121 FXUS61 KOKX 190832 CCA AFDOKX AREA FORECAST DISCUSSION...CORRECTED NATIONAL WEATHER SERVICE NEW YORK NY 427 AM EDT FRI JUL 19 2013 .SYNOPSIS... A TROUGH OF LOW PRESSURE WILL LINGER OVER THE AREA THROUGH TONIGHT. A PRE-FRONTAL TROUGH MOVES ACROSS THE AREA SATURDAY AHEAD OF A COLD FRONT...WHICH PUSHES SOUTH THROUGH THE TRI-STATE SATURDAY NIGHT. HIGH PRESSURE BUILDS OVER THE REGION IN THE WAKE OF THE COLD FRONT TO START THE WEEK. LOW PRESSURE THEN MOVES INTO THE NORTHEASTERN UNITED STATES DURING THE MIDDLE OF THE WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... MAJOR ISSUE TODAY IS THE HEAT. 850 TEMPERATURES ARE FORECAST TO BE ABOUT 1C HIGHER TODAY THAN YESTERDAY...WHICH SHOULD CORRESPOND TO HIGHS BEING 1-2F WARMER THAN YESTERDAY AS WELL. THIS THINKING IS CONSISTENT WITH THE RESULTS OF A BLEND OF MIXING DOWN FROM 875 HPA NEAR SHORE...850 HPA OVER NE NJ/LOWER HUDSON VALLEY...AND 825 HPA OVER MOST OF S CT PER BUFKIT SOUNDINGS...WITH NAM 2-METER TEMPERATURES AND A BLEND OF MAV/MET GUIDANCE. EXPECT POCKETS OF HIGHS AT OR A DEGREE OR SO ABOVE 100 ACROSS URBAN PORTIONS OF NE NJ...THE NORMALLY HOTTER SECTIONS OF NYC...AND MORE URBANIZED AREAS IN INTERIOR S CT...WITH MAINLY MID TO UPPER 90S ELSEWHERE. THE BOUNDARY LAYER FLOW STARTS OF WSW AND DOES NOT REALLY BECOME SSW UNTIL EARLY AFTERNOON...SO EVEN COASTAL AREAS SHOULD HAVE TIME TO GET TO AT LEAST THE LOWER IF NOT THE MID 90S. SOUNDINGS STILL SHOW THAT WE SHOULD MIX DOWN SOME LOWER DEWPOINTS IN THE AFTERNOON...BUT WITH THE STARTING POINT THE LOWER TO MID 70S...AND SOME LOW LEVEL MOISTENING ON STRENGTHENING SW-SSW BOUNDARY LAYER FLOW...SHOULD ONLY SEE A FALL OFF OF A FEW DEGREES. SO A COMBINATION OF HIGHS MAINLY FROM THE MID 90S TO AROUND 100 AND DEWPOINTS MAINLY IN THE LOWER 70S YIELDS HEAT INDICES FROM 105 TO 109 ACROSS A LARGE PORTION OF THE TRI-STATE. HAVE EXPANDED THE EXCESSIVE HEAT WARNING ACCORDINGLY...LEAVING ONLY NEW LONDON...EASTERN SUFFOLK AND SOUTHERN MIDDLESEX COUNTIES IN THE ADVISORY. SOME POTENTIAL FOR ADVISORY TO BE REACHED IN ADVISORY AREA...ESPECIALLY IN CT...BUT CONFIDENCE IN THIS IS NOT AT REQUIRED 80 PERCENT LEVEL TO EXTEND THE WARNING INTO THESE AREAS AS WELL. HAVE SLIGHT CHANCE POPS LATE THIS AFTERNOON/EARLY THIS EVENING ACROSS FAR NW ZONES TO GO WITH THERMAL SURFACE TROUGH AND PASSING 500 HPA SHORTWAVE. HOWEVER...THERE WILL ALSO BE NEGATIVE VORTICITY ADVECTION AT 700 HPA AND A WEAK CAP AROUND 650 HPA DURING THIS TIME FRAME...SO THE ENTIRE AREA COULD REMAIN DRY AS A RESULT. THERE IS A MODERATE RISK OF RIP CURRENTS AT ATLANTIC FACING BEACHES INTO THIS EVENING. && .SHORT TERM /6 PM THIS EVENING THROUGH SATURDAY NIGHT/... SW FLOW ALOFT TONIGHT...WITH WSW BOUNDARY LAYER FLOW OF 10-20 KT WITH SOME DOWNSLOPE COMPONENT. ALSO WILL HAVE PERSISTENT NEGATIVE VORTICITY ADVECTION AT 700 HPA. SO OUTSIDE OF ANY LINGERING EVENING SHRA/TSTM OVER FAR NW ZONES EARLY IN THE EVENING...IT SHOULD BE DRY TONIGHT. IT WILL BE YET ANOTHER VERY WARM AND MUGGY NIGHT...WITH LOWS MAINLY FROM THE MID 70S TO AROUND 80 - CONSISTENT WITH A BLEND OF MAV/MET GUIDANCE WITH NAM 2-METER TEMPERATURES. TWO WEATHER RELATED THREATS ON SATURDAY. THE FIRST IS CONTINUED HIGH LEVELS OF HEAT AND HUMIDITY. 850 TEMPERATURES ARE FORECAST TO COOL OFF 1-2C FROM TODAY SO HIGHS SHOULD BE AT LEAST 2-4F COOLER...PLUS WILL HAVE MORE CLOUD COVER WITH CONVECTIVE DEBRIS CLOUDS MOVING IN AHEAD OF AN ADVANCING COLD FRONT. THIS THINKING ALIGNS WELL WITH A BLEND OF MIXING DOWN FORM 850 HPA NEAR THE COAST AND 875 HPA INLAND...WITH NAM 2-METER TEMPERATURES AND MAV/MET GUIDANCE...WITH HIGHS MAINLY FROM AROUND 90 TO THE MID 90S - WARMEST THE NYC METRO. THESE TEMPERATURES COUPLED WITH DEWPOINTS IN THE LOWER 70S WILL LIKELY NECESSITATE HEAT ADVISORIES FOR NYC/NE NJ AND MOST OF THE REMAINDER OF URBAN/SUBURBAN PARTS OF THE NYC METRO AREA AS WELL. HOWEVER...WITH AN EXCESSIVE HEAT WARNING ALREADY UP IN THESE AREAS FOR TODAY...DID NOT WANT TO PROMOTE ANY CONFUSION BY ISSUING THE HEAT ADVISORY FOR TOMORROW AS WELL. THE SECOND THREAT FROM LATE SATURDAY MORNING INTO SATURDAY NIGHT IS THE THREAT OF SEVERE WEATHER ASSOCIATED WITH THE PASSAGE OF A COLD FRONT AND THE PASSING TO THE NORTH OF A NORTHERN STREAM SHORTWAVE. THREAT DOES NOT LOOK QUITE AS ROBUST AS IT HAS PREVIOUSLY...AS CAPE IS NOW ONLY FORECAST TO BE 1500-2500 J/KG AND SHEAR OF 15-25 KT...WITH BULK RICHARDSON NUMBERS OF 55 OR HIGHER...SUPPORTING MAINLY PULSE CONVECTION ORIGINATING OVER THE AREA. HOWEVER STORM MOTION WOULD STILL BRING STORMS FORMING OVER WESTERN NY DOWN INTO THE TRI- STATE...AND THIS IS AN AREA WHERE THERE IS MORE SHEAR...SO THERE IS THE POTENTIAL FOR BOWING SEGMENTS TO FORM THERE AND THEN MOVE INTO THE AREA. AS THE RESULT...THERE STILL IS THE RISK OF DAMAGING WINDS IF THESE BOWING SEGMENTS MOVE IN. REFER TO THE HYDROLOGY SECTION OF THE AFD FOR THE ASSOCIATED HYDROLOGIC THREAT. HAVE LIKELY POPS FROM NW T SE FROM SATURDAY AFTERNOON INTO SATURDAY EVENING...TAPERING OFF TO SLIGHT CHANCE THROUGHOUT AFTER MIDNIGHT...WITH FAR NW AREAS LIKELY GOING DRY. FOR LOWS SATURDAY NIGHT USED A BLEND OF MAV/MET GUIDANCE WITH NAM 2-METER TEMPERATURES. THESE VALUES SHOULD BE AROUND 5 DEGREES ABOVE NORMAL...AND SHOULD BE THE LAST MUGGY NIGHT EXPERIENCED FOR AT LEAST A FEW DAYS. && .LONG TERM /SUNDAY THROUGH THURSDAY/... A RETURN TO MORE SEASONABLE WEATHER BY SUNDAY AS THE COLD FRONT PUSHES THROUGH AND SURFACE HIGH PRESSURE BUILDS IN BEHIND. GENERAL MODEL AGREEMENT THE COLD FRONT STALLS JUST SOUTH OF THE AREA SUNDAY INTO THE BEGINNING OF THE COMING WORK WEEK. BROAD UPPER LEVEL TROUGHING PERSISTS THROUGH SUNDAY AS WELL. MULTIPLE WEAK VORT MAXES TRAVERSE THE AREA SUNDAY...AND WITH THE FRONT IN THE VICINITY...WILL KEEP A SLIGHT CHANCE POPS IN THE FORECAST DURING THE DAY...FINALLY DRYING OUT FOR A SHORT PERIOD SUNDAY NIGHT AS WEAK RIDGING ATTEMPTS TO BUILD IN BRIEFLY. WITH THE COOLER...DRIER AIR SLOW TO ADVECT IN THE WAKE OF THE FRONT...PLENTY OF WARM...MOIST AIR REMAINS IN PLACE DURING THE DAY TO WARRANT THE MENTION OF THUNDER WITH INSTABILITY VALUES AROUND 500 J/KG. THE CHANCE FOR PCPN REMAINS IN THE FORECAST FOR THE COMING WEEK WITH A DEEPENING TROUGH SETTING UP ACROSS THE EASTERN US...BRINGING THROUGH MULTIPLE SHORTWAVES. A BIT MORE MODEL DIVERGENCE AT THE SURFACE ON THE HANDLING OF THE COLD FRONT AND THE NEXT DEVELOPING LOW. FORTUNATELY THE 00Z ECMWF CAME IN MORE IN LINE WITH THE OTHER GLOBAL MODELS...UNLIKE THE 12Z RUN...INCREASING THE CONFIDENCE A LOW FORMS AROUND THE DELMARVA REGION MONDAY AND RIDES A NOW NEAR STATIONARY FRONT TO THE NORTHEAST THROUGH MIDWEEK. ECMWF IS ACTUALLY A TAD MORE PROGRESSIVE THAN THE GFS/CMC...SO SIDED WITH THE SLIGHTLY SLOWER SOLUTION. A WEAK COLD FRONT ASSOCIATED WITH THE LOW ALSO PASSES THROUGH WED. MAINTAINED SLIGHT CHANCE POPS MON...INCREASING TO CHANCE FOR TUES-THURS...THEN BACK TO SLIGHT CHANCE TO END THE WEEK. GENERALLY EXPECTING BOTH SHOWERS AND TSTMS...THOUGH AT THIS TIME NOT SEEING ANYTHING IN THE STRONG TO SEVERE WHELM FOR THE TSTM. AFTER BEING THE MAIN STORY FOR A WEEK...TEMPS WILL RETURN TO NEAR NORMAL WITH HIGHS IN THE 80S AND LOWS IN THE 60S TO AROUND 70 IN NYC...AND DEWPOINTS HOVERING MAINLY IN THE MID 60S. SOUTHERLY WINDS BY THE END OF THE WEEK WILL BEGIN TO ADVECT IN WARMER...MORE MOIST AIR...THOUGH NO HEAT CONCERNS AT THIS TIME WITH HIGHEST HEAT INDICES REMAINING NEAR THE ACTUAL HIGH TEMPS EACH DAY. && .AVIATION /07Z FRIDAY THROUGH TUESDAY/... MAINLY VFR THROUGH THE TAF PERIOD. ONLY EXCEPTION IS KGON...KBDR AND PERHAPS KSWF IN HZ/BR THROUGH 13Z OR SO. MODERATE TO HIGH CONFIDENCE IN WIND FORECAST. ISOLATED TSTMS POSSIBLE IN AFTN/EVE AS WELL. NY METRO ENHANCED AVIATION WEATHER SUPPORT... DETAILED INFORMATION...INCLUDING HOURLY TAF WIND COMPONENT FCSTS CAN BE FOUND AT: HTTP://WWW.ERH.NOAA.GOV/ZNY/N90 (LOWER CASE) KJFK FCSTER COMMENTS: MODERATE TO HIGH CONFIDENCE IN WIND FORECAST. KLGA FCSTER COMMENTS: TIMING OF START/END OF GUSTS MAY BE +/- 1-2 HOURS AND MAY BE A FEW KT HIGHER AFT 19Z. KEWR FCSTER COMMENTS: TIMING OF START/END OF GUSTS MAY BE +/- 1-2 HOURS AND MAY BE A FEW KT HIGHER AFT 19Z. THE AFTERNOON KEWR HAZE POTENTIAL FORECAST IS GREEN...WHICH IMPLIES SLANT RANGE VISIBILITY 7SM OR GREATER OUTSIDE OF CLOUD. KTEB FCSTER COMMENTS: TIMING OF START/END OF GUSTS MAY BE +/- 1-2 HOURS AND MAY BE A FEW KT HIGHER AFT 19Z. KHPN FCSTER COMMENTS: TIMING OF START/END OF GUSTS MAY BE +/- 1-2 HOURS AND MAY BE A FEW KT HIGHER AFT 20Z. KISP FCSTER COMMENTS: TIMING OF START/END OF GUSTS MAY BE +/- 1-2 HOURS AND MAY BE A FEW KT HIGHER AFT 20Z. .OUTLOOK FOR 06Z SATURDAY THROUGH TUESDAY... .FRI NIGHT...MAINLY VFR (PATCHY MVFR HZ/BR). .SAT...MAINLY VFR...BUT THE POTENTIAL LIES FOR WITH MVFR OR LOWER CONDITIONS IN POSSIBLE STRONG TO SEVERE CONVECTION LATE AFTERNOON/EVENING. .SUN...LINGERING SHRA POSSIBLE WITH SUB-VFR CONDITIONS...MAINLY IN THE MORNING. .MON AND TUE...MAINLY VFR. && .MARINE... INCREASING SW FLOW AHEAD OF A COLD FRONT...AND PERSISTENT S SWELL WILL BRING SEAS TO SCA LEVELS ON THE COASTAL OCEAN WATERS FROM TONIGHT THROUGH AT LEAST SATURDAY NIGHT. THERE IS THE LIKELIHOOD OF OCCASIONAL GUSTS TO 25 KT THIS AFTERNOON OVER THE COASTAL OCEAN WATERS AND FREQUENT GUSTS TO 25 KT TONIGHT. AS A RESULT HAVE EXTENDED THE SCA FROM TONIGHT THROUGH SATURDAY OVER THE COASTAL OCEAN WATERS. OVER THE REMAINDER OF THE WATERS...WINDS SHOULD REMAIN 15-20 KT OR LESS...WITH MAYBE SOME OCCASIONAL GUSTS TO 25 KT THIS AFTERNOON AND TONIGHT NEAR SHORE. SEAS SHOULD BE 2 FT OR LESS THROUGH SATURDAY NIGHT. GENERALLY A LIGHT FLOW OVER ALL THE WATERS THROUGH THE COMING WEEK KEEP WIND GUSTS BELOW 20 KTS. SEAS ON SUNDAY WILL REMAIN AROUND 5 FT ON THE EASTERN OCEAN WATERS...BUT EXPECTING AS THE HIGH SETS UP OVER THE REGION FOR SEAS TO DROP BELOW SCA CRITERIA BY MONDAY. SEAS THEN STAY MAINLY SUB-SCA FOR THE WEEK...WITH A CHANCE OF 5 FT SEAS AGAIN ON THE OCEAN FOR A PERIOD TUES IF THE EASTERLY FLOW PERSISTS LONG ENOUGH. && .HYDROLOGY... IT SHOULD MAINLY BE DRY THROUGH TONIGHT...THOUGH AN ISOLD SHRA/TSTM OVER FAR NW PORTIONS OF THE TRI-STATE LATE THIS AFTERNOON/EARLY THIS EVENING CANNOT BE COMPLETELY RULED OUT. THERE IS POTENTIAL FOR 1/4 TO 2/3 OF AN INCH OF BASIN AVERAGE RAINFALL WITH THE COLD FRONT PASSAGE SATURDAY/SATURDAY NIGHT...WITH LOCALLY HIGHER AMOUNTS POSSIBLE. IF THESE LOCALLY HIGHER AMOUNTS ARE REALIZED...MINOR FLOODING OF MAINLY URBAN AND POOR DRAINAGE IS POSSIBLE. NO SIGNIFICANT PRECIPITATION IS EXPECTED THROUGH THE UPCOMING WEEK. && .CLIMATE... RECORD MAXIMUM MINIMUM TEMPERATURES FOR JULY 19TH SITE RECORD YEAR FORECAST LOW NYC 81 1878 82 BDR 77 2008 80 ISP 76 2008 78 LGA 81 2008 84 JFK 77 1982 81 EWR 80 1982 82 RECORD MAXIMUM TEMPERATURES FOR JULY 19TH SITE RECORD YEAR FORECAST HIGH NYC 102 1977 99 BDR 96 1991 96 ISP 92 1999 96 LGA 99 1977 101 JFK 97 1963 96 EWR 100 1999* 102 *ALSO OCCURRED IN PREVIOUS YEARS && .OKX WATCHES/WARNINGS/ADVISORIES... CT...HEAT ADVISORY FROM 11 AM THIS MORNING TO 8 PM EDT THIS EVENING FOR CTZ008-011-012. EXCESSIVE HEAT WARNING FROM 11 AM THIS MORNING TO 8 PM EDT THIS EVENING FOR CTZ005>007-009-010. NY...HEAT ADVISORY FROM 11 AM THIS MORNING TO 8 PM EDT THIS EVENING FOR NYZ079-081. EXCESSIVE HEAT WARNING FROM 11 AM THIS MORNING TO 8 PM EDT THIS EVENING FOR NYZ067>075-078-080-176>179. NJ...EXCESSIVE HEAT WARNING FROM 11 AM THIS MORNING TO 8 PM EDT THIS EVENING FOR NJZ002-004-006-103>108. MARINE...SMALL CRAFT ADVISORY FROM 6 PM THIS EVENING TO 6 PM EDT SATURDAY FOR ANZ350-353-355. && $$ SYNOPSIS...MALOIT/SEARS NEAR TERM...MALOIT SHORT TERM...MALOIT LONG TERM...SEARS AVIATION...24 MARINE...MALOIT/SEARS HYDROLOGY...MALOIT CLIMATE...MALOIT