Area Forecast Discussion
Issued by NWS Upton, NY

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000
FXUS61 KOKX 220548
AFDOKX

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE NEW YORK NY
1248 AM EST MON DEC 22 2014

.SYNOPSIS...
HIGH PRESSURE REMAINS NORTHEAST THROUGH TONIGHT 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 EARLY THIS
MORNING...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. SO EVEN IF MOISTURE IS DEEP ENOUGH TO SUPPORT SNOW
PRODUCING PROCESSES...ANY PRECIP MAY CHANGE OVER THE RAIN ANYWAY.

CLOUDS LIKELY LINGER EARLY THIS MORNING...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/...
HIGH PRESSURE CONTINUES TO RIDGE DOWN FROM SOUTHEASTERN
CANADA...AS A TROUGH OF LOW PRESSURE LINGERS NEAR THE AREA INTO
TONIGHT.

THE FEW POCKETS OF VFR THAT EXIST THIS MORNING SHOULD GIVEWAY TO
MVFR BY 8Z...WITH WIDESPREAD MVFR CONDITIONS CONTINUING THROUGH
DAY...WITH POCKETS OF IFR AT TIMES. LOW CONFIDENCE ON TIMING/
EXACT LOCATION OF ANY IFR CONDITIONS DURING THE DAY. BETTER CHANCE
OF IFR LATE THIS AFTERNOON/EVENING.

POCKETS OF LIGHT RAIN/DRIZZLE/SNOW WILL REMAIN EARLY THIS MORNING
DUE TO THE AFOREMENTIONED TROUGH...MOSTLY EAST OF THE NYC
TERMINALS. ISOLD-SCT SHOWERS MOVE IN THIS AFTERNOON/EVENING.

A WEAK N-NNE FLOW AT LESS THAN 10 KT GRADUALLY VEERS AROUND TO
NE-E BY THIS AFTERNOON.

.OUTLOOK FOR 06Z MONDAY THROUGH FRIDAY...
.LAE TONIGHT...IFR LIKELY.
.TUESDAY-TUESDAY NIGHT...IFR LIKELY. E WINDS G15-20 KT PROBABLE...
BECOMING SE.
.WEDNESDAY-WEDNESDAY NIGHT...HIGH IMPACT EVENT BECOMING LIKELY. IFR
WITH +RA. S/SE WINDS 15-20G20-25KT POSSIBLE. LLWS POSSIBLE
EASTERN AND MAYBE SOUTHERN TERMINALS. WINDS SHIFT TO THE SW LATE
AT NIGHT.
.THURSDAY-THURSDAY NIGHT...VFR CONDITIONS RETURN BY AFTERNOON.
-SHRA IN THE MORNING. W WINDS 15-20G25-35KT LIKELY.
.FRIDAY...VFR. W-NW WINDS G20KT POSSIBLE.

&&

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

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

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
SHORT TERM...PW
LONG TERM...MET
AVIATION...MALOIT/24
MARINE...MET/PW
HYDROLOGY...MET/PW








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