Area Forecast Discussion
Issued by NWS Mt. Holly, NJ

Current Version | Previous Version | Text Only | Print | Product List | Glossary On
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 KPHI 231535 AFDPHI AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MOUNT HOLLY NJ 1135 AM EDT THU APR 23 2015 .SYNOPSIS... A WEAKER SECONDARY COLD FRONT WILL CROSS THE AREA TODAY. A HIGH PRESSURE SYSTEM WILL BRIEFLY BUILD OVER THE REGION FRIDAY INTO EARLY SATURDAY. LOW PRESSURE IS THEN FORECAST TO PASS BY TO OUR SOUTH FROM SATURDAY NIGHT INTO SUNDAY, TRACKING FROM AROUND THE TENNESSEE VALLEY TO OFF THE CAROLINA COAST. ANOTHER HIGH PRESSURE SYSTEM SHOULD BRIEFLY BUILD INTO THE AREA ON MONDAY AND TUESDAY. THEN A LOW PRESSURE SYSTEM PREDICTED TO FORM IN THE GULF OF MEXICO SHOULD REACH THE NORTH CAROLINA COASTAL WATERS ON WEDNESDAY. && .NEAR TERM /UNTIL 6 PM THIS EVENING/...
-- Changed Discussion --
AN AREA OF LOW PRESSURE WILL REMAIN NEARLY STATIONARY AND CONTINUE TO SPIN ACROSS SOUTHEASTERN CANADA TODAY. STRONG WESTERLY AND NORTHWESTERLY WINDS WILL CONTINUE THROUGH THE AFTERNOON AND INTO THE EARLY EVENING, WITH GUSTS AROUND 30 MPH POSSIBLE THROUGH THIS TIME. A WEAK COLD FRONT/SURFACE TROUGH IS EXPECTED TO SLIDE ACROSS THE AREA THIS AFTERNOON. AS THIS HAPPENS, LOW-MID LEVEL LAPSE RATES ARE FORECAST TO INCREASE AND THERE IS SOME MOISTURE FORECAST TO MOVE ACROSS THE AREA. THIS COULD LEAD TO SOME ISOLATED SHOWER ACTIVITY DEVELOPING TO OUR WEST AND MOVING INTO OUR AREA. BASED ON UPSTREAM OBS, THESE SHOWERS COULD BE A RAIN/SNOW MIX FOR MUCH OF SE PA AND CENTRAL AND NORTHERN NJ. FOR NOW, THE GREATEST POSSIBILITY IS FOR OUR NORTHWESTERN THIRD OF THE AREA. ITS POSSIBLE SOME SPRINKLES COULD MAKE IT DOWN INTO THE TIER OF COUNTIES DOWN, SO WE`VE INCLUDED A CHANCE OF SPRINKLES THERE.
-- End Changed Discussion --
&& .SHORT TERM /6 PM THIS EVENING THROUGH 6 AM FRIDAY/... ANY SHOWERS AND/OR SPRINKLES ARE EXPECTED TO DISSIPATE BY THIS EVENING AS DAYTIME INSTABILITY IS LOST AND THE SURFACE TROUGH MOVES EASTWARD. SKIES WILL LIKELY REMAIN PRETTY CLOUDY FOR MUCH OF THE NIGHT HOWEVER. WITH THE LOW REMAINING TO OUR NORTHEAST, THE PRESSURE GRADIENT WILL REMAIN ACROSS THE AREA, KEEPING A STEADY BREEZE FOR MUCH OF THE NIGHT. HOWEVER, WE STILL EXPECT COLD TEMPERATURES TONIGHT AS COLD AIR ADVECTION WILL CONTINUE THROUGH THE NIGHT. WE`VE ISSUED A FREEZE WARNING FOR AREAS WHERE WE ARE MOST CONFIDENT OF SUB- FREEZING TEMPERATURES OCCURRING OVERNIGHT, AND A FREEZE WATCH FOR THOSE AREAS WHERE WE ARE A LITTLE MORE UNCERTAIN. WITH THE BREEZE EXPECTED, IT MAY BE HARD TO DEVELOP MUCH FROST, SO THAT`S WHY WE HAVEN`T INCLUDED FRONT IS THE FORECAST OR ISSUED A FROST ADVISORY AT THIS TIME. && .LONG TERM /FRIDAY THROUGH WEDNESDAY/...
-- Changed Discussion --
THE LONG TERM BEGINS WITH CONTINUED FROST/FREEZE CONCERNS BEFORE SHIFTING FOCUS TO TWO DIFFERENT LOW PRESSURE SYSTEMS. FRIDAY NIGHT...THE FREEZE WATCH CONTINUES FOR MOST OF OUR PA AND NJ ZONES WHERE THE GROWING SEASON HAS STARTED. EXCEPTION IMMEDIATE COAST AND PHL AREA. LESS CONFIDENCE IN DELMARVA ALTHOUGH THE SFC HIGH PRESSURE SHOULD BE CLOSE ENOUGH TO DECOUPLE WINDS, RESULTING IN PLENTY OF RADIATIONAL COOLING. ANOTHER SIGNAL IS THE WAA PREDICTED ABOVE THE BOUNDARY LAYER. BECAUSE WINDS WILL BE LIGHTER, WE HAVE INCLUDED FROST IN THE GRIDS. SLIGHTLY UNDERCUT GUIDANCE TO ACCOUNT FOR RADIATIONAL COOLING WHICH ISN/T ALWAYS DEPICTED WELL BY MODELS. SATURDAY INTO SUNDAY...SURFACE LOW SHOULD CROSS FROM KS INTO THE CAROLINAS. BY THE GFS THE BEST FORCING SHOULD BE WELL SOUTH OF OUR REGION, OTHER THAN MID LEVEL QVEC CONVERGENCE. THEREFORE, AGREE WITH THE PREVIOUS SHIFT THAT THE GFS IS TOO FAR NORTH WITH THE QPF. DESPITE BEING ON THE NORTH SIDE OF THIS LOW, THE COMBINATION OF DOWNSLOPING WINDS AND AIR MASS MODIFICATION SHOULD HELP TO KEEP TEMPS NEAR OR JUST BELOW NORMAL BOTH DAYS. THE CURRENT CLOSED LOW OVER ONTARIO THAT IS GOING TO HELP STEER THE WEEKEND SFC SYSTEM WELL TO OUR SOUTH IS PREDICTED TO RETROGRADE WESTWARD OR REMAIN NEARLY STATIONARY TO START NEXT WEEK. SOME INSTABILITY SHOWERS ARE POSSIBLE UNDER THIS COLD POOL. BUT THE THERMAL PROFILE CLOSER TO THE SURFACE WILL BE MILDER. SO WHILE TEMPS SHOULD STILL BE BELOW NORMAL, THEY SHOULD BE A CATEGORY OR TWO HIGHER THAN TODAY AND FRIDAY. WE LEFT IN THE CHANCE FOR RAIN ON WEDNESDAY ASSOCIATED WITH THE NEXT LOW PRESSURE SYSTEM/POSSIBLE NOR`EASTER. STILL CONSIDERABLE UNCERTAINTY AND MODEL DIFFERENCES ON THIS SYSTEM, SO STAYED CLOSE TO THE PREVIOUS FORECAST.
-- End Changed Discussion --
&& .AVIATION /15Z THURSDAY THROUGH MONDAY/...
-- Changed Discussion --
THE FOLLOWING DISCUSSION IS FOR KPHL, KPNE, KTTN, KABE, KRDG, KILG, KMIV, KACY AND SURROUNDING AREAS. VFR CONDITIONS WILL CONTINUE AT THE TAF SITES THROUGH THE PERIOD, ALTHOUGH CLOUD COVER WILL INCREASE THIS AFTERNOON INTO TONIGHT. A FEW VERY LIGHT RAIN SHOWERS/SPRINKLES WILL BE POSSIBLE THIS AFTERNOON PRIMARILY FOR KTTN AND KABE. HOWEVER, VFR CONDITIONS ARE EXPECTED TO CONTINUE EVEN UNDER THESE SHOWERS. WINDS WILL BE THE MAIN CONCERN AS WIND GUSTS WILL INCREASE THROUGH THE DAY AND WILL GUST AROUND 25 KNOTS AT TIMES TODAY. THE SPEED OF THE GUSTS MAY DROP OFF A BIT THIS EVENING AND OVERNIGHT, BUT WE COULD STILL GET SOME GUSTS ROUND 20 KNOTS THROUGH THE NIGHT FOR MANY AREAS. OUTLOOK... FRIDAY...VFR CONDITIONS EXPECTED, GUSTY NORTHWESTERLY WINDS (UP TO 25 KT), ESPECIALLY LATE MORNING AND THROUGH THE AFTERNOON. FRIDAY NIGHT...VFR CONDITIONS WITH LIGHTER WINDS. SATURDAY AND SATURDAY NIGHT...MAINLY VFR CONDITIONS NORTHERN AIRPORTS AND TERMINALS. SOME RAIN AND SUB-VFR CONDITIONS ARE POSSIBLE, MAINLY SOUTH OF A KILG/KACY LINE. SUNDAY THROUGH MONDAY...MAINLY VFR CONDITIONS ARE EXPECTED.
-- End Changed Discussion --
&& .MARINE...
-- Changed Discussion --
THE SMALL CRAFT ADVISORY REMAINS IN EFFECT FOR TODAY AND TONIGHT AS WINDS WILL REMAIN ELEVATED WITH THE PRESSURE GRADIENT REMAINING ACROSS THE AREA AND SOME WINDS FROM ALOFT MIXING DOWN TO THE SURFACE. WITH THE NORTHWEST FLOW, SEAS ARE NOT EXPECTED TO BUILD SIGNIFICANTLY AND SHOULD BE AROUND 4-5 FEET. OUTLOOK... FRIDAY AND FRIDAY NIGHT...SCA CONDITIONS CONTINUE ON ALL WATERS THROUGH THE DAY FRIDAY AND MAY LINGER INTO FRIDAY EVENING. SATURDAY THROUGH SUNDAY...SUB SMALL CRAFT ADVISORY CONDITIONS EXPECTED. THE LOW PRESSURE SYSTEM SHOULD PASS TOO FAR TO THE SOUTH TO GENERATE HIGHER SEAS OR WINDS. SUNDAY NIGHT THROUGH MONDAY...CONTINUED SUB-SCA CONDITIONS; ALTHOUGH, SOME WIND GUSTS TO AROUND 20 KNOTS PLUS ARE POSSIBLE.
-- End Changed Discussion --
&& .FIRE WEATHER... DRY AND GUSTY CONDITIONS ARE EXPECTED TODAY WITH RH VALUES EXPECTED TO DIP INTO THE MID/UPPER 20S AND WINDS GUSTING AROUND 25-30 MPH. AFTER COORDINATION WITH THE STATE PARTNERS HAVE DECIDED TO ISSUE A SPS FOR TODAY AS FINE FUELS ARE ALREADY BEGINNING TO DRY OUT. THE SPS IS VALID THROUGH 7 PM EDT AS WE SHOULD SEE QUICK RH RECOVERY EARLY THIS EVENING. CONDITIONS MAY BE ENHANCED ON FRIDAY FOR THE POTENTIAL OF WILDFIRE SPREAD ACROSS THE REGION. FRIDAY`S RELATIVE HUMIDITY VALUES ARE PROGGED TO DROP BELOW 30 PERCENT FOR A TIME FROM LATE FRIDAY MORNING AND THROUGH THE AFTERNOON TO EARLY EVENING. IN ADDITION, SUSTAINED WEST-NORTHWEST WINDS BETWEEN 15 TO 20 MPH ARE FORECAST DURING THIS TIMEFRAME, WITH GUSTS REACHING BETWEEN 25 TO 30 MPH AT TIMES. WE WILL CONTINUE TO MONITOR THE LATEST GUIDANCE AND COORDINATE WITH OUR FIRE WEATHER PARTNERS IF ANY ADDITIONAL PRODUCTS BECOME NECESSARY. && .PHI WATCHES/WARNINGS/ADVISORIES... PA...FREEZE WATCH FROM LATE FRIDAY NIGHT THROUGH SATURDAY MORNING FOR PAZ060>062-101>106. FREEZE WARNING FROM 2 AM TO 9 AM EDT FRIDAY FOR PAZ061-062-105. FREEZE WATCH FROM LATE TONIGHT THROUGH FRIDAY MORNING FOR PAZ060-101>104-106. NJ...FREEZE WATCH FROM LATE FRIDAY NIGHT THROUGH SATURDAY MORNING FOR NJZ001-007>010-012-013-015>022-027. FREEZE WARNING FROM 2 AM TO 9 AM EDT FRIDAY FOR NJZ001-007>010. FREEZE WATCH FROM LATE TONIGHT THROUGH FRIDAY MORNING FOR NJZ012-013-015>022-027. DE...NONE. MD...NONE. MARINE...SMALL CRAFT ADVISORY UNTIL 6 PM EDT FRIDAY FOR ANZ430-431- 450>455. && $$ SYNOPSIS...GIGI/KLINE NEAR TERM...JOHNSON/ROBERTSON SHORT TERM...ROBERTSON LONG TERM...GIGI/JOHNSON AVIATION...GIGI/JOHNSON/KLINE/ROBERTSON MARINE...GIGI/JOHNSON/KLINE/ROBERTSON FIRE WEATHER...JOHNSON/ROBERTSON/GIGI

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