155
FXUS61 KPBZ 191937
AFDPBZ
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE PITTSBURGH PA
337 PM EDT FRI JUL 19 2019
SYNOPSIS
HOT, HUMID CONDITIONS WILL CONTINUE THROUGH THE WEEKEND WITH
AFTERNOON/EVENING RAIN CHANCES. A COLD FRONT ON MONDAY WILL THEN
BRING COOLER, DRIER WEATHER FOR MUCH OF NEXT WEEK.
NEAR TERM /UNTIL 6 AM SATURDAY MORNING/
PERSISTENT CLOUD COVER ACROSS MUCH OF THE AREA LED TO TEMPERATURES
SLIGHTLY COOLER THAN FORECAST THROUGH MUCH OF THE MORNING AND EARLY
AFTERNOON HOURS. MODEL AND AMDAR SOUNDINGS SHOWED QUITE AN INVERSION
ABOVE THE CLOUD DECK, WHICH KEPT THE DECK FROM MIXING OUT AS
INITIALLY EXPECTED. HOWEVER, LATEST GOES16 VISIBLE DATA SHOWS THE
CLOUD DECK FINALLY DIMINISHING. TEMPERATURES ARE STILL EXPECTED TO
CLIMB TO AROUND 90 DEGREES. GIVEN VERY MOIST AIRMASS / DEWS IN THE
MID 70S, HEAT INDICES WILL STILL CLIMB UP TO NEAR OR IN EXCESS OF
100F FOR MOST LOCALES OUTSIDE OF THE HIGHER ELEVATIONS.
CONVECTIVE INITIATION HAS BEGUN IN THE VICINITY OF ERIE AND PLACES
EASTWARD. ADDITIONALLY CONVECTION HAS INITIATED IN SE MICHIGAN IN
CLOSE PROXIMITY TO A MCV MOVING SOUTHEASTWARD TOWARDS LAKE ERIE.
CONVECTIVE ALLOWING MODELS (CAMS) ARE IN AGREEMENT THAT ADDITIONAL
CONVECTION WILL INITIATE IN THE I-90/I-80 CORRIDOR AFTER THE MCV OR
CURRENT CONVECTIVE CLUSTER CROSSES LAKE ERIE AND TO NEAR THE PBZ CWA
IN AN AREA OF >3000 J/KG MLCAPE AND STEEP LOW LEVEL LAPSE RATES.
DESPITE MINIMAL DEEP LAYER SHEAR (AND EVEN LESS IN AREAS SOUTH), THE
STRONGEST CELLS OR CLUSTERS MAY PRODUCE DAMAGING WIND GUSTS.
ANY CONVECTION WILL GRADUALLY DISSIPATE AFTER SUNSET WITH THE LOSS
OF HEATING. TEMPERATURES WILL REMAIN RATHER WARM OVERNIGHT WITH LOWS
ONLY EXPECTED TO GET INTO THE MID 70S.
SHORT TERM /6 AM SATURDAY MORNING THROUGH SATURDAY NIGHT/
A SIMILAR SITUATION IS EXPECTED SATURDAY. MORNING CLOUD COVER IS
POSSIBLE ONCE AGAIN AS MODEL FORECAST SOUNDINGS SHOW A SOMEWHAT DEEP
SATURATED/CLOUD LAYER BELOW THE EML. TEMPERATURES WILL AGAIN CLIMB
INTO THE UPPER 80S AND 90S ACROSS MOST OF THE FORECAST AREA. COMBINED
WITH DEWPOINTS IN THE MID 70S, HEAT INDICES WILL APPROACH OR EXCEED
100 FOR MOST LOCALES.
SCATTERED CONVECTION IS POSSIBLE SATURDAY AFTERNOON AND THE EVENING
WITH CONVECTIVE ACTIVITY DROPPING SOUTHWARD FROM LAKE ERIE.
ADDITIONALLY, ANY CONVECTIVELY-INDUCED MCVS FROM FRIDAY'S MIDWEST
CONVECTION MAY PROVIDE A FOCUS FOR CONVECTION ON SATURDAY.
LONG TERM /SUNDAY THROUGH FRIDAY/
RELIEF TO THIS SHORT-LIVED HEAT WAVE IS IN SIGHT AS GLOBAL MODELS
ARE IN AGREEMENT WITH THE BREAKDOWN OF THE CENTRAL/EASTERN CONUS
RIDGE AND THE ESTABLISHMENT OF A CLASSIC AMPLIFIED WESTERN CONUS
RIDGE WITH STRONG TROUGHING ACROSS THE EAST.
A COLD FRONT IS EXPECTED TO DROP DOWN AND STALL SOMEWHERE IN THE
VICINITY OF THE I-90 CORRIDOR ON SUNDAY MORNING AS CYCLOGENESIS
OCCURS UPSTREAM OVER THE PLAINS. WHILE THE QUASI-STATIONARY FRONT
SHOULD ACT AS A FOCUS FOR CONVECTION ON SUNDAY, SCATTERED CONVECTION
ACROSS THE CWA IS LIKELY WITH DIURNAL DESTABILIZATION.
COVERAGE IN SHOWERS/STORMS WILL PICK UP OVERNIGHT SUNDAY THROUGH
MONDAY MORNING AS THE AFOREMENTIONED TROUGH DEEPENS ACROSS THE GREAT
LAKES AND THE REGION SITS UNDER JET LEVEL RIGHT-ENTRANCE DIVERGENCE.
THE COLD FRONT WILL THEN PUSH THE REGION THROUGH THE DAY MONDAY AS
THE TROUGH AXIS AND LOW/MID-LEVEL LOW EXITS OFF TO THE NORTHEAST.
STRONG COLD AIR ADVECTION BEHIND THE COLD FRONT WILL MAKE FOR
SEASONAL OR EVEN SLIGHTLY BELOW SEASONAL TEMPERATURES FOR THE AREA
THROUGH MUCH OF NEXT WEEK. HIGHS WILL BE IN THE MID 70S TO LOW 80S
WITH LOWS IN THE MID 50S TO LOW 60S.
AVIATION /19Z FRIDAY THROUGH WEDNESDAY/
MEDIUM CONFIDENCE FORECAST GIVEN NOT SURE EXACT TIMING THE STRATOCU
WILL BURN OFF AND WHEN IT WILL RE-DEVELOP DURING THE PREDAWN HOURS.
MVFR STRATOCU HANGING ON TOUGH AND GIVEN RECENT TAMDAR SOUNDING A
PRETTY STOUT STABLE LAYER OF MOISTURE IN THE LOWEST 2KFT TO OVERCOME.
DID NOT LIFT TAFS TO HIGH END MVFR / LOW END VFR UNTIL 20Z, WHICH
MAY NOT HAPPEN. IF THE CLOUDS LIFT LOOK FOR VFR WEATHER UNTIL MORNING
STRATOCU DEVELOPS ONCE AGAIN BETWEEN 10Z-12Z. NO FOG IS FORECAST
TONIGHT GIVEN HOW WARM IT WILL BE.
THUNDERSTORM COMPLEX ACROSS THE GREAT LAKES COULD AFFECT NORTHERN
TAFS OF FKL AND DUJ AS EARLY AS 22-23Z THEN QUICKLY WEAKENS AFTER
SUNSET. AS A RESULT, CARRIED VCTS FOR THE TWO AFOREMENTIONED
TERMINALS AND KEPT THE REMAINING AIRPORTS PRECIP FREE.
WIND WILL BE FROM THE SOUTHWEST THE DURATION OF THE FORECAST. CAN NOT
RULE OUT AN OCCASIONAL GUST ABOVE 20KNOTS THIS AFTERNOON, BUT FOR
THE MOST PART LEFT OUT GUSTS IN THE FORECAST.
OUTLOOK
THE NEXT CHANCE FOR WIDESPREAD RESTRICTIONS WILL BE SUNDAY NIGHT INTO
MONDAY WITH THE PASSAGE OF A COLD FRONT.
PBZ WATCHES/WARNINGS/ADVISORIES
MD...NONE.
OH...EXCESSIVE HEAT WARNING UNTIL 8 PM EDT SATURDAY FOR OHZ039>041-
048>050-057>059-068-069.
PA...HEAT ADVISORY UNTIL 8 PM EDT SATURDAY FOR PAZ007>009-013>016-
020>023-029-031-073>076.
WV...EXCESSIVE HEAT WARNING UNTIL 8 PM EDT SATURDAY FOR WVZ001>004-012.
HEAT ADVISORY UNTIL 8 PM EDT SATURDAY FOR WVZ021-509>511.
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