TO SEVERE STORMS LATE TODAY WITH THE PASSAGE OF A COLD FRONT. WIND FIELD IS IMPRESSIVE AND THE ATMOSPHERE DESTABILIZES AHEAD OF THE BOUNDARY. NAM IS CLEARLY THE STRONGEST WITH MESOSCALE FEATURES COMPARED TO OTHER OPERATIONAL MODELS. THIS LEADS ME TO BELIEVE THAT THE NAM MAY BE ON ITS OWN WITH ITS DEPICTION OF THE SITUATION SO WILL LEAN AWAY FROM IT. ANY CONVECTION THIS AFTERNOON WILL HAVE THE POTENTIAL TO PRODUCE GUSTY WINDS. WITH MIXING HEIGHTS RISING AHEAD OF THE FRONT...COULD STILL SEE STRONGER WIND GUSTS WITHOUT CONVECTION. OTHER LIMITING FACTORS WILL BE CLOUD COVER AND THE RISK FOR SCATTERED SHOWERS THIS MORNING. FOR A NAM SOLUTION TO COME TO FRUITION...WOULD NEED TO SEE CONVECTION FIRE AND GROW OVER THE GREAT LAKES ALONG THE FRONT AND THEN SUSTAIN ITSELF...THANKS TO THE HIGH SHEAR VALUES IN ITS SOLUTION. THE OTHER OPERATIONAL MODELS ARE NOT IN TOTAL AGREEMENT WITH THIS SCENARIO. FORECAST WILL SHOW SHOWERS THIS MORNING AND THEN SHOWERS/STORMS THIS AFTERNOON RIGHT ALONG THE FRONT. HAVE INCREASED WIND GUSTS DURING THE AFTERNOON. FRONT WILL PICK UP SPEED LATE THIS AFTERNOON AS STRONG SHORTWAVE TROUGH WILL DIG DOWN FROM THE WESTERN GREAT LAKES. && .SHORT TERM /6 PM THIS EVENING THROUGH TUESDAY/... SHOWER/STORM CHANCES WITH THE FRONT WILL END IN THE EVENING OVER THE SOUTH. STRONG CAA WILL FOLLOW ON THE HEELS OF THE BOUNDARY AS THE TROUGH AXIS MOVE THROUGH LATE SUNDAY NIGHT. 85H TEMPS WILL DROP SOME 6-8 DEGREES SUNDAY NIGHT AS THE FLOW VEERS TO THE NORTHWEST. EXPECT A LARGE AREA OF STRTOCU TO QUICKLY COVER THE REGION. ITS POSSIBLE...WITH THE COLDER AIR AND NORTHWEST FLOW... SHOWERS COULD REDEVELOP...PARTICULARLY OVER THE NORTH AND RIDGES. HEART OF THE COLD AIR SETTLES IN OVER THE REGION MONDAY. EXPECT THE STRATOCU DECK TO REMAIN IN PLACE. LATEST FORECAST SOUNDINGS ARE SHOWING A THIN LAYER OF SATURATION WHICH WOULD LIKELY PREVENT ADDITIONAL SHOWER ACTIVITY ON MONDAY. NOTICEABLY COLDER 85H TEMP FORECAST MONDAY COMPARED TO PREVIOUS RUNS. THIS WILL NECESSITATE THE LOWERING OF TEMPS ON MONDAY. IF LATEST MODEL OUTPUT IS CORRECT...HIGHS MONDAY COULD BE 15 TO 20 DEGREES BELOW NORMAL. COLD AIR WILL QUICKLY RETREAT TO THE NORTHEAST MONDAY NIGHT AS THE ENTIRE UPPER LEVEL SYSTEM SHIFTS TOWARD THE EAST COAST. WAA WILL KICK IN MONDAY NIGHT ALLOWING SKIES TO CLEAR. SURFACE HIGH AND RIDGING ALOFT WILL PROVIDE A SUNNY AND COMFORTABLE DAY TUESDAY. && .LONG TERM /TUESDAY NIGHT THROUGH SATURDAY/... DRY AND SEASONABLE PATTERN EXPECTED FOR THE LONG TERM. && .AVIATION /09Z SUNDAY THROUGH THURSDAY/... LINE OF SHOWERS WITH POSSIBLY A FEW ISOLATED THUNDERSTORMS PRECEDING A COLD FRONT APPROACHING FROM THE WEST WILL QUICKLY PASS ACROSS THE REGION THIS MORNING. UPSTREAM OBSERVATIONS SHOWS SEVERAL LOCATIONS MAY BRIEFLY DROP TO MVFR CIGS AS THE LINE PASSES BUT IMPROVE TO VFR SHORTLY THEREAFTER. THE ACTUAL COLD FRONT WILL PASS THROUGH THIS AFTERNOON...AND WHILE LATEST MODEL CONSENSUS INDICATES ONLY MARGINAL LIFT FOR THUNDERSTORMS...THERE IS POTENTIAL FOR STRONG WIND GUSTS OUT OF THE WEST WITH EITHER SHOWERS OR THUNDERSTORMS DURING FRONTAL PASSAGE. OUTLOOK.../MONDAY THROUGH FRIDAY/... STRATOCUMULUS BETWEEN 3-5KFT AGL WILL PERSIST THROUGH MONDAY...WITH VFR CONDITIONS EXPECTED THROUGH THE WEEK AS THE REGION REMAINS UNDER A DRY PATTERN. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$

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