Area Forecast Discussion
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000 FXUS61 KPBZ 281828 AFDPBZ AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PITTSBURGH PA 228 PM EDT SUN JUN 28 2015 .SYNOPSIS... SHOWERS AND COOL CONDITIONS WILL GREET THE NEW WEEK AS A PERSISTENT TROUGH OF LOW PRESSURE DEVELOPS OVER THE REGION. && .NEAR TERM /THROUGH MONDAY/... LOW-LEVEL STRATOCU DECK REMAINS EXPANSIVE...BUT STRONG BOUNDARY LAYER FLOW HAS MIXED DRIER AIR IN AND IS WORKING TO CREATE BREAKS. WEST OF THE FORECAST AREA...A SHORTWAVE RIDGE HAS LEAD TO CLEARING AND WILL GRADUALLY ERODE THE WESTERN EDGE OF OUR CLOUD DECK AS IT MOVES IN THROUGH LATE EVENING. TEMPERATURES HAVE BEEN HELD IN CHECK...BUT THE BREAKS IN THE CLOUDS HAVE ALLOWED TEMPERATURES TO JUMP UP A FEW DEGREES LOCALLY. CLOUDS SHOULD REMAIN ACROSS THE FAR NORTHERN PORTIONS OF THE FORECAST AREA TONIGHT...BUT WITH THE MOISTURE QUICKLY ERODING...RAIN SHOWERS SHOULD QUICKLY CEASE. MONDAY LOOKS TO BE FAIRLY DRY WITH THE WEAK RIDGE AT LEAST TEMPORARILY IN CONTROL. FLOW WILL BACK TO SOUTHERLY AS THE AXIS OF THE RIDGE PASSES BY MIDDAY. A STRONG WARMUP IS EXPECTED...BUT TEMPERATURES SHOULD HOLD AT OR JUST BELOW THE AVERAGE VALUES. AS QUICKLY AS THE RIDGE MOVES IN...IT MOVES OUT. MONDAY MORNING...ANOTHER LOW WILL DROP OUT OF THE NORTHERN PLAINS DIVING INTO THE BASE OF THE UPPER TROUGH NEAR THE SOUTHERN END OF LAKE MICHIGAN. ROUNDING THE BASE OF THE TROUGH MIDDAY MONDAY...THE LOW-LEVEL WIND FIELDS STRENGTHEN AND THE PROGRESSION OF THE LOW SLOWS DOWN. THIS TREND KEEPS POPS OUT OF THE WESTERN FRINGES OF THE FORECAST UNTIL THE WARM FRONT APPROACHES LATE MONDAY EVENING. LIMITED THUNDER POTENTIAL WITH THE APPROACHING LOW AS CAPE VALUES THROUGH EASTERN OHIO ARE MODEST AT BEST. TAX && .SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/...
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MODELS ARE STILL IN GOOD AGREEMENT LIFTING A WARM FRONT ACROSS THE CWA MONDAY NIGHT. HAVE A CROSSING BAND OF LIKELY POPS WITH A BRIEF SHOT OF DEEPER MOISTURE AND 305-310K ISENTROPIC LIFT. MAINTAINING A SLIGHT CHANCE OF THUNDER OVERNIGHT WITH POTENTIAL ELEVATED CONVECTION...NAM/GFS EVEN SHOW SURFACE-BASED CAPE SNEAKING INTO THE SOUTHERN COUNTIES PRIOR TO 12Z TUESDAY. SURFACE LOW PASSES JUST TO THE NORTHWEST ON TUESDAY. A FEW SHRA/TSRA WILL LINGER THROUGH THE MORNING...AND INSTABILITY AND LOW LEVEL LAPSE RATES ARE SUFFICIENT TO INCREASE COVERAGE DURING THE AFTERNOON. WHILE SOME MODEST SHEAR WILL BE PRESENT...MIDLEVEL FLOW LOOKS A BIT TOO WEAK TO SUPPORT A WIDESPREAD SEVERE THREAT. MARGINAL RISK ISSUED BY SPC LOOKS APPROPRIATE. YET ANOTHER MIDLEVEL WAVE WILL DIG ACROSS THE OHIO VALLEY LATER ON TUESDAY AND ROTATE ACROSS TUESDAY NIGHT. DISTURBANCE WILL BE SUFFICIENT TO KEEP SOME SCATTERED SHRA THROUGH THE NIGHT...BUT KEPT POPS AND THUNDER COVERAGE A BIT LOWER COMPARED TO MONDAY NIGHT AS ISENTROPIC LIFT IS WEAKER TO NONEXISTANT. WEDNESDAY LOOKS FAIRLY SIMILAR TO TUESDAY...WITH A DIURNAL INCREASE IN COVERAGE. MORE SPEED THAN VERTICAL SHEAR DURING THE AFTERNOON...BUT CANNOT RULE OUT AN ISOLATED STRONG STORM ONCE AGAIN. TEMPERATURES WILL BE NEAR TO JUST A TOUCH BELOW NORMAL THROUGH THE PERIOD. NO MAJOR CHANGES TO FORECAST THERE.
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&& .LONG TERM /WEDNESDAY NIGHT THROUGH SATURDAY/... EXTENDED FORECAST CONTINUES TO SHOW AN UNSETTLED PATTERN. WITH A FRONT REMAINING IN THE VICINITY OF THE FORECAST AREA...WILL CONTINUE THE CHANCE OF SHOWERS THROUGH MOST OF THE PERIOD. ALTHOUGH THE ENTIRE PERIOD WILL NOT BE A WASHOUT...STILL TOO MUCH UNCERTAINTY TO NAIL DOWN DRY PERIODS THIS FAR OUT. TEMPERATURES WILL REMAIN SLIGHTLY BELOW NORMAL. && .AVIATION /19Z SUNDAY THROUGH FRIDAY/... EXPANSIVE STRATOCU DECK LIFTING AND SHOWING SOME SIGNS OF DECAY AS STRONG BOUNDARY LAYER FLOW MIXES IN DRIER AIR AND A RIDGE PUSHES IN FROM THE WEST. STILL...MVFR AND SPOTTY IFR CONDTIONS ARE POSSIBLE THROUGH THE LATE EVENING AS THE UPPER-LEVEL LOW PULLS AWAY. LOW- LEVEL MOISTURE WILL LINGER TONIGHT ACROSS THE NORTHERN TERMINALS...WHERE RE-DEVELOPMENT OF LOW STRATUS IS EXPECTED. ELSEWHERE...CLOUDS BEGIN TO SCATTER OUT WITH SOME CLEARING GOING INTO THE OVERNIGHT HOURS. GUIDANCE SHOWING LIGHT MVFR FOG DEVELOPMENT FOR MOST TERMINALS...AND THIS SEEMS PRUDENT GIVEN THAT DEWPOINTS ARE NOT EXPECTED TO FALL OFF THIS EVENING. GRADUAL IMPROVEMENT TO VFR FOR ALL LOCATIONS MONDAY AS THE RIDGE TAKES CONTROL WITH DRIER WEATHER. TAX .OUTLOOK.../MONDAY THROUGH THURSDAY/... ANOTHER SYSTEM DIVING OUT OF THE UPPER MIDWEST MONDAY NIGHT COULD BRING ADDITIONAL RESTRICTIONS. AN UNSETTLED PATTERN WILL KEEP AT LEAST A CHANCE FOR RESTRICTIONS IN SCATTERED SHOWERS. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$

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