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-- Discussion containing changed information from previous version are highlighted. --
000
FXUS61 KOKX 272043
AFDOKX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW YORK NY
443 PM EDT SUN JUL 27 2014

.SYNOPSIS...
A STRENGTHENING LOW PRESSURE SYSTEM WILL APPROACH THE REGION
TONIGHT AND THEN TRACK THROUGH NEW ENGLAND ON MONDAY AS THE COLD
FRONT MOVES ACROSS THE LOCAL AREA. COLD FRONT PUSHES EAST MONDAY
NIGHT...SETTLING WELL OFFSHORE THROUGH THE MIDDLE OF THE WEEK AS
HIGH PRESSURE BUILDS IN THE WAKE. LOW PRESSURE APPROACHES AGAIN
FOR NEXT WEEKEND.

&&

.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
CONVECTIVE COVERAGE THROUGH THE EVENING WILL BE QUITE ISOLATED
DESPITE MARGINAL TO MODERATE INSTABILITY...DUE TO WEAK SUBSIDENCE
AND EVEN A BIT OF MID- LEVEL CAPPING IN WAKE OF EARLIER SHORTWAVE.
ANYTHING THAT DOES DEVELOPS HAS POTENTIAL TO BE STRONG TO
SEVERE...WITH SHEAR/INSTABILITY LEVELS SUPPORTIVE...BUT AGAIN AN
ISOLATED THREAT.

MAIN CONCERN IS FOR TONIGHT AS A STRONG JET STREAK/POTENT SHORTWAVE
AND STRENGTHENING SFC LOW/PRE-FRONTAL TROUGH APPROACHING
TONIGHT...WITH ANOTHER ROUND OF SHRA/TSTMS EXPECTED OVERNIGHT. THE
STRONG FORCING AND A MODERATE DEEP/LOW LEVEL SHEAR ENVIRONMENT ARE
FAVORABLE FOR SEVERE WEATHER INTO THE OVERNIGHT...BUT THE LIMITING
FACTOR WILL BE AMOUNT OF INSTABILITY REMAINING OVERNIGHT. AT LEAST
ELEVATED MARGINAL INSTABILITY IS EXPECTED OVERNIGHT...BUT WITH
UNSEASONABLY STRONG LLJ THIS COULD APPROACH/REMAIN NEAR MODERATE
LEVELS. LOW/CAPE HIGH SHEAR ENVIRONMENTS ARE USUALLY NOT FAVORABLE
FOR WIDESPREAD SEVERE WEATHER COVERAGE...BUT WITH STRONG FORCING
AND IF LLJ CAN MAINTAIN HIGHER INSTABILITY A MORE WIDESPREAD
SEVERE EVENT IS POSSIBLE.

THE MAIN FOCUS FOR CONVECTION AFFECTING OUR AREA TONIGHT WILL BE
ALONG AN APPROACHING PRE-FRONTAL TROUGH. WOULD EXPECT AT LEAST
SCATTERED COVERAGE OF STORMS OR LINE SEGMENTS ALONG THIS
BOUNDARY...BUT IF INSTABILITY REMAINS HIGHER...COVERAGE WOULD
INCREASE AND COULD TAKE THE FORM OF A QLCS. MAIN THREAT WITH ANY
LINE SEGMENT OR QLCS WILL BE DAMAGING WINDS AND HEAVY RAIN...WITH
SUFFICIENT LOW-LEVEL SHEAR/HELICITY FOR STORM ROTATION AND A LOW
PROB OF A TORNADO. DISCRETE CELLS HAVE POTENTIAL TO ROTATE AND
PRODUCE LARGE HAIL AS WELL...BUT LOW CAPE/HIGH SHEAR ENVIRONMENTS
ARE NOT FAVORABLE FOR HAIL...SO THIS IS A LOW THREAT.

SO LOOKING FOR COVERAGE TO INCREASE SLIGHTLY THIS EVENING FROM NYC
METRO AND POINTS N&W AS BETTER JET/SHORTWAVE ENERGY APPROACH...BUT
MAIN ACTIVITY WITH PRE-FRONTAL TROUGH LIKELY OCCURS AFTER MIDNIGHT
FROM NYC METRO AND POINTS WEST...AND AFTER 2-3 AM INTO LI/CT.

AS THE LOW TRACKS INTO SOUTHERN NEW ENGLAND LATE TONIGHT INTO
EARLY MONDAY MORNING...THE PRE-FRONTAL TROUGH WILL LIFT NE WITH
BEST FORCING/MOISTURE/INSTABILITY LIFTING N AND E...BRINGING AN
END TO THE WIDESPREAD SHRA/TSRA AND SVR THREAT.

THERE IS A MODERATE RISK FOR THE DEVELOPMENT OF RIP CURRENTS ALONG
THE ATLANTIC OCEAN FACING BEACHES INTO THIS EVENING.

&&

.SHORT TERM /6 AM MONDAY MORNING THROUGH 6 PM MONDAY/...
-- Changed Discussion --
SURFACE LOW TRACKS THROUGH NEW ENGLAND ON MONDAY...WITH PRE-FRONTAL
TROUGH MOVING NORTH AND RELATIVELY DRIER AIRMASS ADVECTING IN.

BREEZY AND SEASONABLY WARM CONDITIONS ARE EXPECTED. CONSIDERABLE
INSTABILITY CLOUD COVER AND DIURNAL SCT-NUM SHRA DEVELOPMENT
LIKELY IN THE AFTERNOON WITH COLD POOL INSTABILITY AND DIURNAL
HEATING...AS WELL AS ALONG AHEAD OF COLD FRONTAL PASSAGE IN
AFT/EVE. GREATEST COVERAGE EXPECTED ACROSS THE INTERIOR OFF HIGHER
TERRAIN. A FEW STRONG TO SEVERE STORMS ARE POSSIBLE...WITH HAZARDS
IN THE FORM OF LARGE HAIL AND GUSTY WINDS.

FRONT SHOULD CLEAR THE AREA MON EVE WITH DRIER AND COOLER AIRMASS
ADVECTING IN.

THERE IS A MODERATE RISK FOR THE DEVELOPMENT OF RIP CURRENTS ALONG
THE ATLANTIC OCEAN FACING BEACHES DURING THE DAY MONDAY.
-- End Changed Discussion --

&&

.LONG TERM /MONDAY NIGHT THROUGH SUNDAY/...
LINGERING CHC FOR PCPN OVER SOUTHERN CT/LOWER HUDSON RIVER VALLEY
FIRST HALF OF MON NIGHT AS SFC LOW LIFTS TO THE NORTH...DRAGGING ITS
ASSOCIATED COLD FRONT THROUGH THE EASTERN HALF OF THE AREA. 12Z
MODEL GUIDANCE GENERALLY AGREEING THE BEST FORCING ALOFT ASSOCIATED
WITH A PASSING VORT MAX SHOULD REMAIN NORTH AND EAST OF THE AREA...BUT
MAY PUSH JUST SOUTH ENOUGH TO ASSIST IN PROLONGING ANY PCPN THAT
DEVELOPED LATE IN THE DAY. BOTH INSTABILITY AND SHEAR ON THE WEAKER
SIDE BY 00Z TUES...SO LOOKING FOR MORE ISO-SCT SHOWERS WITH A LOW
END CHC OF A TSTM. BY 06Z...PCPN SHOULD HAVE CLEARED THE AREA WITH
ANY FORCING AT BOTH THE SFC AND ALOFT NOW EXITING THE AREA. PW
VALUES WILL ALSO HAVE DROPPED BEHIND THE FRONT...SO ANY FLOODING
THREAT WITH THE SHOWERS WILL HAVE DIMINISHED.

UPPER LEVEL TROUGH DIGS SOUTH TUES THROUGH MID WEEK WITH A CLOSED
LOW HOVERING JUST NORTH OF THE GREAT LAKES. WITH MINIMAL
PROGRESSIVE MOVEMENT ALOFT...THE COLD FRONT IS EXPECTED TO PUSH
EAST...BUT THEN STALL OFFSHORE. IT SHOULD PUSH JUST FAR ENOUGH EAST
TO HAVE MINIMAL IMPACT THROUGH THE COMING WEEK...BUT WILL COME BACK
INTO THE PICTURE FOR THE COMING WEEKEND. AS THE SURFACE HIGH
PRESSURE WILL BE BUILDING IN BEHIND THE FRONT AND WILL MAINTAIN HOLD
OF THE REGION THROUGH THURS. SHORTWAVE ROTATING ON THE SOUTHERN EDGE
OF THE TROUGH COULD TRIGGER AN ISO SHOWER/TSTM TUES AFTN OVER FAR
NORTH AND WESTERN EDGES OF THE AREA...BUT WITH A MUCH DRIER AIRMASS
MOVING IN...COULD VERY WELL END UP BEING A DRY DAY. THE NEXT MENTION
OF PCPN COMES THURS AFTN WITH A RETURN FLOW SETTING UP OVER THE
REGION...INJECTING IN A SLIGHTLY MORE MOIST AIRMASS. THE CLOSED LOW
ALOFT FINALLY PUSHES OFF TO THE NORTHEAST...THOUGH A LONGWAVE TROUGH
STILL WILL PERSIST OVER THE EASTERN HALF OF THE US FOR THE END OF
THE WEEK. THE PATTERN STILL BRINGS THROUGH MULTIPLE SHORTWAVES
THURS-FRI...EACH BRINGING A SLIGHT CHC IN TRIGGERING AN ISO SHOWER
OR TSTM.

LOW PRESSURE FORMS ALONG THE STALLED FRONT BY THIS WEEKEND...RIDING
THE FRONT WHILE SLOWLY APPROACHING THE AREA. GENERAL MODEL CONSENSUS
BRINGS THE SFC LOW NEAR THE TRI STATE AREA BY SUN MORNING. ENOUGH
FORCING ALOFT ROUNDING THE BASE OF THE UPPER LEVEL TROUGH SHOULD
COMBINE WITH THE SFC LOW TO PRODUCE SCT SHOWERS AND TSTMS...ESP FOR
LATER SAT THROUGH SUN.

TEMPS REMAIN NEAR STEADY THROUGH THE COMING WEEK...A FEW DEGREES
BELOW NORMAL.

&&

.AVIATION /21Z SUNDAY THROUGH FRIDAY/...
PRE-FRONTAL SURFACE TROUGH WILL REMAIN IN THE VICINITY INTO THIS
EVENING. ANOTHER PRE-FRONTAL TROUGH APPROACHES LATE TONIGHT AND
EXITS TO THE EAST MONDAY MORNING.

VFR INTO THIS EVENING. ISO/SCT SHRA/TSTM POSSIBLE AT ANY GIVEN
TIME...BUT COVERAGE AND PROBABILITY ARE TOO LOW TO MENTION IN TAFS
UNTIL SHORTLY AFTER MIDNIGHT TONIGHT WHEN STORMS BECOME MORE
NUMEROUS. ANY STORM COULD PRODUCE STRONG GUSTY WINDS AND HAIL.

SOUTHERLY WINDS 10 TO 15 KTS CAN BE EXPECTED INTO THIS EVENING.
OCCASIONAL GUSTS 17-20 KT THIS AFTN.

.OUTLOOK FOR 18Z MON THROUGH  FRI...
.MON PM...MAINLY VFR. CHC SHRA/TSTMS. CHC TEMPO SUB-VFR.
.TUE-THUR...VFR.
.FRI...MOSTLY VFR. ISO SHRA/TSTM

&&

.MARINE...
MODERATE SOUTHERLY WINDS CONTINUE OVERNIGHT AHEAD OF LOW PRESSURE
AND ASSOCIATED COLD FRONT. MARGINAL SCA WILL BUILD SLIGHTLY AND
REMAIN IN THE 4 TO 7 FT RANGE TONIGHT INTO MONDAY.

MARGINAL SCA GUSTS EXPECTED MONDAY AFTERNOON ACROSS ALL NEARSHORE
WATERS IN WAKE OF FRONT.

SEAS ON THE OCEAN ARE EXPECTED TO REMAIN ELEVATED...5-7 FT MON
NIGHT THROUGH TUES MORNING. AS THE WINDS SHIFT AROUND TO THE
NW...SEAS WILL BEGIN TO SUBSIDE...WITH SUB-SCA CONDITIONS EXPECTED
BY TUES AFTN. SUB-SCA CONDITIONS ON ALL WATERS THEN THROUGH THE
REMAINDER OF THE WEEK...WITH A POSSIBLE RETURN TO 25 KT GUSTS AND 5
FT SEAS OVER THE WEEKEND DEPENDING ON THE TRACK OF THE LOW.

&&

.HYDROLOGY...
SCATTERED TO NUMEROUS SHOWERS/TSTMS ARE FORECAST TONIGHT INTO
EARLY MONDAY MORNING WITH AN APPROACHING FRONTAL SYSTEM. ANY OF
THESE STORMS HAVE THE POTENTIAL TO PRODUCE HEAVY DOWNPOURS. SOME
UNCERTAINTY STILL EXISTS WITH COVERAGE OF THUNDERSTORMS THOUGH.
MINOR URBAN FLOODING IS POSSIBLE WITH THESE HEAVY DOWNPOURS...BUT
FLASH FLOODING IS NOT EXPECTED SINCE STORMS SHOULD BE MOVING AND
TRAINING IS NOT ANTICIPATED.

SCATTERED CONVECTION IS LIKELY MONDAY AFTERNOON...WITH LOCALIZED
MINOR URBAN FLOOD THREAT.

NO SIGNIFICANT HYDROLOGIC ISSUES ARE EXPECTED TUES THROUGH THE END
OF THE WEEK.

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
NJ...NONE.
MARINE...SMALL CRAFT ADVISORY FROM 11 AM TO 6 PM EDT MONDAY FOR ANZ330-
     335-338-340-345.
     SMALL CRAFT ADVISORY UNTIL 6 PM EDT MONDAY FOR ANZ350-353-355.

&&

$$
SYNOPSIS...SEARS/NV
NEAR TERM...NV
SHORT TERM...NV
LONG TERM...SEARS
AVIATION...JC
MARINE...SEARS/NV
HYDROLOGY...SEARS/NV