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Area Forecast Discussion
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000
FXUS61 KOKX 220457
AFDOKX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW YORK NY
1157 PM EST SUN DEC 21 2014

.SYNOPSIS...
HIGH PRESSURE REMAINS NORTHEAST THROUGH MONDAY NIGHT AS LOW
PRESSURE APPROACHES FROM THE SOUTH. HIGH PRESSURE REMAINS
NORTHEAST THROUGH MONDAY NIGHT AS LOW PRESSURE APPROACHES FROM THE
SOUTH. THE WAVE OF LOW PRESSURE WEAKENS WHILE MOVING NORTH TUESDAY
AND TUESDAY NIGHT. A MORE SIGNIFICANT STORM SYSTEM AFFECTS THE
AREA TUESDAY NIGHT THROUGH EARLY CHRISTMAS DAY WITH A COLD FRONT
PASSING THROUGH LATE WEDNESDAY NIGHT INTO THURSDAY MORNING. HIGH
PRESSURE BUILDS IN LATE THURSDAY THROUGH FRIDAY. A WEAK COLD FRONT
MOVES THROUGH DRY SATURDAY. ANOTHER LOW APPROACHES FROM THE SOUTH
SUNDAY.

&&

.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
AREA OF LIGHT RAIN OVER LONG ISLAND BEGINNING TO MOVE TO THE
NORTH...AND EVEN SPREADING TO THE WEST A BIT. ANY RAIN SHOWERS
WILL BE LIGHT...AND WITH PRECIP MOVING INTO AREA OF COLDER
AIR...RAIN MAY MIX WITH SNOW. GOING THROUGH THE OVERNIGHT...WITH
TEMPS SLOWLY FALLING...ANY PRECIP MAY FREEZE ON THE ROAD SURFACES. 

OTHERWISE...IF MOISTURE IS DEEP ENOUGH TO SUPPORT SNOW...VERY
LIGHT SNOW OR FLURRIES WILL BE THE RESULT.

HOWEVER...COMPLICATING THINGS IS THAT TEMPS THROUGH 850 HPA OR SO 
WARM SLIGHTLY AS THE NIGHT PROGRESSES. SO EVEN IF MOISTURE IS DEEP 
ENOUGH TO SUPPORT SNOW PRODUCING PROCESSES...ANY PRECIP MAY
CHANGE OVER THE RAIN ANYWAY AS THE NIGHT WEARS ON.

CLOUDS LIKELY LINGER THROUGH THE NIGHT...BUT THESE LOW CLOUDS
COULD BREAK UP SOMEWHAT AS RIDGE BUILDS.

TEMPS ARE A BLEND OF LATEST MOS AND FORECAST DATABASE.

&&

.SHORT TERM /6 AM MONDAY MORNING THROUGH MONDAY NIGHT/...
UPPER RIDGE BUILDS AHEAD OF DIGGING MID WEST TROUGH. HIGH PRESSURE 
REMAINS ANCHORED OVER THE CANADIAN MARITIMES THROUGH MONDAY NIGHT.

A WEAK AREA OF LOW PRESSURE DEVELOPS ALONG A WARM FRONT OFF THE MID 
ATLANTIC...DRIFTING NORTHWARD TOWARD THE AREA.

WEAK LOW LEVEL LIFT WILL RESULT IN CHANCE POPS FOR LIGHT RAIN 
THROUGH THE PERIOD. DO NOT EXPECT REAL HIGH COVERAGE AT THIS TIME. 

TEMPS WARM INTO THE MIDDLE 30S MONDAY ACROSS THE INTERIOR...WITH 
LOWER TO MIDDLE 40S EXPECTED NEAR THE COAST. THESE TEMPS LIKELY 
REMAIN STEADY MONDAY NIGHT DUE TO EAST FLOW AND CLOUDY SKIES.

&&

.LONG TERM /TUESDAY THROUGH SUNDAY/...
WEAK LOW TO THE SOUTH CONTINUES TO WEAKEN TUESDAY AS A WARM FRONT 
DEVELOPS ASSOCIATED WITH A DEEPENING LOW OVER THE MIDWEST AND LOWER 
MISSISSIPPI RIVER VALLEY. ALL GUIDANCE DOES NOT MAINTAIN A CLOSED 
CIRCULATION AS PREVIOUSLY FORECAST. OTHERWISE THERE IS GENERALLY 
CONSISTENCY WITH THE MIDWESTERN LOW DEEPENING AND TRACKING NORTHWARD 
TUESDAY NIGHT THROUGH THURSDAY MORNING AS THE FULL LATITUDE UPPER 
TROUGH BECOMES NEGATIVELY TILTED. ONLY CHANGE HAS BEEN A SLIGHTLY 
SLOWER COLD FRONTAL PASSAGE ACROSS THE REGION. CURRENTLY FORECAST TO 
COME THROUGH JUST AFTER 06Z THURSDAY...AND CLEAR THE EASTERN ZONES 
JUST AFTER 12Z CHRISTMAS DAY. ALSO...BOTH THE GFS AND ECMWF PROFILES 
ARE SLIGHTLY WARMER THAN YESTERDAY AND ALL RAIN IS EXPECTED FOR THE 
EVENT.

WITH A STRONG LOW LEVEL JET LATE WEDNESDAY INTO WEDNESDAY NIGHT AND 
STRONG LIFT PERIODS OF HEAVY RAINFALL CAN BE EXPECTED. ALSO THERE 
WILL BE A DEEP INFLUX OF GULF OF MEXICO AND ATLANTIC MOISTURE AHEAD 
OF THE TROUGH. UP TO 2 INCHES WILL LOCALLY HIGHER AMOUNTS WILL BE 
POSSIBLE. SEE HYDROLOGY SECTION.

IN THE COLDER AIR BEHIND THE FRONT THURSDAY WINDS AND GUSTS INCREASE 
BUT ARE EXPECTED TO REMAIN BELOW ADVISORY LEVELS.

HIGH PRESSURE BUILDS IN FOR FRIDAY. THEN A WEAK COLD FRONT CROSSES 
THE REGION SATURDAY...HOWEVER THE PASSAGE IS EXPECTED TO NOW BE DRY. 
A WAVE OF LOW PRESSURE DEVELOPS ON THE FRONT ACROSS THE GULF COAST 
STATES LATER SATURDAY AND TRACKS NORTH SUNDAY BRINGING THE NEXT 
CHANCE OF PRECIPITATION. THE STORM WILL BE INLAND AND THE AREA WILL 
BE ON THE WARM SIDE WITH ALL LIQUID PRECIPITATION EXPECTED.

&&

.AVIATION /06Z MONDAY THROUGH FRIDAY/...
WEAK SURFACE TROUGH ACROSS THE AREA AND LOW-LEVEL MOISTURE TRAPPED 
BENEATH AN INVERSION WILL RESULT IN WIDESPREAD MVFR CONDITIONS 
THROUGH MON...WITH EVEN SOME LOCATIONS BEING IFR. HOWEVER...THERE
IS LOW CONFIDENCE IN THE TIMING OF CONDS DROPPING TO IFR.

POCKETS OF LIGHT RAIN/DRIZZLE/SNOW WILL POSSIBLE INTO THE
OVERNIGHT HOURS DUE TO THE AFOREMENTIONED TROF...MOSTLY EAST OF
THE NYC TERMINALS.

A WEAK NLY FLOW AT LESS THAN 10 KT GRADUALLY VEERS AROUND TO E/NE
BY MON AFT.

.OUTLOOK FOR 00Z MONDAY THROUGH FRIDAY...
.MON NIGHT...IFR POSSIBLE IN E FLOW AND RAIN.
.TUE-TUE NIGHT...IFR LIKELY IN RAIN. E WINDS 10-20 KT...BECOMING
SE.
.WED...HIGH IMPACT EVENT BECMG LIKELY. IFR WITH +RA. S/SE WINDS
15-20G20-25KT. WINDS SHIFT TO THE SW LATE WED NIGHT.
.THU...VFR CONDS RETURNING BY AFTN. -SHRA IN THE MORNING. W WINDS
15-20G25-35KT.
.FRI...VFR.

&&

.MARINE...
LIGHT NORTHERLY WINDS CONTINUE TONIGHT...SLOWLY SHIFTING EAST AS 
HIGH PRESSURE REMAINS WELL NORTHEAST OF THE WATERS. A WEAK AREA OF 
LOW PRESSURE DEVELOPS OFF THE MID ATLC COAST AND DRIFTS NORTHWARD 
TOWARD THE WATERS MONDAY AND MONDAY NIGHT. EAST WINDS INCREASE 
SLIGHTLY BUT SHOULD REMAIN BELOW SCA THRESHOLDS.

SEAS REMAIN 4 FT OR LESS OVER THE OCEAN WATERS THROUGH MONDAY NIGHT.

A PERSISTENT EASTERLY FLOW INTO TUESDAY WILL ALLOW FOR SEAS ON THE 
OCEAN WATERS TO BUILD TO SMALL CRAFT LEVELS AHEAD OF AN APPROACHING 
WARM FRONT. WIND AND GUSTS ARE EXPECTED TO REMAIN BELOW ADVISORY 
LEVELS TUESDAY INTO TUESDAY NIGHT.

A DEEPENING LOW PRESSURE SYSTEM OVER THE MIDWEST WEDNESDAY WILL 
RESULT IN AN INCREASING SOUTHERLY FLOW AND WIND AND GUSTS WILL 
INCREASE TO SMALL CRAFT LEVELS ACROSS ALL THE WATERS BY LATE 
WEDNESDAY. THEN WEDNESDAY NIGHT THE WIND GUSTS ON THE OCEAN INCREASE 
TO GALE FORCE.

A COLD FRONT ASSOCIATED WITH THE LOW PASSES THROUGH THE WATERS LATE 
WEDNESDAY NIGHT INTO EARLY THURSDAY MORNING. SOUTHERLY WIND SHIFTS 
TO THE WEST TO NORTHWEST AND BECOMES VERY GUSTY IN THE COLDER AIR. 
GALE FORCE GUSTS WILL BECOME LIKELY ACROSS ALL THE WATERS DURING 
THURSDAY AND THEN SUBSIDE TO BELOW GALE FORCE THURSDAY NIGHT...AND 
POSSIBLY BELOW SMALL CRAFT DURING FRIDAY AS HIGH PRESSURE BUILDS 
IN.

A WEAK COLD FRONT COMES THROUGH DRY SATURDAY...AND WIND AND SEA ARE 
LIKELY TO BE BELOW SMALL CRAFT LEVEL.

&&

.HYDROLOGY...
NO SIGNIFICANT PRECIPITATION IS EXPECTED THROUGH MONDAY...MAINLY 
JUST LIGHT AMOUNTS.

RAINFALL FROM MONDAY AFTERNOON THROUGH THURSDAY MORNING COULD TOTAL 
1 1/2 TO 2 INCHES WITH LOCALLY HIGHER AMOUNTS. MUCH OF THE RAINFALL 
IS EXPECTED TO OCCUR WEDNESDAY INTO WEDNESDAY NIGHT. MINOR URBAN AND 
POOR DRAINAGE FLOODING IS POSSIBLE.

DRY WEATHER RETURNS THURSDAY AFTERNOON THROUGH SATURDAY NIGHT.

&&

.OKX WATCHES/WARNINGS/ADVISORIES...
CT...NONE.
NY...NONE.
NJ...NONE.
MARINE...NONE.

&&

$$
SYNOPSIS...MET/PW
NEAR TERM...JP/MPS
SHORT TERM...PW
LONG TERM...MET
AVIATION...
MARINE...MET/PW
HYDROLOGY...MET/PW









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