Area Forecast Discussion
Issued by NWS State College, PA

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000 FXUS61 KCTP 291933 AFDCTP AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE STATE COLLEGE PA 333 PM EDT TUE JUL 29 2014 .SYNOPSIS... BELOW NORMAL TEMPERATURES WILL CONTINUE TO GRIP THE REGION INTO EARLY AUGUST BENEATH A BROAD AND ANOMALOUS UPPER LEVEL TROUGH CARVED OUT OVER THE EASTERN U.S. THE OPPORTUNITY FOR APPRECIABLE RAINFALL SHOULD PEAK DURING THE WEEKEND BEFORE DRYING OUT INTO EARLY NEXT WEEK. && .NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/... DAYTIME HEATING COMBINED WITH UNSEASONABLY COLD CYCLONIC FLOW PATTERN ALOFT /MORE REMINISCENT OF THE TRANSITION SEASONS/..COMPLETE WITH SIGNIFICANT ANOMALIES IN BOTH H85/H7 TEMPERATURES AND 500MB HEIGHTS..CONTINUES TO PROMOTE INCR CVRG OF INSTABILITY CU/SC PER LATEST VISIBLE STLT LOOP. 16Z REGIONAL RADAR MOSAIC IS VOID OF SHOWER ACTIVITY...WITH LITTLE TO NO CHANGE EXPECTED THIS AFTN/EVE BASED ON CONSENSUS OF NEAR TERM HIRES MODEL GUIDANCE. HOWEVER WILL KEEP SCHC POPS ACRS THE N/W ZONES NEAR THE LEADING EDGE OF COLDEST AIR ALOFT /-15C AT 500MB/ AND THUS STEEPER MID-LVL LAPSE RATES OF 6C/KM. AFTERNOON HIGHS PROGGED IN THE MID 60S TO MID 70S WILL AVG 10-15F BELOW LATE JULY NORMALS...A FAR CRY FROM THE USUAL DOG DAYS OF SUMMER. EXPECT SOME DECREASE IN CLOUD COVER INTO TONIGHT ESPECIALLY OVER ERN SXNS. DESPITE P-M CLOUDY SKIES...IT SHOULD BE ANOTHER RELATIVELY COOL NIGHT WITH LOWS LKLY APPROACHING /WITHIN ~3 DEGREES/ DAILY CLIMATE RECORDS IN SOME LOCATIONS WITH READINGS GENERALLY IN THE LOW-MID 50S...SIMILAR TO 7/29 MINS. DIURNAL COOLING/STABILIZATION SHOULD RESULT IN A MAINLY DRY AND TRANQUIL OVERNIGHT BUT SUPPOSE ANY WK EMBEDDED SHORTWAVE IN THE CYC FLOW COULD TOUCH OFF A STRAY SHOWER...WITH THE BEST CHC OVER THE FAR N/W ZONES. && .SHORT TERM /6 AM WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT/... POTENT SHORTWAVE ROTATING S OF NEARLY STNRY UPPER LOW OVER JAMES BAY INTO THE ERN GRT LKS REGION WILL TEAM WITH DAYTIME HEATING TO LEAD TO WEAK INSTABILITY WITH ABNORMALLY COOL CYC FLOW ALOFT. STEEP MID-LVL LAPSE RATES WILL SPREAD INTO CENTRAL PA DURING THE LATE MORNING AND AFTN BENEATH POOL OF -15 TO -16C AIR AT 500MB. EXPECT SCT CONVECTION TO DEVELOP WITH SOME STORMS CONTAINING SMALL HAIL AND HAVE CONTINUED MENTION IN NDFD FCST AND ZONE TEXT. SUPPOSE A FEW STRONGER CORES COULD HAVE HAIL APPROACHING SVR LIMITS /1 INCH DIAMETER/ BEFORE GRADUALLY DIMINISHING INTO WED NGT WITH THE LOSS OF HEATING. SPC D2 STILL HIGHLIGHTS THE NW MTNS WITH A SEE TEXT. D2 MAX/MINS SHOULD WARM A FEW DEGREES BUT REMAIN BELOW LATE JULY CLIMATE NORMALS. && .LONG TERM /THURSDAY THROUGH TUESDAY/... A DEEP UPPER LEVEL TROUGH WILL BE PRESENT ACROSS SOUTHEASTERN CANADA EARLY IN THE LONG TERM PERIOD...BUT WILL RELOAD WITH A SIGNIFICANT CHUNK ENERGY DIGGING INTO IT/S SW FLANK ACROSS THE MID MISS AND OHIO RIVER VALLEYS LATE THIS WEEK AND OVER THE UPCOMING WEEKEND /AS THE CANADIAN PORTION SHEARS OUT TO THE NE/. THIS POTENT SHORTWAVE TROUGH /AND AN ASSOCIATED WELL-DEFINED RIGHT ENTRANCE REGION OF A 90-95 KT 300 HPA JET/ WILL LIFT NORTHEAST ACROSS THE MID ATLANTIC REGION FRIDAY THROUGH SUNDAY BEFORE SHIFTING TO THE SOUTHERN NEW ENGLAND COAST BY THE START OF NEXT WEEK. A SLOW MOVING /AND LIKELY STRENGTHENING/ BAROCLINIC ZONE... AND ONE OR MORE WAVES OF WEAK LOW PRESSURE MVG NE ALONG IT WILL BE LOCATED ACROSS CENTRAL OR ERN PENN DURING THIS 2-3 DAY PERIOD. WHAT THIS MEANS FOR OUR SENSIBLE WEATHER IS FOR A MAINLY DRY THURSDAY INTO FRIDAY WITH SLIGHTLY BELOW NORMAL TEMPS. A FEW WEAK IMPULSES ALOFT WILL RIDE EAST IN THE TEMPORARY ZONAL FLOW AND BRING THE LOW PROBABILITY OF AN AFTERNOON SHOWER OR BRIEF... LOW-TOPPED TSRA BOTH DAYS. PERIODS OF UNSETTLED WEATHER /SHOWERS AND TSTMS/ WILL OCCUR LATER FRIDAY...SATURDAY AND SUNDAY. THE STRENGTH OF THE LARGE SCALE FORCING AND INCREASINGLY ANOMALOUSLY HIGH PWAT AIR BENEATH THE NORTHWARD MIGRATING JET AND ITS THERMALLY DIRECT BRANCH WILL BRING THE POTENTIAL FOR SOME LOCALLY HEAVY/TRAINING SHOWERS AND TSRA... ESP ACROSS THE EASTERN HALF OF THE STATE/. MODEL DETAILS DIFFER SLIGHTLY WITH RESPECT TO THE TIMING AND LOCATION OF THE STRONGEST MESO/LARGER SCALE FORCING...BUT ALL GUIDANCE AGREES ON THE BASIC EVOLUTION AND NE MOVEMENT OF THIS TROUGH /AND AXIS OF HIGH...40-50MM PWAT AIR/ RIDING NWD UP ALONG THE MID ATLANTIC PIEDMONT...AND SPREADING ACROSS THE EASTERN HALF OF OUR CWA. AS A RESULT OF THESE TIMING/LOCATION DIFFERENCES...POPS WERE CAPPED OFF IN THE HIGH CHC CATEGORY...BUT AS THE FINER DETAILS UNFOLD WITH HIGHER RES MODEL GUIDANCE OVER THE NEXT FEW DAYS...POPS WILL UNDOUBTEDLY TREND HIGHER FOR SEVERAL PERIODS BETWEEN LATE FRIDAY AND SUNDAY. GRADUAL IMPROVEMENT /WITH NEAR NORMAL TEMPS/ IS EXPECTED FOR EARLY NEXT WEEK. && .AVIATION /19Z TUESDAY THROUGH SUNDAY/... LOW VFR CIGS WILL PERSIST INTO THE EVE WITH SOME DEC IN CLOUDS AFTER DARK. AN ISOLD -SHRA IS PSBL MAINLY OVR THE NW 1/3 OF THE AIRSPACE ALTHOUGH CVRG IS SPARSE ENOUGH NOT TO MENTION IN TAFS. MUCH LIKE THIS MORNING...SUPPOSE CIGS MAY TRY TO LOWER INTO MVFR RANGE DURING THE PREDAWN AND EARLY MORNING HOURS WED...BUT FOR NOW WILL MAINTAIN VFR. APPROACH OF UPPER LEVEL DISTURBANCE FROM THE ERN GRT LKS ALONG WITH WEAK INSTABILITY SHOULD PROMOTE SCT SHRA AND LOW-TOPPED TSTM DEVELOPMENT FROM LATE WED MORNING INTO THE AFTN..WITH SOME OF THE STRONGEST STORMS CONTAINING SMALL TO MARGINALLY SVR HAIL. OUTLOOK... WED...SCT PM TSRA IMPACTS POSSIBLE. THU...AM FOG POSSIBLE NW MTNS. FRI-SAT...SCT PM TSRA IMPACTS POSSIBLE. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...STEINBUGL NEAR TERM...STEINBUGL SHORT TERM...STEINBUGL LONG TERM...LAMBERT AVIATION...STEINBUGL

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