A Case Study in Weather Forecasting:

Hurricane Georges


This case is told by Petty Officer Trisha Bednarczk, a forecaster at the NASP METOC. She has been forecasting since 1990, including service at NAS-Dallas, Crete and Baharain,. She has logged over 13,300 hours at forecasting and forecasting-related tasks.



This case involves a tropical hurricane that not only entered the Gulf  of Mexico but made landfall in the Panhandle region and impacted operations at NASP.   This case shows the vigilant analysis of hurricane tracks, the use of hand chart work  using bouy data to forecast hurricane tracks, and also illustrates how the Naval forecaster is sometimes in a position of disagreeing in certain ways with forecast products from the National Hurricane Center.



OSA = Observation /  Situation Assessment              D = Decision              A = Action

 

Event

OSA, D,

A

Time

Hurricane Georges.

September 26 - 29.

 

 

Georges crossed the Florida Keys on September 25 - 26.

See the enhanced infrared image of Georges entering the Gulf of Mexico.

 

OSA

 




I came on midwatch duty Saturday evening, September 27.

Mr. Etheridge was at the radar.

The HDO was Chief Womack.

I was the Forecaster.

COR-4 had been set four days earlier.

METOC was in COR-3 and was going to COR -2.

We were here with blankets, books, food, flashlights, and camped out all weekend.

The National Hurricane Center had Georges tracking west-northwest.

See NHC advisory #48 (below).

 

OSA, D

5:00 PM

 

 

ZCZC MIATCPAT2 ALL

TTAA00 KNHC DDHHMM

BULLETIN

HURRICANE GEORGES ADVISORY NUMBER  48

NATIONAL WEATHER SERVICE MIAMI FL

4 AM CDT SUN SEP 27 1998

 

...DANGEROUS HURRICANE GEORGES APPROACHING THE WARNING AREA...BE PREPARED...

 

A HURRICANE WARNING IS IN EFFECT FROM MORGAN CITY LOUISIANA TO

PANAMA CITY FLORIDA.  A HURRICANE WARNING MEANS THAT HURRICANE CONDITIONS ARE EXPECTED IN THE WARNED AREA WITHIN 24 HOURS. PREPARATIONS TO PROTECT LIFE AND PROPERTY SHOULD BE RUSHED TO COMPLETION.

 

A TROPICAL STORM WARNING AND A HURRICANE WATCH ARE IN EFFECT FROM EAST OF PANAMA CITY FLORIDA TO ST. MARKS FLORIDA.  A HURRICANE WATCH IS IN EFFECT FROM WEST OF MORGAN CITY TO INTRACOASTAL CITY LOUISIANA.

 

AT 4 AM CDT...0900Z...THE CENTER OF HURRICANE GEORGES WAS LOCATED NEAR LATITUDE 28.1 NORTH...LONGITUDE  87.6 WEST. THIS POSITION IS ABOUT 110 MILES SOUTHEAST OF THE MOUTH OF THE MISSISSIPI RIVER AND ABOUT 200 MILES SOUTHEAST OF NEW ORLEANS.

 

GEORGES IS MOVING TOWARD THE NORTHWEST NEAR 10 MPH AND THIS MOTION IS EXPECTED TO CONTINUE TODAY WITH SOME DCREASE IN FORWARD SPEED. OUTER BANDS SHOULD GRADUALLY BEGIN TO SPREAD ACROSS THE COASTAL

SECTIONS WITHIN THE WARNING AREA SOON AND HURRICANE FORCE WINDS SHOULD BEGIN TO AFFECT THE AREA LATER TODAY.

 

MAXIMUM SUSTAINED WINDS ARE NEAR 110 MPH WITH HIGHER GUSTS. GEORGES IS A STRONG CATEGORY TWO HURRICANE ON THE SAFFIR/SIMPSON HURRICANE SCALE.  SOME FLUCTUATIONS IN INTENSITY ARE EXPECTED BEFORE LANDFALL.

 

HURRICANE FORCE WINDS EXTEND OUTWARD UP TO 115 MILES FROM THE

CENTER...AND TROPICAL STORM FORCE WINDS EXTEND OUTWARD UP TO 175 MILES MAINLY TO THE EAST.

 

ESTIMATED MINIMUM CENTRAL PRESSURE IS  970 MB...28.64 INCHES.

 

STORM SURGE FLOODING OF 10 TO 15 FEET...UP TO 17 FEET AT THE HEADS OF BAYS...ABOVE NORMAL TIDE LEVELS IS POSSIBLE IN THE WARNED AREA AND WILL BE ACCOMPANIED BY LARGE AND DANGEROUS BATTERING WAVES.

 

FLOODING RAINS ARE LIKELY IN ASSOCIATION WITH GEORGES AND WILL

BECOME PARTICULARLY SEVERE IF GEORGES FORWARD MOTION DECREASES NEAR LANDFALL AS IS NOW FORECAST.

 

SMALL CRAFT FROM INTRACOASTAL CITY TO HIGH ISLAND TEXAS SHOULD REMAIN IN PORT.  SMALL CRAFT ALONG THE WEST COAST OF THE FLORIDA PENINSULA SHOULD REMAIN IN PORT UNTIL WINDS AND SEAS SUBSIDE.

 

REPEATING THE 4 AM CDT POSITION...28.1 N... 87.6 W.  MOVEMENT

TOWARD...NORTHWEST NEAR 10 MPH.  MAXIMUM SUSTAINED WINDS...110 MPH.  MINIMUM CENTRAL PRESSURE... 970 MB.

 

AN INTERMEDIATE ADVISORY WILL BE ISSUED BY THE NATIONAL HURRICANE CENTER AT 7 AM CDT FOLLOWED BY THE NEXT COMPLETE ADVISORY AT 10 AM CDT.

 

AVILA




METOC administration had decided to continue the regular watch sections over the weekend.

 

D

 

Planes had sortied out by Saturday and Sunday, and remaining planes had been stored by Sunday afternoon.

Ships had left by Friday to head toward Yucatan.

See NHC Advisory #50 (below).

 

OSA

4:00PM

 

 

 

ZCZC MIATCPAT2 ALL

TTAA00 KNHC DDHHMM

BULLETIN

HURRICANE GEORGES ADVISORY NUMBER  50

NATIONAL WEATHER SERVICE MIAMI FL

4 PM CDT SUN SEP 27 1998

 

...DANGEROUS HURRICANE GEORGES CLOSING IN ON THE CENTRAL GULF

COAST...

 

A HURRICANE WARNING IS IN EFFECT FROM MORGAN CITY LOUISIANA TO

PANAMA CITY FLORIDA.  A HURRICANE WARNING MEANS THAT HURRICANE CONDITIONS ARE EXPECTED IN THE WARNED AREA WITHIN 24 HOURS. PREPARATIONS TO PROTECT LIFE AND PROPERTY SHOULD BE RUSHED TO COMPLETION.

 

A TROPICAL STORM WARNING IS IN EFFECT FROM EAST OF PANAMA CITY

FLORIDA TO ST. MARKS FLORIDA.  A HURRICANE WATCH IS IN EFFECT FROM WEST OF MORGAN CITY TO INTRACOASTAL CITY LOUISIANA.

 

AT 4 PM CDT...2100Z...THE HURRICANE WATCH FROM EAST OF PANAMA CITY FLORIDA TO ST. MARKS FLORIDA IS DISCONTINUED.

 

AT 4 PM CDT THE CENTER OF HURRICANE GEORGES WAS LOCATED NEAR

LATITUDE 29.0 NORTH...LONGITUDE  88.5 WEST. THIS POSITION IS ABOUT

40 MILES EAST OF THE MOUTH OF THE MISSISSIPPI RIVER AND ABOUT 125

MILES EAST-SOUTHEAST OF NEW ORLEANS LOUISIANA.

 

THE TRACK OF GEORGES IS WOBBLING A LITTLE ALONG A NORTHWEST HEADING NEAR  8 MPH AND THIS MOTION IS EXPECTED TO CONTINUE THROUGH TONIGHT BRINGING THE CORE OF THE HURRICANE NEARER TO THE COAST. DO NOT FOCUS ON THE PRECISE LOCATION AND TRACK OF THE CENTER.  THE HURRICANES DESTRUCTIVE WINDS...RAIN...AND STORM SURGE COVER A WIDE SWATH.

 

MAXIMUM SUSTAINED WINDS REMAIN NEAR 110 MPH WITH HIGHER GUSTS.  SOME FLUCTUATIONS IN STRENGTH ARE LIKELY BEFORE LANDFALL AND GEORGES COULD STILL BECOME A CATEGORY 3 HURRICANE.

 

HURRICANE FORCE WINDS EXTEND OUTWARD UP TO  70 MILES EAST OF THE CENTER...AND TROPICAL STORM FORCE WINDS EXTEND OUTWARD UP TO 185 MILES.  RAINBANDS OF GEORGES ARE SPREADING ACROSS PORTIONS OF THE WARNING AREA.  THE AUTOMATED OBSERVING SITE AT DAUPHIN ISLAND ALABAMA RECENTLY REPORTED A 58 MPH WIND SUSTAINED OVER TWO MINUTES WITH A PEAK GUST TO HURRICANE FORCE...74 MPH.  WINDS WILL CONTINUE TO INCREASE IN THE WARNING AREA THIS EVENING AND TONIGHT.

 

AN AIR FORCE RESERVE UNIT HURRICANE HUNTER PLANE REPORTED A MINIMUM CENTRAL PRESSURE OF 961 MB...28.38 INCHES.

 

STORM SURGE FLOODING OF 10 TO 15 FEET ABOVE NORMAL TIDE LEVELS... AND UP TO 17 FEET AT THE HEADS OF BAYS...IS POSSIBLE IN THE WARNED AREA AND WILL BE ACCOMPANIED BY LARGE AND DANGEROUS BATTERING WAVES.

 

FLOODING RAINS OF 15 TO 25 INCHES...WITH LOCALLY HIGHER AMOUNTS ARE LIKELY IN ASSOCIATION WITH THIS SLOW-MOVING HURRICANE.

 

ISOLATED TORNADOES ARE POSSIBLE EAST AND NORTHEAST OF THE TRACK OF GEORGES.

 

SMALL CRAFT FROM INTRACOASTAL CITY LOUISIANA WESTWARD AND SOUTHWARD ALONG THE COAST OF TEXAS SHOULD REMAIN IN PORT.  SMALL CRAFT ALONG THE WEST COAST OF THE FLORIDA PENINSULA SHOULD REMAIN IN PORT UNTIL WINDS AND SEAS SUBSIDE.

 

REPEATING THE 4 PM CDT POSITION...29.0 N... 88.5 W.  MOVEMENT

TOWARD...NORTHWEST NEAR  8 MPH.  MAXIMUM SUSTAINED WINDS...110 MPH.  MINIMUM CENTRAL PRESSURE... 961 MB.

 

INTERMEDIATE ADVISORIES WILL BE ISSUED BY THE NATIONAL HURRICANE CENTER AT 6 PM CDT AND 8 PM CDT FOLLOWED BY THE NEXT COMPLETE ADVISORY AT 10 PM CDT.

 

GUINEY

 






Even if the hurricane had shifted more to the east there would have been little for us to. 

We had to provide information to local people (e.g., Disaster Preparedness).

METOC was boarded up by Thursday.

 

D, A

 

Georges was off the southeast shore of Louisiana.

It was well-defined on radar.

We could see the eye coming up.

 

OSA

5:00 PM - 8:00 PM

The National Hurricane Center (NHC)  had the wrong track.

They said the eye would go one way, but it ended up hitting Biloxi.

The NHC ended up being  off by about four hours on predicted landfall.

 

D

 

The models had it going every which way after landfall.

(See the model forecasts, below.)

 

OSA

 




They were wrong on where the eye was.

We could see it on radar.

 

D, OSA

 

The center was erratic.

You could see the eye wobble on the GOES loop and the radar loop.

The eye was running in and out and sometimes was defined and sometimes was not.

It was moving slowly and shifting from side to side.

 

OSA

 

Sunday night there was an NHC phone discussion. 

 

OSA

9:00 PM

They were still wrong on where the eye was, but they did say it was erratic.

(See the NHC Bulletin #51, below.)

 

D

 

 

 

 

 

 

 

 

BULLETIN

HURRICANE GEORGESS ADVISORY NUMBER  51

NATIONAL WEATHER SERVICE MIAMI FL

10 PM CDT SUN SEP 27 1998

 

GEORGESS SLOWLY APPROACHING THE CENTRAL GULF COAST.

 

A HURRICANE WARNING REMAINS IN EFFECT FROM MORGAN CITY LOUISIANA TO PANAMA CITY FLORIDA.  A HURRICANE WARNING MEANS THAT HURRICANE CONDITIONS ARE EXPECTED IN THE WARNED AREA WITHIN 24 HOURS. PREPARATIONS TO PROTECT LIFE AND PROPERTY SHOULD BE RUSHED TO COMPLETION.

 

A TROPICAL STORM WARNING AND A HURRICANE WATCH REMAIN IN EFFECT FROM EAST OF PANAMA CITY FLORIDA TO ST. MARKS FLORIDA.  AT 10 PM CDT. THE HURRICANE WATCH IS DISCONTINUED FROM WEST OF MORGAN CITY TO INTRACOASTAL CITY LOUISIANA.

 

AT 10 PM CDT 0300Z.

THE CENTER OF HURRICANE GEORGESS WAS LOCATED NEAR LATITUDE 29.5 NORTH, LONGITUDE  88.6 WEST.  THIS POSITION IS ABOUT 70 MILES SOUTH-SOUTHEAST OF BILOXI MISSISSIPPI AND ABOUT 105 MILES EAST-SOUTHEAST OF NEW ORLEANS LOUISIANA.

 

GEORGESS IS MOVING ERRATICALLY BUT GENERALLY TOWARD THE NORTH

NORTHWEST NEAR  6 MPH.  ON THIS TRACK THE CORE OF THE HURRICANE SHOULD REACH THE COAST LATE MONDAY.  DO NOT FOCUS ON THE PRECISE LOCATION AND TRACK OF THE CENTER.  THE HURRICANES DESTRUCTIVE WINDS, RAIN, AND STORM SURGE COVER A WIDE SWATH.

 

MAXIMUM  SUSTAINED WINDS ARE NEAR 105 MPH 165 KM/HR WITH HIGHER GUSTS.  SOME FLUCTUATIONS IN WIND SPEED ARE LIKELY UNTIL THE CENTER MOVES OVER LAND.

 

HURRICANE FORCE WINDS EXTEND OUTWARD UP TO  45 MILES (75 KM.) FROM THE CENTER, AND TROPICAL STORM FORCE WINDS EXTEND OUTWARD UP TO 175 MILES (280 KM.).  THE NEW ORLEANS WSR-88D RADAR INDICATES THAT HURRICANE FORCE WINDS MAY BE OCCURRING NEAR THE GROUND OVER EXTREME SOUTHERN MISSISSIPPI.  KEESLER AIR FORCE BASE RECENTLY REPORTED A GUST TO 79 MPH.

 

THE LATEST ESTIMATED MINIMUM CENTRAL PRESSURE IS  961 MB. (28.38 INCHES).

 

 

 

 

STORM SURGE FLOODING OF 10 TO 15 FEET ABOVE NORMAL TIDE LEVELS AND UP TO 17 FEET AT THE HEADS OF BAYS IS POSSIBLE IN THE WARNED AREA AND WILL BE ACCOMPANIED BY LARGE AND DANGEROUS BATTERING WAVES.

 

FLOODING RAINS OF 15 TO 25 INCHES WITH LOCALLY HIGHER AMOUNTS ARE LIKELY IN ASSOCIATION WITH THIS SLOW-MOVING HURRICANE.

 

ISOLATED TORNADOES ARE POSSIBLE EAST AND NORTHEAST OF THE TRACK OF GEORGESS.

 

SMALL CRAFT FROM WEST OF MORGAN CITY LOUISIANA WESTWARD AND

SOUTHWARD ALONG THE COAST OF TEXAS SHOULD REMAIN IN PORT.  SMALL CRAFT ALONG THE WEST COAST OF THE FLORIDA PENINSULA SHOULD REMAIN IN PORT UNTIL WINDS AND SEAS SUBSIDE.

 

REPEATING THE 10 PM CDT POSITION 29.5 N., 88.6 W.  MOVEMENT

TOWARD NORTH NORTHWEST NEAR  6 MPH.  MAXIMUM SUSTAINED WINDS

105 MPH.  MINIMUM CENTRAL PRESSURE 961 MB.

 

INTERMEDIATE ADVISORIES WILL BE ISSUED BY THE NATIONAL HURRICANE CENTER AT MIDNIGHT CDT AND 2 AM CDT FOLLOWED BY THE NEXT COMPLETE ADVISORY AT 4 AM CDT MONDAY.

 

LAWRENCE

 

 

 

 

But another factor was when we saw the eye come up.

 

OSA

 

We looked at bouy data every few hours and did our own charts.

See the charts I did at 00Z (below).

 

OSA, A

Midnight




The NHC had it making landfall later on Monday.

 

OSA

 

You can't blame the NHC.

They already had their forecast out and they had to follow it.

So did we.

The NHC could always update every three hours, changing where they put the stor surge watches.

But usually they stick with their hourly forecast.

 

D

 

At 2:00 AM the NHC had it between New Orleans and Biloxi.

 

OSA

2:00 AM

The NHC shifted the track a little to the east out to Gulfport but we were leary about that track.

They were still off.

 

OSA, D

 

It picked up speed right after the NHC conference call, so there was not much they could do.

The hurricane sped up and head straight north.

Based on bouy data, we could tell that it was heading north.

 

OSA, D

 

The NHC had it shifting north-west to Louisiana, more of a westward track.

But we could see it heading due north toward Biloxi.

Still, it hit within the area of their forecast.

 

OSA, D

 

There wasn't much to do except put out a few advisories. for heavy weather--every six hours.

So we watched the radar.

 

A, OSA

 

It made landfall Monday morning September 28 between Biloxi and Ocean Springs.

(See the GOES visible image, the GOES colorized image, the GOES enhanced IR image, the NEXRAD reflectivity image and the NEXRAD

velocity image, below.)

 

OSA

approx. 7:30 AM

As it came to landfall the eye was south of NASP.

 

OSA

 












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