LATEST FORECAST DISCUSSION FROM THE NY NATIONAL WEATHER SERVICE IN UPTON:

AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE NEW YORK NY 1100 AM EDT MON OCT 29 2012

SYNOPSIS... SANDY...WHOSE CENTER WAS LOCATED ABOUT 340 MILES SOUTH SOUTHEAST OF NEW YORK CITY AT 7 AM...CONTINUES TO INCREASE ITS IMPACT ON THE REGION THROUGH TONIGHT. THE CENTER OF SANDY IS FORECAST TO MAKE LANDFALL ON THE NEW JERSEY COAST THIS EVENING...A WORST CASE SCENARIO FOR OUR REGION. CONDITIONS WILL RAPIDLY DETERIORATE TODAY...WITH PROLONGED MAJOR IMPACTS THIS AFTERNOON AND NIGHT... INCLUDING DAMAGING WINDS TO HURRICANE FORCE...LIFE THREATENING STORM SURGE...AND POTENTIALLY FLOODING RAINS. THE STORM WILL WEAKEN JUST WEST OF THE REGION STARTING TUESDAY INTO WEDNESDAY. HIGH PRESSURE WILL BUILD IN FRIDAY INTO SATURDAY. &&
NEAR TERM /THROUGH TONIGHT/... GALE FORCE WIND GUSTS HAD ARRIVED TO THE CT COAST AS OF 7 AM...WHILE STEADY RAINS BEGIN TO MOVE IN FROM THE SOUTH. SANDY APPEARS TO BE GETTING READY TO TURN TOWARD THE NW IN RESPONSE TO INCREASING UPSTREAM BLOCKING AS AN UPPER HIGH BUILDS WESTWARD INTO THE CANADIAN MARITIMES...AND AS THE STORM FIRST UNDERGOES FUJIWARA INTERACTION WITH AND THEN MERGES WITH A DIGGING CLOSED LOW TO ITS WEST. THIS INFUSION OF BAROCLINIC ENERGY WILL ENABLE SANDY TO MAINTAIN OR INCREASE IN INTENSITY...TRANSFORMING INTO A SEVERE POST-TROPICAL CYCLONE AND MAKING LANDFALL ON THE CENTRAL OR SOUTHERN NJ COAST EARLY THIS EVENING. THE ALREADY LARGE WIND FIELD AROUND SANDY SHOULD EXPAND AND INTENSIFY TODAY...WITH SUSTAINED WINDS OF 35-45 MPH EXPECTED BY MID TO LATE AFTERNOON...AND 40-55 MPH THIS EVENING. ALL NWP IN PRETTY CLOSE AGREEMENT ON DEVELOPMENT AND PLACEMENT OF A BAND OF VERY STRONG 925 MB WINDS OF 70-90 KT TO THE NORTH OF THE CYCLONE BY LATE AFTERNOON OVER OUR CWA...ESPECIALLY ACROSS COASTAL SECTIONS. A SHALLOW MIXED LAYER BELOW THAT...IN COMBINATION WITH POSSIBLE GRAVITY WAVE DUCTING JUST NORTH OF A WARM FRONT DEVELOPING TO THE NORTHEAST OF SANDY...COULD ALLOW A LARGE PORTION OF THESE STRONG WINDS TO MIX DOWN...ESPECIALLY IN HEAVIER RAIN...SO AT LEAST OCCASIONAL GUSTS 60-75 MPH EXPECTED IN NE-E FLOW DURING MID TO LATE AFTERNOON BEFORE THE STORM MAKES LANDFALL. OF EVEN GREATER CONCERN IS A SECOND BAND OF FCST 925 MB WINDS OF SIMILAR STRENGTH ON THE SE FLANK OF THE CYCLONE THAT SHOULD ROTATE UP INTO THE CWA DURING AND JUST AFTER LANDFALL THIS EVENING...INITIALLY IMPACTING SOUTHERN CT AND LONG ISLAND...THEN TRANSLATING WESTWARD INTO NYC METRO AND THE LOWER HUDSON VALLEY. STEEPENING LOW LEVEL LAPSE RATES IN THIS QUADRANT OF THE STORM AS CAA BEGINS JUST OFF THE DECK...BUT AS LOW LEVEL WAA CONTINUES...SHOULD LEAD TO EVEN MORE EFFICIENT MOMENTUM TRANSFER...WITH THE STRONGEST WINDS EXPECTED ALONG THE SOUTH SHORES OF LONG ISLAND AND CT WHERE WINDS COULD GUST 80 TO PERHAPS 90 MPH. THERE MAY BE A LOW END TORNADO THREAT ACROSS EASTERN CT/LONG ISLAND DURING THIS TIME VIA STRONG LOW LEVEL HELICITY AND DEVELOPMENT OF MARGINAL LOW LEVEL CAPE...NOT ENOUGH FOR THUNDER INITIALLY BUT ENOUGH FOR LOW-TOPPED CONVECTION THAT COULD STRETCH ROTATING UPDRAFTS AND/OR TAP INTO HIGHER MOMENTUM ALOFT. WINDS WILL SLOWLY DIMINISH OVERNIGHT...BUT WILL STILL BE GUSTING UP TO 45-50 MPH AT DAYBREAK. THE COMBINATION OF EVENT DURATION...SATURATED GROUNDS...AND PARTIAL TO NEARLY FULL TREE CANOPIES...WOULD CAUSE WIDESPREAD DOWNING OF TREES AND POWER LINES...CAUSING DISRUPTION TO POWER AND POSSIBLY TRANSIT FOR AT LEAST SEVERAL DAYS. THESE WINDS WILL ALSO RESULT IN SIGNIFICANT COASTAL IMPACTS...DETAILED IN THE TIDES AND COASTAL FLOODING SECTION. THE HEAVIEST RAINFALL IS EXPECTED MONDAY INTO TUESDAY AS THE STORM INTERACTS WITH INTENSE JET/SHORTWAVE ENERGY...WITH 2 TO 4 INCHES RAINFALL POSSIBLE DURING THIS TIME. THINKING THE HIGHEST RAINFALL AMOUNTS WILL BE SEEN ACROSS NYC METRO AND NORTHEAST NEW JERSEY...CLOSER TO THE CENTER OF CIRCULATION...AND IN/NEAR UPSLOPE AREAS OF THE HIGHER ELEVATIONS OF THE LOWER HUDSON VALLEY AND SW CT VIA STRONG OROGRAPHIC LIFT. SEE THE HYDROLOGY SECTION FOR MORE DETAILS. LOWS TONIGHT IN THE 50S. CONTINUE TO MONITOR NATIONAL WEATHER SERVICE FORECASTS...AS THE EXACT TIMING...PLACEMENT AND INTENSITY OF THE STORM AS IT APPROACHES AND MAKES LANDFALL WILL DETERMINE THE SEVERITY OF IMPACTS IN PARTICULAR LOCATIONS. ALSO...REFER TO THE NATIONAL HURRICANE CENTER FOR THE LATEST TRACK AND FORECASTS. &&
George Wright is a Certified Consulting Meteorologist for Wright Weather Consulting, LLC. George is also a meteorologist with ABC News and Cablevision News 12. Our website is WrightWeather.com.