Area Forecast Discussion
Issued by NWS Upton, NY

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000
FXUS61 KOKX 050327
AFDOKX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW YORK NY
1127 PM EDT TUE AUG 4 2015

.SYNOPSIS...
A COLD FRONT WILL SLOWLY PASS THROUGH THE REGION OVERNIGHT...PUSHING
OFFSHORE EARLY WEDNESDAY. WEAK HIGH PRESSURE BUILDS INTO THE AREA
ON THURSDAY. LOW PRESSURE MAY IMPACT THE AREA FRIDAY INTO
SATURDAY. HIGH PRESSURE RETURNS FOR THE SECOND HALF OF THE
WEEKEND. A FRONTAL SYSTEM APPROACHES AND AFFECTS THE AREA FOR THE
BEGINNING OF NEXT WEEK.

&&

.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
FORECAST ON TRACK WITH JUST MINOR ADJUSTMENTS TO REFLECT LATEST
OBSERVATIONS. OTHERWISE...A COLD FRONT WAS MOVING INTO THE
AREA...BRINGING IN MUCH DRIER AIR WITH DEW POINTS FALLING INTO THE
LOWER 50S AND UPPER 40S. WITH THE FRONT EXPECTED TO BE ACROSS THE
EASTERN FORECAST AREA BY 05Z AND WITH THE AREA BECOMING STABLE
THIS EVENING...HAVE REMOVED POPS.

&&

.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT/...
UPR JET DIVES INTO THE AREA BY AFTN. DESPITE LIMITED INSTABILITY...
THE 12Z NAM WAS PICKING UP ON SCT-ISOLD CONVECTION INTO THE EARLY
EVE. THE 12Z GFS WAS DRY. LAPSE RATES ARE SLIGHTLY STEEPER IN THE
NAM...WITH AROUND 8C BETWEEN H85-H7. THE GFS IS AROUND 7C IN THE
SAME LAYER. WITH THE APPROACHING COLD POOL ALOFT...JET AND WARM
SST/S...DID NOT DISCOUNT THE NAM AND HAVE THEREFORE INCLUDED 20
POPS FOR DIURNAL ACTIVITY. ISOLD LIGHTNING STRIKES TODAY INVOF
LAKES HURON AND ONTARIO LEND SOME SUPPORT TO TSTM CHCS. TEMPS A
BLEND OF THE GUIDANCE WHICH WAS IN GOOD AGREEMENT.

THERE IS A MODERATE RISK FOR RIP CURRENTS AT THE OCEAN BEACHES
WEDNESDAY.

&&

.LONG TERM /THURSDAY THROUGH TUESDAY/...
UPPER LEVEL LOW OVER SOUTHEASTERN CANADA WILL PUSH EAST ON
THURSDAY...ALLOWING FOR ZONAL FLOW TO DEVELOP ALOFT. SURFACE HIGH
PRESSURE BUILDS IN AT THE SURFACE KEEPING THE AREA DRY.

COMPLICATED FORECAST THEREAFTER IN REGARDS TO THE POTENTIAL FOR LOW
PRESSURE IMPACTING THE AREA MAINLY FROM LATE THURSDAY NIGHT THROUGH
AT LEAST SATURDAY. THIS STORM WILL FORM FROM A SHORTWAVE CURRENTLY
OVER THE ROCKIES WHICH WILL EJECT OUT INTO THE MID-WEST WEDNESDAY
NIGHT INTO THURSDAY MORNING. THIS WILL ALLOW A WEAK SURFACE LOW TO
DEVELOP. THE TRACK OF THIS LOW THEREAFTER IS VERY UNCERTAIN. 12Z NAM
AND THE 00Z ECMWF SHARE A SIMILAR TRACK...BRINGING THE LOW OVER THE
OHIO VALLEY OVERNIGHT THURSDAY...OVER THE MID-ATLANTIC ON FRIDAY AND
OFF THE EAST COAST FRIDAY NIGHT INTO SATURDAY MORNING.
THEREAFTER...THE ECMWF PASSES SOUTH AND EAST LONG ISLAND SATURDAY.
THE 12Z GFS AND THE CANADIAN TAKE THE LOW OVER FARTHER SOUTH...OVER
VIRGINIA/NORTH CAROLINA...THEN TURNING NORTHEAST AND PASSING WELL
SOUTH AND EAST OF THE AREA...HUNDREDS OF MILES EAST OF THE 40/70
BENCHMARK...AND THUS HAVING NO IMPACT TO THE AREA WHATSOEVER. THE
00Z ECMWF ENSEMBLE MEAN FOLLOWS A SIMILAR TRACK TO THE
OPERATIONAL...BUT THERE IS A GOOD DEAL OF SPREAD AND THUS
UNCERTAINTY WITH THE LOW AS IT EJECTS OUT OF THE ROCKIES.
THEREFORE...EXPECT A GOOD DEAL OF DIFFERENCES IN MODELS SOLUTIONS
UNTIL THIS FEATURE MOVES OUT OF THE ROCKIES. GIVEN THE
UNCERTAINTY...WILL NOT MAKE MUCH IN THE WAY OF CHANGES WITH WHAT IS
CURRENTLY IN THE FORECAST.

ANOTHER CONCERN IS THE NEW 12Z ECMWF HAS SHIFTED FARTHER SOUTH THAN
THE PREVIOUS RUN...COMING MORE IN LINE WITH THE GFS AND
CANADIAN...MAKING THE NAM MORE OF AN OUTLIER. IF THIS TREND
CONTINUES WITH THE MODELS...THERE WOULD BE MUCH LESS IN THE WAY OF
RAINFALL.

&&

.AVIATION /04Z WEDNESDAY THROUGH SUNDAY/...
VFR AS A COLD FRONT PASSES TO THE EAST OVERNIGHT...FOLLOWED BY
HIGH PRESSURE ON WEDNESDAY.

W WINDS 5-10 KT SHOULD VEER MORE NW OVERNIGHT...AND BECOME LIGHT
OUTSIDE THE NYC METRO. W WINDS SHOULD PICK UP AGAIN BY AFTERNOON
10-15 KT WITH GUSTS 15-20 KT...WITH SW SEA BREEZE ONLY AT KGON.

.OUTLOOK FOR 00Z THU THROUGH SUNDAY...
.WED NIGHT...VFR WITH W WINDS DIMINISHING AND SHIFTING NW.
.FRI-SAT...CHANCE OF MVFR OR LOWER CONDS IN RAIN.
WINDS BECOMING NE.
.SUNDAY...VFR.

&&

.MARINE...
FORECAST WINDS AND SEAS ON TRACK WITH NO CHANGES AT THIS TIME.

SEAS STILL IN THE 4-7 FT RANGE ON THE OCEAN...AND A SMALL CRAFT
ADVISORY REMAINS IN EFFECT THROUGH TONIGHT. WINDS AND SEAS
SUBSIDE TO BLW SCA LVLS ALL WATERS WED AND WED NGT.

WEAK HIGH PRESSURE WILL MOVE OVER THE WATERS ON THURSDAY WITH LOW
PRESSURE ON FRIDAY INTO SATURDAY. SUB SCA CONDITIONS ARE EXPECTED
THURSDAY INTO FRIDAY...WITH SEAS BUILDING TO AROUND 5 FT ON THE
OCEAN SATURDAY INTO SATURDAY NIGHT WITH THE APPROACH OF THE LOW.
SEAS SUBSIDE SUNDAY AS THE LOW PUSHES AWAY FROM THE AREA.

&&

.HYDROLOGY...
ORGANIZED SIGNIFICANT RAINFALL IS NOT EXPECTED THROUGH THURSDAY.

A WIDESPREAD SIGNIFICANT RAINFALL IS POSSIBLE LATE THURSDAY INTO
FRIDAY. HOWEVER...UNCERTAINTY EXISTS IN WHERE AND WHEN THE HEAVIEST
OF THE RAIN WILL FALL. ANTECEDENT DRY CONDITIONS SHOULD LIMIT
FLOODING POTENTIAL. HOWEVER...ANY HEAVIER RAINFALL THAT DOES DEVELOP
WOULD HAVE THE POTENTIAL FOR LOCALIZED FLOODING.

&&

.EQUIPMENT...
TEWR TERMINAL DOPPLER RADAR REMAINS UNAVAILABLE.

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
NJ...NONE.
MARINE...SMALL CRAFT ADVISORY UNTIL 6 AM EDT WEDNESDAY FOR ANZ350-353-
     355.

&&

$$
SYNOPSIS...JMC/JP
NEAR TERM...BC/MET
SHORT TERM...JMC
LONG TERM...JP
AVIATION...GOODMAN
MARINE...MET
HYDROLOGY...JMC/JP
EQUIPMENT...


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