487
FXUS61 KOKX 182054
AFDOKX
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW YORK NY
454 PM EDT THU JUL 18 2019
SYNOPSIS
A WEAK COLD FRONT SAGS SLOWLY SOUTH OF THE WATERS THROUGH TONIGHT,
WASHING OUT AS IT DOES SO. THE AREA WILL THEN COME UNDER THE
INFLUENCE OF THE WESTERN EXTENT OF THE BERMUDA HIGH THROUGH THE
WEEKEND. A COLD FRONT APPROACHES AND MOVES THROUGH SUNDAY NIGHT
INTO MONDAY. HIGH PRESSURE RETURNS FOR TUESDAY AND WEDNESDAY.
NEAR TERM /UNTIL 6 PM THIS EVENING/
A STALLED FRONTAL BOUNDARY ACROSS LONG ISLAND EARLY THIS
EVENING WILL SLOWLY DROP TO THE SOUTH. PRIOR TO THAT TIME, WEAK
WARM ADVECTION JUST TO THE NORTH OF THE BOUNDARY AND THE FRONT
ITSELF WILL SERVE AS A FOCUS FOR SCATTERED SHOWERS AND POSSIBLY
A THUNDERSTORM. EARLIER, THERE WERE REPORTS OF URBAN AND POOR
DRAINAGE FLOODING ALONG THE CT COAST. THE HEAVIEST ACTIVITY HAS
SINCE WORKED EAST OF THE AREA.
AIRMASS IS MOISTURE LOADED WITH PW VALUES OVER 2 INCHES AND
MARGINAL INSTABILITY. WIND SHEAR IS WEAK, SO THE MAIN THREAT
WILL BE BRIEF HEAVY DOWNPOURS AND LOCALIZED URBAN AND POOR
DRAINAGE FLOODING. A FEW SHOWERS MAY LINGER THROUGH THE
OVERNIGHT DUE TO WEAK LIFT AS A FRONTAL PASSES JUST SOUTH OF
THE AREA AND WEAK MID LEVEL SHORTWAVES TRAVERSE THE SOUTHERN
EDGE OF THE WESTERLIES.
IT WILL BE A WARM, HUMID NIGHT WITH READINGS RANGING FROM THE
MID AND UPPER 60S INLAND, TO THE LOWER AND MID 70S ACROSS THE
NYC METRO. THERE IS SOME HINT OF COOLER TEMPERATURES WORKING IN
ON THE A LIGHT N/NE FLOW OVERNIGHT BEHIND THE FRONT AND WAVE.
THESE READINGS ARE NEAR 5 DEGREES ABOVE NORMAL.
SHORT TERM /6 PM THIS EVENING THROUGH 6 PM FRIDAY/
FORECAST AREA WILL RESIDE AT THE SOUTHERN EDGE OF THE WESTERLIES
WITH THE POTENTIAL FOR RECORD WARMTH AS WE HEAD INTO THE
WEEKEND. THIS WILL BE THE START OF A HEAT WAVE FOR THE REGION
FOLLOWING THE CLOUD COVER AND SHOWERS THAT TEMPERED THE
TEMPERATURES ON THURSDAY.
DEEP-LAYERED W FLOW AND THE WESTWARD EXPANSION OF THE SUBTROPICAL
HIGH ALONG THE EAST COAST WILL COMBINE TO KEEP THE AIRMASS VERY
HUMID WITH DEW POINTS INTO THE LOWER AND MIDDLE 70S ON FRIDAY.
THIS COMBINED WITH HIGHS IN THE LOWER AND MIDDLE 90S FROM NYC
AND POINTS NORTH AND WEST WILL PRODUCE HEAT INDEX VALUES AROUND
105 ON FRIDAY FOR THE NYC METRO, NE NJ, AND THE LOWER HUDSON
VALLEY. AN EXCESSIVE HEAT WARNING HAS BEEN ISSUED FOR THESE
AREAS. TO THE EAST, A DEVELOPING ONSHORE FLOW WILL KEEP
TEMPERATURES COOLER, MAINLY IN THE UPPER 80S TO NEAR 90. STILL
THOUGH, HEAT INDEX VALUES WILL RANGE FROM MID 90S TO AROUND 100.
THESE LOCATIONS ARE UNDER A HEAT ADVISORY. THIS WILL BEGIN A
PROLONGED PERIOD OF HEAT HAZARDS FOR THE REGION.
ADDITIONALLY, SOME OF THE CAMS ARE NOT HINTING AT LATE DAY
CONVECTION DROPPING IN FROM THE NW DURING THE LATE
AFTERNOON/EARLY EVENING HOURS. HIGH CAPE, WEAK SHEAR
ENVIRONMENT WITH LACK OF A STRONG TRIGGER LENDS ONLY TO AN ISOLATED
MENTION IN THE FORECAST AT THIS TIME. HOWEVER, ANY STORM BREAKING
THE CAP COULD BE STRONG TO SEVERE WITH THE MAIN THREAT BE
LOCALIZED DAMAGING WINDS.
FOR FRIDAY NIGHT, NOT MUCH RELIEF WITH TEMPERATURES STRUGGLING
TO GET INTO THE 70S. HEAT INDEX VALUES OVERNIGHT MAY GET NO
LOWER THAN THE MID TO UPPER 80S FOR THE NYC METRO AREA.
THERE IS A MODERATE RIP CURRENT RISK AT THE OCEAN BEACHES FOR
FRIDAY.
LONG TERM /FRIDAY NIGHT THROUGH THURSDAY/
THE MAIN CONCERN FOR THIS PERIOD CONTINUES TO BE THE HIGH HEAT AND
HUMIDITY THAT IS EXPECTED TO CONTINUE SATURDAY AND SUNDAY THANKS TO
A BERMUDA HIGH OVER THE NORTHERN ATLANTIC. 850 HPA TEMPERATURE
ANOMALIES OF +2-+3C OVER THE GREAT LAKES REGION WILL MOVE OVER THE
AREA THROUGH SUNDAY. 500 HPA HEIGHTS OVER 5900 M ALSO NOTED IN
GUIDANCE FOR SATURDAY, WITH SLIGHTLY LESS VALUES FOR SUNDAY. THIS IS
IN LINE WITH CLIMATOLOGY FOR A WIDESPREAD HEAT WAVE TO IMPACT THE
FORECAST AREA FROM FRIDAY THROUGH SUNDAY. MUCH OF THE GUIDANCE
SUGGESTS HIGHS WELL INTO THE THE 90S DURING THIS TIME FRAME, WITH
DEW POINTS WELL INTO THE 70S.
HIGHS ON SATURDAY WILL RANGE FORM 95 TO 100 DEGREES, WITH PERHAPS
ISOLATED AREAS IN NORTHEAST NEW JERSEY REACHING A DEGREE OR TWO
ABOVE THE CENTURY MARK. SUNDAY WILL BE SLIGHTLY COOLER, AS HEIGHTS
LOWER SOMEWHAT, BUT IT WILL CONTINUE TO BE VERY HOT AND HUMID. THERE
IS ALSO A GREAT DEAL OF UNCERTAINTY WITH THE TEMPERATURES FOR SUNDAY
DUE TO UNCERTAINTY IN CLOUD COVERAGE FROM AN APPROACHING COLD FRONT
TO THE WEST. THE ECMWF ENSEMBLE HAS A RANGE OF HIGH TEMPERATURES
FROM 89 TO 101 FOR CENTRAL PARK.
REGARDLESS, WITH ANOMALOUSLY HIGH DEW POINTS IN THE MIDDLE TO UPPER
70S IN SOME CASES, THIS TRANSLATES TO HEAT INDEX VALUES OF 105 TO
JUST OVER 110 FOR MUCH OF THE FORECAST AREA (ISOLATED PORTIONS OF
NORTHEAST NEW JERSEY MAY SEE HEAT INDEX VALUES OF 115) FOR SATURDAY.
EXCESSIVE HEAT WATCHES HAVE BEEN CONVERTED TO EXCESSIVE HEAT
WARNINGS FOR SATURDAY. WITH THE POTENTIAL FOR WIDESPREAD HEAT INDEX
VALUES OF 105-110 ON SUNDAY, EXCESSIVE HEAT WARNINGS HAVE BEEN
ISSUED FOR THEN AS WELL. THESE TEMPERATURES AND HEAT INDEX VALUES
ARE LIFE THREATENING, PLEASE FOLLOW THE PREPAREDNESS/PRECAUTIONARY
ACTIONS WITHIN OUR EXCESSIVE HEAT WARNING PRODUCTS TO PREPARE FOR
THE UPCOMING HEAT.
OF ADDITIONAL CONCERN ARE NIGHTTIME LOWS SATURDAY NIGHT INTO SUNDAY,
AS LOWS ARE NOT FORECAST TO DIP BELOW 80 IN THE NEW YORK CITY METRO
AREA, WITH THE LOWEST FORECAST HEAT INDEX VALUES DURING THAT TIME
FRAME IN THE UPPER 80S TO LOWER 90S.
AS FOR PRECIPITATION, THERMAL TROUGHS DEVELOPING WILL ALLOW FOR JUST
A PASSING SHOWER OR THUNDERSTORM FOR LATE SATURDAY INTO SATURDAY
NIGHT. AN APPROACHING COLD FRONT WILL BRING A LOW END CHANCE FOR
SHOWERS AND THUNDERSTORMS SUNDAY AFTERNOON, MAINLY FOR NEW YORK CITY
AND POINTS NORTH AND WEST. AS FOR NOW, NOTHING INDICATING A
WIDESPREAD SEVERE EVENT IN THE LONG TERM. CHANCES INCREASE SUNDAY
NIGHT INTO MONDAY, WITH BEST CHANCES FOR RAIN MONDAY AFTERNOON AS
THE COLD FRONT REMAINS JUST OFF SHORE. THERE MAY BE LINGERING
SHOWERS AND THUNDERSTORMS FOR TUESDAY, MAINLY FOR SOUTHERN PORTIONS
OF THE AREA. TEMPERATURES WILL BE COOLER FOR MONDAY THANKS TO
INCREASE CLOUDINESS AND RAIN, WITH LOWER HUMIDITY LEVELS. MORE
SEASONABLE CONDITIONS ARE EXPECTED FOR TUESDAY THROUGH THURSDAY WITH
HIGH PRESSURE IN CONTROL FOR THE MIDDLE OF THE WEEK.
AVIATION /20Z THURSDAY THROUGH TUESDAY/
MVFR TO IFR CONDITIONS GENERALLY PREVAILING ACROSS THE AREA. A
RETURN TO IFR/LIFR CONDITIONS EXPECTED THIS EVENING. SCATTERED
SHOWERS WILL PREVAIL ACROSS THE AREA WHICH MAY REDUCED
VISIBILITIES AT TIMES. A STRONG CLUSTER OF TSTMS ACROSS CENTRAL
AND SOUTH NEW JERSEY SHOULD CONTINUE TO MOVE EAST AND STAY SOUTH
OF THE NYC TERMINALS BUT WILL KEEP A CHANCE OF THUNDERSTORMS
KJFK/KEWR/KTEB WITH VCTS DUE TO IMPACTS TO AIR TRAVEL. SHOWERS
END THIS EVE WITH THE FRONT PUSHING SOUTH OF LONG ISLAND.
A LIGHT, GENERALLY LESS THAN 10 KT E-NE FLOW IS EXPECTED ACROSS THE
TERMINALS WITH A COASTAL SEA BREEZE VEERING WIND TO THE SE AT TIMES
AT KJFK.
WINDS SWITCH TO W-SW NEAR 10 KT AROUND 15Z ON FRIDAY AND VFR IS
EXPECTED TO RETURN. TIMING COULD BE OF A FEW HOURS, ESPECIALLY AT
KLGA WHERE A EASTERLY COMPONENT TO THE WIND MAY HANG ON A FEW HOURS
LONGER.
..NY METRO ENHANCED AVIATION WEATHER SUPPORT
DETAILED INFORMATION, INCLUDING HOURLY TAF WIND COMPONENT FCSTS, CAN
BE FOUND AT: HTTP:/WWW.WEATHER.GOV/ZNY/N90
KJFK TAF COMMENTS: AMENDMENTS POSSIBLE FOR CHANGING FLIGHT
CATEGORIES.
KLGA TAF COMMENTS: AMENDMENTS POSSIBLE FOR CHANGING FLIGHT
CATEGORIES.
KEWR TAF COMMENTS: AMENDMENTS POSSIBLE FOR CHANGING FLIGHT
CATEGORIES.
KTEB TAF COMMENTS: AMENDMENTS POSSIBLE FOR CHANGING FLIGHT
CATEGORIES.
KHPN TAF COMMENTS: AMENDMENTS POSSIBLE FOR CHANGING FLIGHT
CATEGORIES.
KISP TAF COMMENTS: AMENDMENTS POSSIBLE FOR CHANGING FLIGHT
CATEGORIES.
OUTLOOK FOR 21Z FRIDAY THROUGH TUESDAY
21Z FRIDAY THROUGH SUNDAY
VFR. ISOLATED SHRA/TSTMS POSSIBLE
SUNDAY ESPECIALLY LATE
MONDAY AND TUESDAY
MVFR POSSIBLE IN SCATTERED SHOWERS AND
THUNDERSTORMS.
MARINE
EASTERLY WINDS AHEAD OF FRONTAL WAVE COULD BRIEFLY PRODUCE GUSTS
UP TO 20 KT ON THE SOUND THIS EVENING BEFORE DISSIPATING AS A
WEAK NORTHERLY FLOW DEVELOPS OVERNIGHT. ON FRIDAY, S-SW WINDS ON
THE OCEAN WATERS IN THE AFTERNOON WILL PUSH 15 TO 20 KT AND
THEN WEAKEN FRIDAY NIGHT. A BRIEF PERIOD OF 5 FT SEAS LATE IN
THE DAY IS POSSIBLE. CONFIDENCE IS LOW AT THIS TIME.
THEREAFTER, A WEAK PRESSURE GRADIENT IN THE LONG TERM WILL MEAN
WINDS REMAIN BELOW SCA CRITERIA. SOUTHERLY FLOW WILL ALLOW
WAVES ON THE OCEAN TO BUILD TO 5 FT SUNDAY NIGHT THROUGH
TUESDAY, MAINLY FOR THE CENTRAL AND EASTERN OCEAN ZONE.
HYDROLOGY
VERY LOCALIZED RAINFALL AMOUNTS UP TO AN INCH ARE POSSIBLE THIS
EVENING, MAINLY ACROSS THE NYC METRO AND WESTERN LONG ISLAND
EARLY THIS EVENING. THIS COULD RESULT IN POOR DRAINAGE AND LOW
LYING FLOODING.
NO HYDROLOGIC IMPACTS ARE EXPECTED FRIDAY INTO NEXT WEEK.
CLIMATE
THE FOLLOWING ARE RECORDS FOR THIS WEEKEND:
RECORD HIGHEST MINIMUM TEMPERATURES FOR SATURDAY, JULY 20:
NYC: 82 IN 2015
LGA: 83 IN 2015
JFK: 79 IN 2015
EWR: 80 IN 2015
ISP: 78 IN 2013
BDR: 79 IN 2013
RECORD HIGH TEMPERATURES FOR SATURDAY, JULY 20:
NYC: 101 IN 1980
LGA: 101 IN 1991
JFK: 96 IN 2013 (ALSO OCCURRED IN PREVIOUS YEARS)
EWR: 101 IN 1980
ISP: 97 IN 1991
BDR: 95 IN 1001
RECORD HIGHEST MINIMUM TEMPERATURES FOR SUNDAY, JULY 21:
NYC: 82 IN 1980
LGA: 83 IN 1980
JFK: 79 IN 2017
EWR: 81 IN 1980
ISP: 76 IN 1980
BDR: 76 IN 1994
RECORD HIGH TEMPERATURES FOR SUNDAY, JULY 21:
NYC: 104 IN 1977
LGA: 100 IN 1991
JFK: 99 IN 1991
EWR: 103 IN 2011
ISP: 101 IN 1991
BDR: 98 IN 1991
EQUIPMENT
NYC NOAA WEATHER RADIO STATION KWO35 (162.55 MHZ) REMAINS OFF
THE AIR.
OKX WATCHES/WARNINGS/ADVISORIES
CT...EXCESSIVE HEAT WARNING FROM 6 AM SATURDAY TO 8 PM EDT SUNDAY
FOR CTZ005>012.
HEAT ADVISORY FROM NOON FRIDAY TO 6 AM EDT SATURDAY FOR
CTZ005>012.
NY...EXCESSIVE HEAT WARNING FROM 6 AM SATURDAY TO 8 PM EDT SUNDAY
FOR NYZ078>081-177-179.
HEAT ADVISORY FROM NOON FRIDAY TO 6 AM EDT SATURDAY FOR
NYZ078>081-177-179.
EXCESSIVE HEAT WARNING FROM NOON FRIDAY TO 8 PM EDT SUNDAY FOR
NYZ067>075-176-178.
NJ...EXCESSIVE HEAT WARNING FROM NOON FRIDAY TO 8 PM EDT SUNDAY FOR
NJZ002-004-006-103>108.
MARINE...NONE.
SYNOPSIS...JP/DW
NEAR TERM...DW
SHORT TERM...DW
LONG TERM...JP
AVIATION...IRD
MARINE...JP/DW
HYDROLOGY...JP/DW
CLIMATE...//
EQUIPMENT...//
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