Now starring HURRICANE Sandy (and TS Tony)

By: hcubed , 4:25 PM GMT on October 24, 2012

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HURRICANE SANDY DISCUSSION NUMBER 9
NWS NATIONAL HURRICANE CENTER MIAMI FL AL182012
1100 AM EDT WED OCT 24 2012

DATA FROM THE HURRICANE HUNTER AIRCRAFT INDICATE THAT SANDY HAS REACHED HURRICANE STRENGTH. THE AIRCRAFT JUST MEASURED A PEAK 700-MB FLIGHT-LEVEL WIND OF 86 KT...AND BLENDING THAT WITH THE PEAK SFMR WINDS YIELDS AN INITIAL INTENSITY OF 70 KT. THE CENTRAL PRESSURE HAS ALSO FALLEN TO 973 MB BASED ON DATA FROM THE PLANE. CONDITIONS APPEAR FAVORABLE FOR ADDITIONAL INTENSIFICATION UNTIL THE CYCLONE MOVES NEAR OR OVER EASTERN JAMAICA...AND THE OFFICIAL FORECAST SHOWS SOME STRENGTHENING AT 12 HOURS. AFTER THAT TIME...ADDITIONAL LAND INTERACTION WITH EASTERN CUBA AND STRUCTURAL CHANGES DUE TO INTERACTION WITH AN UPPER-LEVEL TROUGH MAKE THE INTENSITY FORECAST HIGHLY UNCERTAIN. INCREASING SHEAR SHOULD RESULT IN LESS FAVORABLE CONDITIONS FOR INTENSIFICATION VIA LATENT HEAT RELEASE...BUT THIS COULD BE COMPENSATED FOR BY BAROCLINIC PROCESSES. GIVEN THE UNCERTAINTY...THE NHC INTENSITY FORECAST REMAINS UNCHANGED AT 36 HOURS AND BEYOND...SHOWING SANDY BECOMING A POWERFUL POST-TROPICAL CYCLONE BY THE END OF THE PERIOD.

THE INITIAL MOTION IS 015/11. THE SHORT-TERM TRACK FORECAST REASONING REMAINS UNCHANGED FOR THE FIRST COUPLE OF DAYS...AS SANDY SHOULD MOVE GENERALLY NORTHWARD INTO A BREAK IN THE SUBTROPICAL RIDGE OVER THE BAHAMAS AS IT INTERACTS WITH AN UPPER-LEVEL LOW TO ITS WEST. LATE IN THE PERIOD...THERE REMAINS CONSIDERABLE SPREAD IN THE GUIDANCE DUE TO DIFFERENCES IN HOW MUCH SANDY INTERACTS WITH ANOTHER TROUGH MOVING INTO THE NORTHEASTERN UNITED STATES. THE ECMWF HAS BEEN CONSISTENT IN SHOWING MORE INTERACTION AND A TRACK FARTHER WEST...WHILE THE GFS SHOWS SANDY TURNING EAST AND MISSING THE TROUGH. OVERALL MORE OF THE GUIDANCE HAS BEEN TRENDING TOWARD SHOWING MORE INTERACTION WITH THE EASTERN U.S. TROUGH LATE IN THE PERIOD. GIVEN THIS TREND...THE NHC FORECAST HAS BEEN ADJUSTED TO THE LEFT AT DAYS 4 AND 5...AND LIES ROUGHLY BETWEEN THE ECMWF AND THE TVCA MULTI-MODEL CONSENSUS. NEEDLESS TO SAY...THE TRACK FORECAST UNCERTAINTY REMAINS HIGH AT THE END OF THE PERIOD.

GIVEN THE LATEST NHC FORECAST...A HURRICANE WATCH HAS BEEN ISSUED FOR THE CENTRAL AND NORTHWEST BAHAMAS...AND THE TROPICAL STORM WATCH HAS BEEN EXTENDED NORTHWARD ALONG THE EAST-CENTRAL FLORIDA COAST.

Looks like Fla will be getting more than planned. But still no Major forecasted.

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3. WunderAlertBot (Admin)
2:13 AM GMT on October 27, 2012
hcubed has created a new entry.
2. hcubed
11:29 AM GMT on October 25, 2012
Tony seems to be taking a back seat at this time, as all eyes are centered on Sandy.

Once again, if you're on the east coast, you should be aware of this storm, and making early prep.

In about 5 days, the DelMarVa area could see a real mess.

000
WTNT43 KNHC 250902
TCDAT3

HURRICANE SANDY DISCUSSION NUMBER 12
NWS NATIONAL HURRICANE CENTER MIAMI FL AL182012
500 AM EDT THU OCT 25 2012

EARLIER THIS MORNING...SANDY MADE LANDFALL JUST WEST OF SANTIAGO DE CUBA AS A STRONG CATEGORY TWO HURRICANE. CUBAN RADAR DATA AND REPORTS FROM AN AIR FORCE RESERVE RECONNAISSANCE AIRCRAFT INDICATED THAT SANDY HAD A WELL-DEFINED 20-24 N MI DIAMETER EYE WHEN IT MADE LANDFALL. THE AIRCRAFT REPORTED MAXIMUM 700-MB FLIGHT-LEVEL WINDS OF 117 KT AND BIAS-CORRECTED SFMR SURFACE ESTIMATES OF 91-92 KT. A BLEND OF THESE DATA YIELDS A SURFACE WIND ESTIMATE OF 99 KT...JUST BELOW MAJOR HURRICANE STATUS. THE MAIN REASON WHY SANDY WAS HELD JUST BELOW MAJOR HURRICANE STATUS WAS DUE TO THE SUSTAINED 68-KT WIND AND GUST TO 99 KT THAT OCCURRED AROUND 0517Z. HOWEVER...STRONGER WINDS MAY HAVE OCCURRED LATER WHEN THE SOUTHEASTERN PORTION OF THE EYEWALL MOVED ONSHORE...WHICH IS THE QUADRANT WHERE THE 117-KT FLIGHT-LEVEL WIND WAS OBSERVED. THE INITIAL INTENSITY OF 90 KT IS BASED ON WIND DECAY MODELS FOR HURRICANES OVER LAND.

THE INITIAL MOTION IS 005/16 KT. AFTER A SLIGHT JOG TO THE NORTH-NORTHEAST VERY EARLY THIS MORNING...SANDY APPEARS TO HAVE RESUMED A NORTHWARD MOTION...AND THIS GENERAL MOTION IS EXPECTED TO CONTINUE FOR THE NEXT 24 HOURS OR SO. AFTER THAT...A DEEP-LAYER TROUGH OVER THE NORTHERN U.S. AND A SIMILAR DEEP-LAYER TROUGH OVER THE NORTH ATLANTIC EAST OF NEWFOUNDLAND ARE FORECAST TO AMPLIFY...WHICH WILL INDUCE MID-LEVEL RIDGING NEAR THE NORTHEAST U.S. COAST BETWEEN THOSE TWO SYSTEMS. THAT RIDGE IS EXPECTED TO CAUSE SANDY TO SLOW DOWN AND TURN TOWARD THE NORTH-NORTHWEST IN 24-36 HOURS. AFTER THAT...THE RIDGE TO THE NORTH OF SANDY IS FORECAST TO WEAKEN AS AN APPROACHING DEEP MID-LATITUDE TROUGH MOVES OVER THE EASTERN HALF OF THE UNITED STATES BY 72 HOURS AND BEGINS TO ACCELERATE SANDY TO THE NORTHEAST. THE NHC MODEL GUIDANCE IS IN EXCELLENT AGREEMENT ON THIS DEVELOPING SCENARIO. AFTER THAT...HOWEVER...THE GUIDANCE DIVERGES SIGNIFICANTLY WITH THE ECMWF...GFDL...AND NOGAPS TAKING SANDY NORTHWESTWARD AND INLAND OVER THE DELMARVA PENINSULA BY 120 HOURS...WHEREAS THE GFS MODEL KEEPS SANDY MOVING NORTHEASTWARD AWAY FROM THE U.S. AND OVER THE OPEN NORTH ATLANTIC. THE REMAINDER OF THE MODEL GUIDANCE IS SOMEWHERE IN BETWEEN THESE TWO EXTREMES. GIVEN THE HISTORICAL RELIABILITY OF THE VERY CONSISTENT ECMWF MODEL OVER THE PAST 2 DAYS...THE OFFICIAL FORECAST WAS TURNED SLIGHTLY MORE TOWARD THE NORTHWEST AT 120 HOURS...AND IS CLOSE TO A BLEND OF THE CONSENSUS MODELS TV15 AND TVCN...AND THE FSU TRACK MODEL.

OWING TO THE HIGHER CURRENT INTENSITY OF SANDY...THE NEW INTENSITY FORECAST IS ALSO HIGHER THAN THE PREVIOUS FORECAST THROUGH 36 HOURS...AND THEN IS SIMILAR TO THE PREVIOUS ADVISORY INTENSITY FORECAST AS INCREASING SHEAR BEGINS TO AFFECT THE CYCLONE. THE MAIN FORECAST CHALLENGE IS DETERMINING JUST HOW MUCH BAROCLINIC INFLUENCE THE DEEP TROUGH OVER THE EASTERN U.S. WILL HAVE ON SANDY...AND ALSO WHAT THE VERTICAL STRUCTURE OF SANDY WILL BE AFTER 48 HOURS. ALL OF THE GLOBAL MODELS MAINTAIN SIGNIFICANT RAINFALL AMOUNTS IN EXCESS OF 2 INCHES NEAR THE CENTER THROUGH 120 HOURS...WHICH SUGGESTS THAT SANDY WILL MAINTAIN SOME CONVECTION AND POSSIBLY AN INNER-CORE WARM STRUCTURE THAT WOULD KEEP SOME TROPICAL CHARACTERISTICS ASSOCIATED WITH THE SYSTEM. THE NEW INTENSITY FORECAST IS SIMILAR TO THE LGEM AND DECAY-SHIPS INTENSITY MODELS. THE FORECAST WILL STILL CALL FOR SANDY TO BECOME POST-TROPICAL BY 120 HOURS...ALTHOUGH THIS REMAINS LOW CONFIDENCE.

So Sandy got to Cat 2 before hitting Cuba. We'll see if she recovers enough to make Cat 3 or above.

Member Since: May 18, 2007 Posts: 289 Comments: 1639
1. hcubed
6:52 PM GMT on October 24, 2012
Well, us here in Biloxi are safe, but in New England, potential for doom coming in:

GOING INTO THE WEEKEND AND EARLY NEXT WEEK, MUCH UNCERTAINTY REMAINS WITH REGARDS TO THE TIMING OF AN APPROACHING COLD FRONT FROM THE WEST AND ALSO THE TRACK OF TROPICAL SYSTEM SANDY. THE ECMWF CONTINUES TO HAVE THE MOST WESTWARD TRACK OF SANDY, BUT SOME GFS ENSEMBLE MEMBERS ARE ALSO SHOWING A SIMILAR SOLUTION. STILL, OTHER MODEL DATA RECURVES SANDY MORE SHARPLY AND TAKES THE SYSTEM MORE EAST AND OUT TO SEA. IN COLLABORATING WITH NEIGHBORING OFFICES AND WITH THIS MUCH UNCERTAINTY AT THIS LONG RANGE PERIOD, WE HAVE MADE SMALL CHANGES TO THE END OF THE EXTENDED FCST. AS MODEL SOLUTIONS COME TO CLOSER AGREEMENT, ADDITIONAL ADJUSTMENTS CAN BE MADE TO THIS TIMEFRAME. FOR NOW, THE INTERACTION OF THE SLOW MOVING COLD FRONT AND THE TROPICAL OR POST-TROPICAL SYSTEM HAS THE POTENTIAL TO PRODUCE HIGH WINDS, HEAVY RAIN, RIVER/STREAM FLOODING, AND COASTAL FLOODING. AS THIS IS A POTENTIALLY HIGH IMPACT EVENT, WE WILL CONTINUE TO HIGHLIGHT THIS SYSTEM IN OUR HAZARDOUS WEATHER OUTLOOK.
Member Since: May 18, 2007 Posts: 289 Comments: 1639

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About hcubed

Living in Biloxi MS, have been here since '85 (first Hurricane was Elena).

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