Area Forecast Discussion
Issued by NWS State College, PA

Current Version | Previous Version | Graphics & Text | Print | Product List | Glossary Off
Versions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50
-- Remove Highlighting --
-- Discussion containing changed information from previous version are highlighted. --
000 FXUS61 KCTP 191331 AFDCTP AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE STATE COLLEGE PA 931 AM EDT SUN APR 19 2015 .SYNOPSIS... A WARM FRONT AND UPPER LEVEL DISTURBANCE APPROACHING FROM THE TENNESSEE VALLEY WILL BRING A SOAKING RAIN TO THE REGION TONIGHT AND EARLY MONDAY. ADDITIONAL SHOWERS AND SCATTERED THUNDERSTORMS WILL ACCOMPANY A COLD FRONT AS IT PUSHES EAST ACROSS THE STATE MONDAY AFTERNOON AND EVENING. A LARGE UPPER LEVEL LOW WILL SET UP OVER ONTARIO AND QUEBEC FOR THE MIDDLE AND LATTER PART OF THE WEEK...USHERING IN UNSEASONABLY COOL AIR WHICH WILL LAST INTO THE WEEKEND OR LONGER. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... EXTENSIVE CIRROSTRATUS WILL LEAD TO PERIODS OF DIMMED SUNSHINE TODAY. A RIDGE OF HIGH PRESSURE AT THE SURFACE AND ALOFT WILL SLIDE OFF THE EAST COAST AND CREATE AN INCREASING SOUTHEAST WIND THIS AFTERNOON AND EVENING WITH CLOUDS LOWERING AND THICKENING UP FROM THE SOUTHWEST LATE TODAY. THE THICKENING CLOUDS AND UPSLOPE FLOW OF COOLER MARINE AIR WILL KEEP TEMPS ABOUT 10-15F LOWER THAN SATURDAY/S UNSEASONABLY WARM VALUES IN THE 70S TO LOWER 80S. LATEST MODEL TIMING INCLUDING THE NAM 06Z RUN SUGGESTS THE BULK OF THE REGION WILL BE DRY FOR MUCH OF THE DAY...EVEN BACKING OFF/BEING SLOWER WITH ONSET. FAR SOUTHWESTERN AREAS WILL LIKELY SEE SHOWERS BY/AROUND 4 OR 5 PM. CENTRAL LOCATIONS MAY SEE RAIN BY NIGHTFALL AS THE PRECIP SPREADS SLOWLY NORTHEAST. SEE FIRE WX SECTION FOR INFO AS WELL. && .SHORT TERM /6 PM THIS EVENING THROUGH MONDAY NIGHT/... LITTLE TO NO CHANGE WAS NECESSARY FROM THE PREVIOUS FEW FORECAST CYCLES FOR THIS SHORT TERM PERIOD. THE MAIN CHANGE WAS TO FURTHER REFINE THE TIMING AND TO SHOW A SLIGHTLY MORE-OBVIOUS 4-6HR BREAK BETWEEN THE OVERNIGHT/MORNING RAIN AND THE STORMS IN THE AFTERNOON/EVENING. MINS WILL BE HELD UP AS THE WINDS WILL BE BREEZY. USUALLY...CENTRAL PA DOES NOT GET STRONG WIND GUSTS DURING STABLE SERLY FLOW RAIN EVENTS. SO THOUGHTS OF A WIND ADVY WERE DISCOUNTED RATHER EARLY IN THE FORECAST PROCESS TONIGHT. HOWEVER...THE STRONG LOW AND MID LEVEL FLOW WILL BUMP THE PWATS INTO THE 1-1.5 INCH RANGE TONIGHT AND MONDAY. THUS...RAIN COULD BE HEAVY AT TIMES. WITH THE ADDITIONAL TSRA MON PM...THE QPF REACHES BETWEEN 0.75 AND 1.25 INCHES OVER A LARGE PORTION OF THE AREA. BUT THE STREAM FLOWS ARE REALLY LOW AND NO THUNDER TONIGHT SHOULD TRANSLATE INTO NO FLOOD WORRIES OTHER THAN SOME PONDING OF WATER ON ROADS AND A FEW SMALL CREEKS AT BANKFULL. THINGS ARE GROWING NICELY NOW IN THE SE AND EVEN LOCALLY IN HAPPY VALLEY WHICH SHOULD TAKE UP PLENTY OF WATER COMPARED TO JUST TWO WEEKS AGO. SPC HAS PLACED ALL OF THE AREA INTO MRGL RISK AND BROUGHT THE DAY2 SLGT RISK INTO SRN PA...RIGHTFULLY SO. THE BREAK AND ASSOCIATED BREAKS IN THE CLOUDS/WARM SECTOR ON MONDAY WILL LEAD TO GOOD HEATING AND THE FRONT/FORCING COMES THROUGH AT AN OPPORTUNE TIME TO GRAB THE MAX CAPES AND MIN STABILITY. CAPES MAY BE AROUND 1500J/KG AND LI/S DROP TO -3 TO -5. WIND PROFILES ARE MAINLY MULTI-CELLULAR - BUT WITH THE WARM FRONT LIKELY CUTTING THROUGH THE AREA AT THE TIME...WILL NEED TO KEEP AN EYE OUT FOR ROTATING STORMS - ESPECIALLY IF THEY OCCUR ON OR NEAR LLVL BOUNDARIES. && .LONG TERM /TUESDAY THROUGH SATURDAY/... BEHIND THE COLD FRONT MIDWEEK...THE UPPER LOW HANGS AROUND S CANADA/NEW ENGLAND FOR SEVERAL DAYS KEEPING FAIRLY BRISK W/NW FLOW ACROSS PA. THIS WILL BRING A STEADY STREAM OF COLDER AIR AS TEMPS SLOWLY SLIP A BIT LOWER EACH DAY WITH BELOW NORMAL READINGS FOR A SEVERAL DAY PERIOD LINGERING INTO NEXT WEEKEND. PROXIMITY OF UPPER LOW WILL ALSO KEEP MENTION OF SCT SHOWERS IN THE FORECAST... MAINLY DURING THE DAYTIME HOURS. WEDNESDAY MAY HOLD A FAST-MOVING SHORT-WAVE WHICH COULD PRODUCE WHITE PRECIP - BUT DURING THE MIDDLE OF THE DAY. && .AVIATION /13Z SUNDAY THROUGH THURSDAY/... VFR CONDITIONS WILL PREVAIL MUCH OF THE DAY...BUT RAPIDLY DETERIORATE FROM SOUTHWEST TO NORTHEAST TONIGHT. EXPECT RESTRICTIONS TO REACH THE FIRST CENTRAL PENNSYLVANIA AIRFIELDS AROUND 00Z MONDAY /KJST/. TIGHTENING GRADIENT LATER TODAY AND TONIGHT AHEAD OF AN APPROACHING COLD FRONT WILL PRODUCE GUSTY WINDS...AND LOW LEVEL WIND SHEAR CONDITIONS. THESE HAVE NOW BEEN ADDED TO ALL TAFS STARTING BETWEEN 00 AND 04Z. RAIN AND WIDESPREAD IFR TO LIFR TONIGHT INTO MONDAY...BEFORE THE PRECIPITATION BECOMES MORE SHOWERY WITH THE APPROACH OF THE FRONT. THIS COLD FRONT WILL ALSO INTRODUCE THE CHANCE OF THUNDERSTORMS MONDAY TO THE ENTIRE REGION. OUTLOOK... MON...WIDESPREAD RESTRICTIONS IN RAIN EARLY...SOME IMPROVEMENT IN THE AFTERNOON...BUT TSRA POSSIBLE. TUE- THU...UNSETTLED WITH NW FLOW EACH DAY...WITH AREAS OF RESTRICTED CIGS/VSBYS IN SHRA IN THE WESTERN AND NORTHERN MOUNTAINS...SPOTTY RESTRICTIONS IN MORE SCATTERED SHRA IN CENTRAL MOUNTAINS...AND MAINLY VFR IN THE EAST AND SOUTHEAST. && .FIRE WEATHER... WIND WILL BE LIGHT THIS MORNING BUT WILL VEER FROM NORTHEAST TO MORE SOUTHEASTERLY AND ALSO PICK UP THROUGH THE DAY. WIND GUSTS BY THE MIDDLE OF THE AFTERNOON WILL BE INTO THE 20S OVER THE WEST. GUSTS OF 15 TO 20 MPH ARE POSSIBLE IN THE NORTHEAST BY LATE AFTERNOON. THE RH/S WILL DIP TO 30 PCT FOR AN HOUR OR TWO IN THE LATE AFTERNOON IN THE NORTH AND NORTHEAST. BUT THE GUSTS OVER 20MPH WILL ONLY MATCH UP WITH THE LOW RH/S FOR AN HOUR OR TWO AT THE MOST AND ONLY IN A SMALL PORTION OF THE NORTHERN MOUNTAINS. WILL HOLD OFF ON A RED FLAG WARNING FOR THE TIME BEING. BUT IF THE WINDS PICKS UP SOONER IN THE DAY...WE WILL NEED TO REVISIT THE NEED FOR AN RFW. A SIGNIFICANT RAINFALL IS EXPECTED STARTING THIS EVENING AND LASTING UNTIL A COLD FRONT PUSHES THROUGH ON MONDAY AFTERNOON AND EVENING. COOLER TEMPERATURES FOR THE REST OF THE WEEK WILL LIKELY LEAD TO HIGHER RH/S AND KEEP FIRE WEATHER CONDITIONS BELOW CRITICAL. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...DANGELO/LAMBERT NEAR TERM...DANGELO/LAMBERT SHORT TERM...DANGELO LONG TERM...CERU/RXR AVIATION...JUNG FIRE WEATHER...

USA.gov is the U.S. government's official web portal to all federal, state and local government web resources and services.