211 FXUS61 KCTP 281138 AFDCTP AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE STATE COLLEGE PA 738 AM EDT FRI MAR 28 2014 .SYNOPSIS... LOW PRESSURE WELL TO OUR NORTH WILL DRAG A COLD FRONT ACROSS THE REGION LATER TODAY WITH RAIN SHOWERS FALLING FOR MUCH OF THE DAY. A SECOND WAVE OF LOW PRESSURE WILL THEN MOVE FROM THE TENNESSEE VALLEY INTO THE DELMARVA REGION BY SATURDAY NIGHT. THIS SYSTEM WILL BRING ADDITIONAL MODERATE TO HEAVY RAIN TO THE AREA...WITH MORE THAN AN INCH LIKELY TO FALL IN THE EAST. SOME SNOW IS POSSIBLE...ESPECIALLY ON THE HIGHER ELEVATIONS...AT THE END OF THE RAIN SUNDAY. MILDER TEMPERATURES BUT CONTINUED UNSETTLED CONDITIONS ARE EXPECTED FOR NEXT WEEK. && .NEAR TERM /UNTIL 11 AM THIS MORNING/... PRE-FRONTAL TROUGH IS SLIDING THROUGH NOW. ADDITIONAL WEAK FORCING AND LEFT OVERS FROM CONVECTION TO THE WEST WILL ALSO MOVE INTO THE AREA BEFORE TOO LONG. THE COLD FRONT IS WELL TO THE WEST WITH THE SFC LOW NEAR CHICAGO. LOW PROGGED TO MOVE VERY QUICKLY TO A POSITION OVER LK HURON BY 12Z...AND TO THE ONT/QUE BORDER WELL NORTH OF LK ONTARIO BY 18Z. THE COLD FRONT WILL LAG AND NOT GET INTO THE AREA UNTIL THE AFTERNOON. BY THIS TIME...MOST OF THE MOISTURE AND RAINFALL IS OFF TO THE EAST OF THE CWA. WINDS WILL GRADUALLY MIX DOWN INTO THE LOWER ELEVATIONS THIS MORNING...BUT BEFORE IT DOES THERE IS STILL A SLIGHT THREAT OF FREEZING RAIN IN THE COLDER VALLEYS. THEREFORE...HAVE KEPT A CHC/S CHC MENTION IN THE NE AND POCONOS FOR EARLY THIS MORNING. THE MIXING WILL THEN HELP TEMPS RISE ABOVE FREEZING WHERE IT IS NOT ALREADY. && .SHORT TERM /11 AM THIS MORNING THROUGH 6 PM SATURDAY/... THE COLD FRONT SHOULD BLAST THROUGH THIS AFTERNOON AND EARLY THIS EVENING WITH MUCH LIGHTER/SCT PRECIP THAN THE PRECIP IN THE FIRST HALF OF THE DAY. TOTALS FOR THE DAY MAY REACH JUST OVER A HALF OF AN INCH IN MANY PLACES. THIS SHOULD BE EASILY HANDLE-ABLE IN TERMS OF HYDRO RESPONSE ON THE WATERWAYS TODAY. BUT THIS WILL WETTEN THE GROUND AND SEEDS WILL BE PLANTED OF POSSIBLE MINOR FLOODING LATE SAT INTO SUNDAY. THE RESON WILL BE THE DEVELOPMENT OF A SFC LOW WHICH WILL PASS THROUGH THE MID-ATLANTIC/DELMARVA ON SATURDAY IN RESPONSE TO A STRONG UPPER TROUGH DIGGING AS IT PRESSES THROUGH THE OHIO/TN VALLEYS. GOOD MOISTURE FETCH FROM THE GOMEX WILL MEET IT/S TERMINUS OVER THE LOCAL AREA. THE FAST FORWARD SPEED OF MOVEMENT OF THE SYSTEM MAY BE VERY GOOD NEWS...AS ABNORMALLY HIGH PWATS ABOVE AN INCH WILL EXIST. QPF IS PEGGED TO BE IN THE 0.75-1.5 INCH RANGE BY ALL OPRL MDLS AND THE SREF MEANS AND MEDIANS. THE HEAVIER END OF THE NUMBERS ARE RIGHT NOW SLATED TO BE TO THE EAST OF THE NORTHERN/WESTERN MOUNTAINS. BUT THEY WILL HAVE THEIR OWN TRICK IN THE FORECAST. THE TEMPERATURES DROP AS THE RAIN BEGINS AND THROUGH THE DAY/EVENING - ESPECIALLY ON THE HIGHER ELEVATIONS. THIS WILL PROBABLY LEAD TO A CHANGEOVER TO SNOW FOR THE MOUNTAINS...THE TIMING OF WHICH WILL DICTATE THE AMOUNT OF SNOW WHICH MAY FALL. FOR NOW...THE 1-2 INCHES IN THE GRIDS ALREADY IS REASONABLE...AND WILL LEAVE ALONE. TEMPS WILL BE KEPT DOWN FROM MOS GUID ON SAT. && .LONG TERM /SATURDAY NIGHT THROUGH THURSDAY/... DID NOT CHANGE A LOT. DID UP POPS FOR LATER SATURDAY INTO SATURDAY NIGHT. SOME POTENTIAL FOR SOME SNOW ACROSS THE HIGHER TERRAIN AS THE WAVE ON THE FRONT PULLS OUT LATER IN THE WEEKEND. BEST DAY WILL BE MONDAY. CHC OF RAIN SHOWERS ON TUE WITH COLD FRONT. NOT REAL COLD ON WED. CHC OF MORE RAIN SHOWERS ON THU WITH WARM FRONT. STILL A LOT OF MODEL SPREAD FOR WEEKEND. EARLIER DISCUSSION BELOW. SHORTWAVE TROUGH AND SFC LOW OVER THE NRN GRT LKS REGION AT 12Z FRI MOVG NEWD INTO SRN QUEBEC BY 00Z SAT. THE TRAILING COLD FRONT WILL BE THE FOCUS FOR A BAND OF SHOWERS EXTENDING SWD ALONG THE APPLCHNS EARLY FRI BEFORE SHIFTING EWD AND STALLING OUT INVOF THE MID-ATLC PIEDMONT AND COASTAL PLAIN. H85 MSTR FLUX/AXIS OF ABV NORMAL PWATS PRESENT ALONG THE COLD FRONT ASSOCIATED WITH STG LLVL WAA VIA 50+KT WSWLY LLJ COUPLED WITH MINIMAL MODEL SPREAD IN THE PCPN TIMING WILL SUPPORT ABV AVG CONFIDENCE IN FCST CATG POPS WITH LGT-MOD QPF AMTS GENERALLY IN THE 0.25 TO 0.50 RANGE. THE NEXT H5 SHORTWAVE OF PACIFIC ORIGIN OVER THE PLAINS FRI NGT IS FCST TO AMPLIFY AS IT PROGRESSES EWD THRU THE OH VLY/MID-SOUTH DURING THE DAY SATURDAY AND ARRIVES IN THE MID-ATLC STATES BY 12Z SUN. AN ATTENDANT SFC LOW SHOULD TRACK ENEWD FROM ERN KY/TN THRU NC/WV/VA TO A POSITION OFF THE MID-ATLC/SRN NEW ENGLAND COAST BY SUNDAY MORNING. THE MODEL SPREAD WITH THIS SYSTEM IS MUCH GREATER THAN THE SYSTEM FOR FRIDAY. && .AVIATION /12Z FRIDAY THROUGH TUESDAY/... REGIONAL RADAR AT 11Z SHOWS SHRA HAVE SPREAD INTO CENTRAL PA IN ADVANCE OF LOW PRES TRACKING THRU THE GRT LKS. HOWEVER...DRY AIR AT LOW LVLS IS RESULTING IN MAINLY VFR CONDS...EVEN WHERE RAIN IS FALLING. EXPECT DETERIORATING FLYING CONDS LATER THIS MORNING...AS A SURGE OF MOISTURE AHEAD OF APPROACHING FRONTAL BOUNDARY BRINGS ADDITIONAL SHRA AND LOWERING CIGS. BASED ON UPSTREAM OBS AND NEAR TERM MDL DATA...WIDESPREAD MVFR CIGS APPEAR LIKELY LATER THIS MORNING. OTHER POINT OF CONCERN THIS MORNING WILL BE LLWS. MDL DATA INDICATES THE STRONGEST WINDS ALOFT WILL CLIP NW PA...SO KBFD IS MOST LIKELY TO REACH LLWS CRITERIA THIS MORNING...WHILE LLWS LOOKS MARGINAL FURTHER SE. SOME MODEST IMPROVEMENT IS EXPECTED THIS AFTN...AS SFC WARM FRONT LIFTS THRU THE AREA...BRINGING RISING CIGS AND CAUSING SHRA TO TAPER OFF. A TRAILING COLD FRONT WILL PASS THROUGH THE AREA THIS EVENING...ACCOMPANIED BY A WIND SHIFT FROM SW TO NW AND FOLLOWED BY IMPROVING FLYING CONDS AFTER DARK...AS DRIER AIR WORKS IN. OUTLOOK... SAT...WIDESPREAD PM RAIN/LOW CIGS POSSIBLE. SUN...WINDY. AM RAIN/LOWS CIGS POSSIBLE. MON-TUE...NO SIG WX EXPECTED. && .CTP WATCHES/WARNINGS/ADVISORIES... NONE. && $$ SYNOPSIS...DANGELO NEAR TERM...DANGELO SHORT TERM...DANGELO LONG TERM...MARTIN/STEINBUGL AVIATION...FITZGERALD