Area Forecast Discussion
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000 FXUS61 KPBZ 141615 AFDPBZ AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE PITTSBURGH PA 1215 PM EDT MON APR 14 2014 .SYNOPSIS... A STRONG COLD FRONT WILL BRING SHOWERS AND STORMS TO THE AREA LATER TODAY AND OVERNIGHT. MUCH COLDER AIR TUESDAY WITH THE CHANCE FOR SNOW SHOWERS. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... A STRONG COLD FRONT HAS REACHED WESTERN OHIO EARLY THIS AFTERNOON. ONE WAVE TRACKING DOWN THE FRONT WITH THE FIRST IN A SERIES OF WEAK UPPER LEVEL JETLETS AND MID-LEVEL WAVES IS QUICKLY TRACKING NORTHEASTWARD DOWN THE FRONT. THE BULK OF THE QPF IN ASSOCIATION WITH THIS WAVE IS LIKELY TO FALL WEST AND NORTH OF THE AREA...WHILE THE WAVE ITSELF ACTUALLY HAS MANAGED TO SLOW THE FRONT A BIT THROUGH THE MORNING. HOWEVER...THE SHIELD OF SHOWERS SHOULD CONTINUE TO SLOWLY TRACK EASTWARD AND ENCOMPASS MUCH OF THE FORECAST AREA LATER THIS AFTERNOON. DUE TO ABUNDANT CLOUD COVER AND ONGOING RAIN IN THE AREAS WHERE MODEL SOLUTIONS SUGGEST INSTABILITY AND SHEAR SHOULD BE MAXIMIZED THIS AFTERNOON...IT SEEMS LARGE SCALE DESTABILIZATION IS UNLIKELY UNTIL YOU GET WEST OF OUR AREA AND CLOSER TO THE ACTUAL SURFACE FRONT. AS SUCH...THUNDERSTORM WORDING WAS ROLLED BACK A CATEGORY YET AGAIN...PARTICULARLY GIVEN THAT NONE HAS BEEN NOTED INT HE REGION...EVEN IN THE MORE UNSTABLE/LESS RAIN COOLED AREAS. FRIES && .SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY/... FRONT SLOWLY MOVES THROUGH THE AREA LATE TONIGHT/EARLY TUESDAY MORNING. THE CONVECTIVE THREAT WILL DECREASE TONIGHT AND WINDS WILL RELAX. MOST OF THE PRECIPITATION WILL MOVE THROUGH DURING FRONTAL PASSAGE. MUCH COLDER AIR WILL QUICKLY RUSH IN BEHIND THE FRONT...WHICH SHOULD BE COLD ENOUGH TO CHANGE POST FRONTAL RAIN SHOWERS TO SNOW SHOWERS. LOOKING WESTWARD...FRONT IS SEPARATING A WIDE RANGE OF TEMPS WITH READINGS EAST OF THE FRONT IN THE MID 60S TO TEMPERATURES BEHIND THE FRONT IN THE UPPER 30S TO MID 40S. LOW CONFIDENCE IN THE CURRENT AMOUNT OF QPF MODELS ARE CREATING BEHIND THE FRONT. AT THIS TIME...IT LOOKS AS IF THERE IS A PERIOD DIRECTLY BEHIND THE FRONT WHERE THE MODELS ARE OVER DOING THE AMOUNT OF LIFT. THIS SHORT PERIOD OF STRONG OMEGA IS LIKELY CAUSING AN OVER AMPLIFICATION OF QPF AMOUNTS TUESDAY MORNING. TEMPS WILL BE VERY TRICKY ON TUESDAY...LATEST MODEL SOUNDINGS ARE INITIALLY SHOWING A RAPID DROP OF SURFACE TEMPERATURES WITH FROPA...AS A SHALLOW LAYER OF LOW LEVEL COLD AIR SETTLES IN. THIS FEATURE SHOWS UP WELL WITH AN EXAMINATION OF LAYERED THICKNESSES. LOW LEVEL THICKNESS WILL BECOME COLD ENOUGH FIRST TO SUPPORT SNOW...HOWEVER THE COLD MID LEVEL THICKNESSES ARE LAGGING BEHIND BY ABOUT 3 HOURS. THIS SETUP WOULD LIKELY PRODUCE A MIX OF RAIN AND SNOW WHICH WOULD EVENTUALLY CHANGE TO ALL SNOW. THE OTHER QUESTION IS HOW FAR DO TEMPS DROP AND WILL THERE BE ANY RECOVERY DURING THE DAY WITH STRONG CAA ONGOING THROUGHOUT THE DAY. THE NEXT HEADACHE WILL ARRIVE LATE TUESDAY AFTERNOON THROUGH TUESDAY EVENING. VERY COLD AIR WILL CROSS THE GREAT LAKES AND STRONG WINDS ALOFT WILL BE OUT OF THE NORTHWEST. THE MAIN SHORTWAVE TROUGH SWINGS THROUGH DURING THIS TIME AND MODELS ARE HINTING AT A PERIOD OF LAKE EFFECT/ENHANCED SNOW SHOWERS. INVERSIONS TUESDAY EVENING ARE PLENTY DEEP ENOUGH TO SUPPORT LES. INVERSIONS QUICKLY DROP TUESDAY NIGHT AS WINDS ALOFT VEER TO THE NORTH AND A STRONG SURFACE HIGH WILL BUILD IN FROM THE WEST. THIS WILL BRING A QUICK END TO ANY SNOW SHOWERS THAT DEVELOP. COLD AIR WILL EVACUATE TOWARD THE NORTH WEDNESDAY...THIS WILL ALLOW FOR A QUICK DECREASE IN CLOUD COVER AND A MODERATION IN TEMPS. && .LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/... A RETURN TO SPRING FOR THE LONG TERM...WITH THE RISK FOR SHOWERS FRIDAY NIGHT/SAT. && .AVIATION /16Z MONDAY THROUGH FRIDAY/... PRIMARY AVIATION CONCERN OF THE MRNG WL BE LLVL WIND SHEAR AS LLVL JET STREAKS ACRS THE REGION. MIXING AFTER DAYBREAK WL THEN SPPRT SFC GUSTS OF 25 TO 35KT. OTHERWISE...VFR CAN BE EXPECTED INTO AFTN...BUT CONDITION DETERIORATION SHOULD BE ANTICIPATED THEREAFTER AS SHWRS DVLP WITH THE ADVN OF A CDFNT ACRS THE MIDWEST. WIDESPREAD RAIN AND RESTRICTIONS ARE FORECAST AS EVE FALLS. .OUTLOOK.../TUESDAY THROUGH FRIDAY/... RESTRICTIONS ARE EXPECTED UNTIL COLD HIGH PRES BLDS LTR ON TUESDAY. && .PBZ WATCHES/WARNINGS/ADVISORIES... MD...NONE. OH...NONE. PA...NONE. WV...NONE. && $$

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