Friday, October 5, 2012

New York City area forecast discussion from noaa.gov

Here's the short and long-term forecast discussion for the New York City metro-area from noaa.gov.enjoy:








NATIONAL WEATHER SERVICE NEW YORK NY
1:51AM,EDT SATURDAY OCTOBER 6,2012

.SYNOPSIS...
HIGH PRESSURE GIVES WAY TO A COLD FRONT SATURDAY. THE FRONT SETTLES
JUST TO THE SOUTH AS LOW PRESSURE RIDES ALONG IT SUNDAY. HIGH
PRESSURE BUILDS EARLY NEXT WEEK AS ANOTHER COLD FRONT MOVES THROUGH
BY MID WEEK.

&&

.NEAR TERM /UNTIL 6 AM THIS MORNING/...
FORECAST REMAINS ON TRACK FOR EARLY THIS MORNING.

THE DELAY OF CLOUD COVER WITH A LIGHT SOUTHERLY FLOW ACROSS THE
AREA IS CAUSING VSBYS TO DROP. MAY HAVE SOME PATCHY FOG IN THE
USUAL OUTLYING AREAS AND RIVER VALLEYS FOR A FEW HOURS AS DEWPOINT
DEPRESSIONS DECREASE OVERNIGHT...BUT PRESSURE GRADIENT IS FORECAST
TO TIGHTEN AND SFC WINDS MAY INCREASE JUST ENOUGH TO KEEP VSBYS
FROM DROPPING BELOW 2 MILES. INCREASING CLOUDS WILL ALSO KEEP THE
DEPRESSIONS HIGHER...ESPECIALLY LATE SO ONLY HAVE PATCHY FOG UNTIL
AROUND DAYBREAK.

A WEAK SHORTWAVE TROUGH WILL MOVE QUICKLY TO THE NW LATE TONIGHT
WITH INCREASING CLOUDS AS A SFC COLD FRONT NEARS FAR NW
ZONES. A MILD NIGHT WITH ABOVE NORMAL TEMPS IS EXPECTED DUE TO THE
INCREASE IN CLOUD COVER AND A RETURN FLOW. MOS GUIDANCE WAS IN
GOOD AGREEMENT WITH LOWS TONIGHT AND A BLEND WAS USED AS A RESULT.

&&

.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM SUNDAY/...
AT THE SFC...COLD FRONT MOVES EAST ACROSS THE AREA SATURDAY AND
SETTLES TO THE SOUTH. LOW PRESSURE DEVELOPS ON THIS FRONT AND
REMAINS WELL SOUTH SUNDAY AS SFC RIDGING BUILDS TO THE WEST.

IN THE UPPER LEVELS...LARGE GENERAL TROUGH...WITH SHORTWAVE PIVOTING
AROUND THE BASE...IMPACTS MUCH OF THE NORTHEAST.

DID NOT MAKE WHOLESALE CHANGES TO THE DATABASE FOR THIS
WEEKEND...ESPECIALLY WITH REGARD TO PRECIPITATION PROBABILITIES DUE
TO MIXED MODEL SIGNALS.

CLOSE ANALYSIS OF SREF ENS MEMBERS...ALONG WITH OPERATIONAL
GFS/NAM/00Z ECMWF...SUGGEST MAINTAINING CHANCE POPS FOR SATURDAY
ALONG THE COLD FRONT...AND LIKELY POPS SUNDAY. MANY SREF MEMBERS
WERE ACTUALLY FAIRLY DRY AND WOULD NOT WARRANT MUCH MORE THAN CHANCE
POPS ON SUNDAY...WHEREAS MANY MODEL SOLUTIONS SUGGEST CATEGORICAL
POPS WITH THIS EVENT.

THIS IS ALL RELATED TO UPSTREAM VIGOROUS SHORTWAVE THAT ROUNDS THE
BASE OF THE MAIN TROUGH...AS IT MOVES FROM SOUTHWEST TO NORTHEAST
SUNDAY. THIS MID AND UPPER LEVEL LIFT SHOULD RESULT IN RAIN
DEVELOPMENT...WHICH WOULD OCCUR WELL TO THE NORTH OF THE FRONTAL
BOUNDARY/LOW PRESSURE. AS SUCH...EXPECT LIKELY POPS IN RAIN BY
SUNDAY AFTERNOON. STAY TUNED.

AS FOR TEMPS...ANOTHER MILD DAY IS IN STORE FOR THE AREA SATURDAY.
AS THE FRONT CLEARS THE AREA...TEMPS SHOULD FALL BACK CLOSER TO
NORMAL LEVELS SATURDAY NIGHT. ON SUNDAY...CLOUDS AND RAIN ALONG WITH
COLD AIR ADVECTION WILL ENSURE BELOW NORMAL TEMPS...IN THE 50S.
AGAIN...FOLLOWED MOS CLOSELY THIS TIME FRAME.

&&

.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
CONDITIONS BEGIN TO IMPROVE FROM WEST TO EAST AS RAIN BEGINS TO
TAPER OFF SUNDAY NIGHT INTO EARLY MONDAY. HIGH PRESSURE BUILDS
ACROSS THE AREA MONDAY AND TUESDAY...BRINGING DRY AND COOL WEATHER.
DAYTIME HIGHS SHOULD BE IN THE UPPER 50S TO LOWER
60S...WITH NIGHT TIME TEMPERATURES IN THE LOW TO MID 40S ALONG COASTAL
AREAS TO MID 30S TO AROUND 40 INLAND.

ANOTHER LOW PRESSURE SYSTEM AND ITS ASSOCIATED COLD FRONT IS
FORECAST TO IMPACT THE AREA ON WEDNESDAY...BRINGING ANOTHER CHANCE
OF RAIN AND MORE COOL AIR BEHIND THE FRONT. HIGH PRESSURE BUILDS
BACK ON THURSDAY WITH ANOTHER FRONTAL SYSTEM EXPECTED ON FRIDAY.

&&

.AVIATION /06Z SATURDAY THROUGH WEDNESDAY/...
HIGH PRESSURE REMAINS OFF THE NORTHEAST COAST OVERNIGHT. A COLD
FRONT WILL APPROACH IN THE MORNING AND MOVE THROUGH THE TERMINALS
DURING THE AFTERNOON. HIGH PRESSURE THEN BUILDS FROM THE WEST
SATURDAY NIGHT.

MAINLY VFR THROUGH THE PERIOD. MVFR FOG AT KGON WILL IMPROVE TOWARD
MORNING.

LIGHT SW FLOW OVERNIGHT INCREASES AND BECOMES GUSTY IN THE MORNING
WITH WINDS INCREASING TO 10 KT  TO 14 KT...WITH SOME GUSTS AS HIGH
AS 24 KT. HIGHEST GUSTS ARE EXPECTED IN THE MORNING TO AROUND
MIDDAY. WINDS BECOME MORE WESTERLY WITH THE APPROACH OF THE COLD
FRONT AND SHIFT TO THE NORTHWEST WITH THE PASSAGE. THERE MAY BE A
COUPLE OF HOURS WHERE THE WIND IN AROUND 310 TRUE WITH THE FRONT IN
THE VICINITY.

SHOWERS WILL BE BRIEF WITH...AND JUST BEHIND THE FRONT...CEILINGS
LOWER TO AROUND 4K FT WITH NO IMPACT TO VISIBILITIES.

OUTLOOK FOR 06Z SUNDAY THROUGH WEDNESDAY...
.SATURDAY NIGHT...VFR.
.SUNDAY...MVFR OR LOWER CONDS POSSIBLE IN RAIN...ESPECIALLY IN THE
AFTERNOON AND EVENING.
.MONDAY-WEDNESDAY...VFR.

&&

.MARINE...
FORECAST REMAINS ON TRACK. SOUTHWEST WINDS AHEAD OF AN APPROACHING
COLD FRONT TONIGHT WILL GRADUALLY INCREASE. IN FACT...WINDS COULD
APPROACH SMALL CRAFT CRITERIA SATURDAY INTO SATURDAY NIGHT...BOTH
AHEAD OF AND BEHIND THE FRONT BRIEFLY.

THEN WINDS DIMINISH SUNDAY AS LOW PRESSURE PASSES JUST SOUTH.

TRANQUIL SEAS ARE EXPECTED TO BUILD AS THE WINDS INCREASE...THEN
SUBSIDE LATER THIS WEEKEND. WAVE WATCH III OUTPUT LOOKS REASONABLE.

SUB SCA CONDITIONS ARE EXPECTED SUNDAY NIGHT THROUGH TUESDAY. A COLD
FRONT MAY IMPACT THE WATERS WEDNESDAY WITH POSSIBLE SCA CONDITIONS
NEEDED WEDNESDAY AND WEDNESDAY NIGHT.

&&

.HYDROLOGY...
NO SIGNIFICANT PRECIPITATION IS EXPECTED THROUGH SATURDAY.

BASIN AVERAGES OF UP TO A HALF AN INCH ARE FORECAST FOR
SUNDAY. THIS WILL BE A STRATIFORM EVENT WITH A PROLONGED PERIOD OF
LIGHT TO MODERATE RAIN FROM LATE SUNDAY MORNING INTO THE FIRST HALF
OF SUNDAY NIGHT. THUS...FLOODING IS NOT EXPECTED.

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