Ida takes aim at the U.S. Gulf Coast
Hurricane Ida burst into the Gulf of Mexico as a Category 2 hurricane with 100 mph winds this afternoon, and is poised to deliver a solid blow to the U.S. Gulf Coast between Southeast Louisiana and the Florida Panhandle on Tuesday morning. Radar imagery out of Cancun reveals that Ida has retained its tight inner core this afternoon, with only limited rain bands affecting Mexico and western Cuba. Top winds at Cancun, Mexico today were only 15 mph, despite the fact that Ida passed just 60 miles east of the city. Infrared and visible satellite loops show little change in the intensity of Ida's heavy thunderstorms this afternoon, but the cloud pattern is beginning to become distorted due to strong upper-level winds from the southwest that are creating 20 - 25 knots of wind shear over the hurricane. Water vapor satellite imagery reveals a large area of dry air to the southwest of Ida, but this dry air has not yet intruded into Ida's core. The latest 5:30 pm EST vortex report from the Hurricane Hunters showed that the central pressure had risen 1 mb, to 977 mb, but that the surface winds were still near 100 mph. They noted that the eyewall was open to the east, a sign that Ida's inner core may be in trouble.
Figure 1. MODIS satellite image from NASA's Terra spacecraft, taken at 1:35 pm EST 11/08/09. Image credit: NASA.
The intensity forecast for Ida
The high wind shear of 20 - 25 knots currently affecting Ida is forecast to persist at that level until Monday night. With the storm now beginning to show a distortion of the cloud pattern due to this shear, it would not be a surprise of the shear managed to inject some dry air into Ida's core Monday morning, significantly weakening the storm. Aiding this process will be cooler waters. Early Monday morning, Ida will be crossing over waters of 26°C, which is barely enough to support a hurricane. By Monday night, wind shear is expected to increase to 40 knots, which ordinarily would begin to tear the storm apart. This wind shear is due to an extratropical low pressure system over the western Gulf of Mexico, and this low will begin dumping cold, stable air into Ida Monday night through Tuesday. This will cause Ida to begin transitioning to an extratropical storm, and it is possible that during the transition Ida's winds will die down relatively slowly, despite the wind shear. The intensity forecast has a high amount of uncertainty, and I wouldn't be surprised at a landfall strength anywhere in the range of 45 mph - 80 mph. My personal best guess is a 50 - 60 mph tropical storm at landfall. Regardless of Ida's strength at landfall, the storm will be able to dump 4 - 8 inches of rain along the Gulf Coast, from New Orleans to Panama City. Isolated tornadoes will also be possible, primarily to the right side of Ida's track.
Figure 2. Maximum storm surge (depth of water above ground) for a Category 1 hurricane with 85 mph winds moving north-northeast at 15 mph. Ida is expected to be moving at this speed and direction at landfall, but will probably be weaker, so surges will not be this high. Image credit: NOAA SLOSH model run for Mobile Bay, 2008 version. Heights are given relative to the NAVD88 datum.
The storm surge forecast for Ida
Storm surge is the other major concern for Ida. With a strong high pressure system anchored over the U.S. today, the pressure difference between this high and Ida is creating a strong pressure gradient that will drive tides 3 - 5 feet above normal from New Orleans to the Florida Panhandle tonight. As Ida approaches on Monday, an additional rise in water will occur, and a large stretch of coast will be subject to very high water levels for an extended period of time. With battering waves building Monday afternoon into Tuesday morning, a significant coastal erosion event is shaping up. A particular concern is the western end of Alabama's Dauphin Island, where storm surges from four hurricanes over the past fifteen years have caused heavy damage to the low-lying heavily developed island. If Ida makes a direct hit on Mobile Bay as a Category 1 hurricane with 85 mph winds, a storm surge of up to six feet is possible there, assuming the storm hits at mean tide. The tidal range along the Gulf Coast varies by about 1.5 feet between low and high tide (Figure 3). High tide is near 2 am EST on Tuesday, but the official NHC forecast currently has the storm hitting between 6 am - 9 am, when the tide will be going out, so the storm may indeed be hitting at about mean tide.
Figure 3. The tide forecast for the Gulf Coast calls for high tide to occur around 2 am EST Tuesday morning. Ida is expected to hit later that morning, while the tide is going out.
I'll have an update Monday morning.
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Cancun radar
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TS BUSTED FORECAST, to be used in the event you make a minor discrepancy in your forecast.
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Agreed. Extremely knowledgeable, the only reason to ever put on TWC.
Still have 2-3 more advisories before landfall, so it will change most likely.
I found this interesting reading...not stuff you see everyday... It would be nice to get some good rain here!
AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE RALEIGH NC
636 AM EST MON NOV 9 2009
FORECAST CONFIDENCE ... REMAINS RELATIVELY LOW... AND IS A RESULT OF THE COMPLEX INTERACTION OF:
1) TROPICAL CYCLONE IDA (AND ASSOCIATED MESOSCALE OUTFLOW JET)...
2) A PAIR OF SPLIT SOUTHERN STREAM TROUGHS ALOFT (AND UPPER JETS) OVER CENTRAL TX AND THE WESTERN GULF OF MEXICO...
3) ANOTHER UPSTREAM SOUTHERN STREAM S/W TROUGH ALOFT OVER THE FOUR CORNERS REGION...
4) NORTHERN STREAM ENERGY OVER WEST CENTRAL CANADA... AND MOST NOTABLY
5) A *POSSIBLE * DIABATICALLY-INDUCED LOW LEVEL PV ANOMALY ALONG AN INVERTED H85 FRONTAL ZONE TO THE NORTHEAST OF THE CENTER OF IDA. FAVOR A SOLUTION DEPICTED BY A BLEND OF THE 00Z/9TH GEM AND ECMWF FOR REASONS OUTLINED BELOW.
DESPITE INEVITABLE TIMING AND LOCATION DIFFERENCES WRT THE EVOLUTION OF THOSE FEATURES... THERE CONTINUES TO BE A DOMINANT SIGNAL OF STRONG JET ENTRANCE REGION JET DYNAMICS -- FIRST FROM THE SOUTHERN STREAM TROUGH AND MESOSCALE OUTFLOW JET FROM THE SOUTH AND THEN FROM A PHASING OF THIS JET WITH THE NORTHERN STREAM PJ -- WITHIN A DEEP 1.5 TO 2.0 INCH PWAT TROPICAL MOISTURE PLUME.
HIGHER PRECIPITATION AMOUNTS (AND LONGER DURATION BY WEDNESDAY AND BEYOND) ARE CONTINGENT UPON WHETHER OR NOT A LOW LEVEL PV ANOMALY INDEED DEVELOPS UP THE SOUTHEAST US AND MID ATLANTIC COAST ALONG THE INVERTED H85 FRONT. FOR THE PAST COUPLE OF DAYS...MOST/ALL OF THE OPERATIONAL MODELS HAVE SUPPRESSED THE PRIMARY LOW LEVEL PV TOWER (CIRCULATION) OF IDA ALONG THE VICINITY OF THE GULF COAST... WHICH TPC TRACK GUIDANCE HAS REFLECTED. THE MSLP WAVE THE MODELS HAVE LIFTED NORTHEASTWARD...WHICH SOME (MAINLY THE GFS/GEM) HAVE BOMBED OFF THE CAROLINA COASTLINE...IS NOT IDA ACCORDING TO LOW LEVEL PV DIAGNOSTICS...AND INSTEAD A FUNCTION OF THE INTENSE LATENT HEATING FROM SIMULATED DEEP CONVECTION ABOVE (CONVECTIVE FEEDBACK).
IF ONE OF THESE LOW LEVEL PV ANOMALIES INDEED DEVELOPS...IT WOULD SUBSEQUENTLY ACCELERATE THE LOW LEVEL FLOW INTO THE H85 FRONT AND LEAD TO STRONGER FORCING FOR ASCENT AND PRECIPITATION (VIA MOISTURE TRANSPORT...ISENTROPIC LIFT...MASS CONVERGENCE...FGEN...ETC.) IT WOULD ALSO CONTRIBUTE TO A STRONGER LOW LEVEL THERMAL ADVECTION PATTERN WHICH COULD THEN FEED BACK TO THE APPROACHING NORTHERN STREAM TROUGH THROUGH SUTCLIFFE-PETTERSSEN "SELF-DEVELOPMENT"...AND LEAD TO THE INTENSE "PHASE-LOCKED"/OCCLUDED LOW OFF THE MID ATLANTIC COAST THAT THE OPERATIONAL GFS/ECMWF/GEM HAVE SHOWN FOR A COUPLE OF DAYS (AND THE LONE 00Z/9TH GFS STILL DOES).
WHILE SUCH A SCENARIO IS PHYSICALLY PLAUSIBLE...IT IS DEEMED A LOW PROBABILITY SOLUTION... PARTICULARLY SINCE ONLY THE CONVECTIVE FEEDBACK-PRONE GFS STILL CREATES THIS FANTASY. IT SHOULD BE NOTED THAT ANY SUCH FEATURE LIKELY WOULD NOT SHOW UP IN OBSERVATIONAL DATA OVER GA/SC AND SWAY FORECAST CONFIDENCE TOWARD SUCH A WETTER SOLUTION UNTIL LATE TONIGHT OR MORE LIKELY TUESDAY.
West End of Dauphin Island already under water. Mandatory evacuation.
Link
Right back at you
Sheri
NATIONAL WEATHER SERVICE RALEIGH NC
636 AM EST MON NOV 9 2009
FORECAST CONFIDENCE ... REMAINS RELATIVELY LOW... AND IS A RESULT OF THE COMPLEX INTERACTION OF:
1) TROPICAL CYCLONE IDA (AND ASSOCIATED MESOSCALE OUTFLOW JET)...
2) A PAIR OF SPLIT SOUTHERN STREAM TROUGHS ALOFT (AND UPPER JETS) OVER CENTRAL TX AND THE WESTERN GULF OF MEXICO...
3) ANOTHER UPSTREAM SOUTHERN STREAM S/W TROUGH ALOFT OVER THE FOUR CORNERS REGION...
4) NORTHERN STREAM ENERGY OVER WEST CENTRAL CANADA... AND MOST NOTABLY
5) A *POSSIBLE * DIABATICALLY-INDUCED LOW LEVEL PV ANOMALY ALONG AN INVERTED H85 FRONTAL ZONE TO THE NORTHEAST OF THE CENTER OF IDA. FAVOR A SOLUTION DEPICTED BY A BLEND OF THE 00Z/9TH GEM AND ECMWF FOR REASONS OUTLINED BELOW.
DESPITE INEVITABLE TIMING AND LOCATION DIFFERENCES WRT THE EVOLUTION OF THOSE FEATURES... THERE CONTINUES TO BE A DOMINANT SIGNAL OF STRONG JET ENTRANCE REGION JET DYNAMICS -- FIRST FROM THE SOUTHERN STREAM TROUGH AND MESOSCALE OUTFLOW JET FROM THE SOUTH AND THEN FROM A PHASING OF THIS JET WITH THE NORTHERN STREAM PJ -- WITHIN A DEEP 1.5 TO 2.0 INCH PWAT TROPICAL MOISTURE PLUME.
HIGHER PRECIPITATION AMOUNTS (AND LONGER DURATION BY WEDNESDAY AND BEYOND) ARE CONTINGENT UPON WHETHER OR NOT A LOW LEVEL PV ANOMALY INDEED DEVELOPS UP THE SOUTHEAST US AND MID ATLANTIC COAST ALONG THE INVERTED H85 FRONT. FOR THE PAST COUPLE OF DAYS...MOST/ALL OF THE OPERATIONAL MODELS HAVE SUPPRESSED THE PRIMARY LOW LEVEL PV TOWER (CIRCULATION) OF IDA ALONG THE VICINITY OF THE GULF COAST... WHICH TPC TRACK GUIDANCE HAS REFLECTED. THE MSLP WAVE THE MODELS HAVE LIFTED NORTHEASTWARD...WHICH SOME (MAINLY THE GFS/GEM) HAVE BOMBED OFF THE CAROLINA COASTLINE...IS NOT IDA ACCORDING TO LOW LEVEL PV DIAGNOSTICS...AND INSTEAD A FUNCTION OF THE INTENSE LATENT HEATING FROM SIMULATED DEEP CONVECTION ABOVE (CONVECTIVE FEEDBACK).
IF ONE OF THESE LOW LEVEL PV ANOMALIES INDEED DEVELOPS...IT WOULD SUBSEQUENTLY ACCELERATE THE LOW LEVEL FLOW INTO THE H85 FRONT AND LEAD TO STRONGER FORCING FOR ASCENT AND PRECIPITATION (VIA MOISTURE TRANSPORT...ISENTROPIC LIFT...MASS CONVERGENCE...FGEN...ETC.) IT WOULD ALSO CONTRIBUTE TO A STRONGER LOW LEVEL THERMAL ADVECTION PATTERN WHICH COULD THEN FEED BACK TO THE APPROACHING NORTHERN STREAM TROUGH THROUGH SUTCLIFFE-PETTERSSEN "SELF-DEVELOPMENT"...AND LEAD TO THE INTENSE "PHASE-LOCKED"/OCCLUDED LOW OFF THE MID ATLANTIC COAST THAT THE OPERATIONAL GFS/ECMWF/GEM HAVE SHOWN FOR A COUPLE OF DAYS (AND THE LONE 00Z/9TH GFS STILL DOES).
WHILE SUCH A SCENARIO IS PHYSICALLY PLAUSIBLE...IT IS DEEMED A LOW PROBABILITY SOLUTION... PARTICULARLY SINCE ONLY THE CONVECTIVE FEEDBACK-PRONE GFS STILL CREATES THIS FANTASY. IT SHOULD BE NOTED THAT ANY SUCH FEATURE LIKELY WOULD NOT SHOW UP IN OBSERVATIONAL DATA OVER GA/SC AND SWAY FORECAST CONFIDENCE TOWARD SUCH A WETTER SOLUTION UNTIL LATE TONIGHT OR MORE LIKELY TUESDAY.
Can I get a translator for this please? the short version would be just fine!
thx
No suprise there. It will get much worse during the next 20 hours or so.
Digging towards the Big Bend of TX at this time.
The whole mess, including Ida will go with it spreading a large rain shield over the SE and TN Valley.
Not downplaying any weather associated with it but would have to strongly disagree on anything here that is a hybrid. Just an opinion.
RAMSDIS WV/IR
Indeed!
Uhhh ok I'll give it a go. Most likely we (I say we since I'm in Raleigh) will get just some heavy rain from whats left of Ida but there is a chance that all of the energy from her convection meeting the front could spin up a fairly strong low off the Carolina coast which would bring in a lot more heavy rains and high winds. Right now they don't believe it will happen since the only models that shows it is prone to over develop storms. If it was to happen we wouldn't know it until it had already started forming which is late tonight or early tomorrow.
Hey Floodman, nice to see ya. Weird how people try to throw words at cha. You been on this site a long time and we all know what DrM rules of the road are.
What cha think about Ida? I was lurking last night for a while and never seen ya last night.
Sheri
I know all the conversation is on Ida, but anything on that blob NE of the islands? Probably just the normal November convection flaring. Just figured it could add some additional tropics discussion. I'm ready for the blasts. Go ahead.
Lord i need to let my daughter know that there opening a new Freds in Bayou La Batre they have been working 16hr days. Thanks for the info.
Sheri
WELL LIKE I SAID LAST NIGHT---IDA--GOING--GOING
GOING--THEN LATER--WILL HIT SHORE AT ABOUT 43MPH MAX WINDS ARE NOT 70MPH---THEY ARE 47MPH
WITH GUSTS AT 53MPH ---GOING-GOING -GOING---
ALMOST GONE OIL RIGS ARE SAFE--PRICE OF GAS
SHOULD REMAIN CLOSE TO THE SAME AS IT WAS
GOD IS GREAT --(WINDS AS OF 12.41PM ET.)
Viewing: 1851 - 1891
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