042
WTNT42 KNHC 211457
TCDAT2
TROPICAL STORM BERTHA DISCUSSION NUMBER 9
NWS NATIONAL HURRICANE CENTER MIAMI FL AL022026
1000 AM CDT TUE JUL 21 2026
BERTHA HAS BECOME SLIGHTLY BETTER ORGANIZED THIS MORNING. WHILE THE
LOW-LEVEL CENTER WAS FULLY EXPOSED OVERNIGHT, NEW DEEP CONVECTION
HAS DEVELOPED THIS MORNING AND THE CENTER HAS BECOME AT LEAST
PARTIALLY TUCKED UNDERNEATH THE COLD OVERCAST. THE AIR FORCE
HURRICANE HUNTERS HAVE BEEN INVESTIGATING THE STORM, AND THEY
REPORTED PEAK 850-MB FLIGHT-LEVEL WINDS OF 62 KT WITHIN THE
CONVECTION TO THE SOUTHEAST OF THE CENTER, ALONG WITH LAYER-AVERAGED
DROPSONDE WINDS THAT SUPPORT RAISING THE INITIAL INTENSITY TO 50 KT.
THE CENTRAL PRESSURE HAS FALLEN SLIGHTLY TO 995 MB.
BERTHA HAS DEVIATED NORTH OF THE FORECAST TRACK DURING THE PAST
SEVERAL HOURS, AND THE INITIAL MOTION IS NORTH-NORTHWESTWARD (345/3
KT). THE NEAR-TERM TRACK FORECAST HAS BEEN ADJUSTED NORTHWARD TO
ACCOUNT FOR THIS DEVELOPMENT. WHILE BERTHA IS CURRENTLY IN FAIRLY
WEAK STEERING CURRENTS, A MID-LEVEL RIDGE CENTERED NEAR THE ROCKIES
IS EXPECTED TO MOVE SOUTHEASTWARD DURING THE NEXT COUPLE OF DAYS.
THIS SHOULD CAUSE BERTHA TO TURN MORE WEST-NORTHWESTWARD AND THEN
WESTWARD WHILE IT MOVES NEAR OR ALONG THE NORTHERN GULF COAST
THROUGH MIDWEEK. WHILE THE TRACK MODELS ARE OVERALL IN GOOD
AGREEMENT ON THIS SCENARIO, THERE ARE DIFFERENCES IN HOW MUCH LAND
INTERACTION WITH SOUTHEASTERN LOUISIANA WILL OCCUR, AND WHETHER A
NEW CENTER MAY REDEVELOP OFF THE COAST. LITTLE CHANGE WAS MADE TO
THE NHC TRACK FORECAST BEYOND 24 H, AND ONCE AGAIN THIS FORECAST
ASSUMES BERTHA IS ABLE TO MAINTAIN A COHESIVE CIRCULATION AS IT
PASSES NEAR OR OVER THE NORTHERN GULF COAST.
BERTHA REMAINS AN ASYMMETRIC TROPICAL STORM, WITH MOST OF THE
RAINFALL AND THE STRONGEST WINDS OCCURRING TO THE SOUTH AND EAST OF
THE CENTER. STRONG NORTHEASTERLY VERTICAL WIND SHEAR OVER BERTHA IS
FORECAST TO PERSIST TODAY AND TONIGHT, WHICH SHOULD MAKE IT
DIFFICULT FOR BERTHA TO STRENGTHEN MUCH MORE. CONVECTION IS EXPECTED
TO CONTINUE PULSING TO THE SOUTH OF BERTHA'S CENTER DURING THIS
TIME, AND THE NHC FORECAST OVERALL SHOWS GRADUAL WEAKENING OVER THE
NEXT FEW DAYS. THE EXTENT OF THIS WEAKENING WILL DEPEND ON HOW MUCH
LAND INTERACTION OCCURS DURING THE NEXT COUPLE OF DAYS, AND IT
REMAINS POSSIBLE THAT BERTHA COULD DEGENERATE INTO A TROUGH EVEN
SOONER THAN FORECAST DUE TO A DISRUPTED STRUCTURE WITHIN HOSTILE
ENVIRONMENTAL CONDITIONS.
SOME NOTABLE WATCH/WARNING CHANGES WERE MADE WITH THIS ADVISORY
PACKAGE. THE TROPICAL STORM WARNING WAS EXTENDED EASTWARD ACROSS
THE FLORIDA PANHANDLE AND WESTWARD TO THE TERREBONNE/LAFOURCHE
PARISH LINE IN LOUISIANA. IN ADDITION, THE STORM SURGE WATCH HAS
BEEN REPLACED WITH A COASTAL FLOOD WARNING ISSUED BY THE LOCAL
FORECAST OFFICE. MINOR TO MODERATE COASTAL FLOODING IS STILL
EXPECTED TO OCCUR BETWEEN THE MISSISSIPPI/ALABAMA BORDER AND THE
MOUTH OF THE MISSISSIPPI RIVER, WITH PEAK VALUES UP TO 4 FT ABOVE
GROUND LEVEL.
KEY MESSAGES:
1. BERTHA IS EXPECTED TO BRING TROPICAL STORM CONDITIONS TO PORTIONS
OF THE GULF COAST FROM THE FLORIDA PANHANDLE WESTWARD TO
SOUTHEASTERN LOUISIANA LATER TODAY AND WEDNESDAY, WHERE A TROPICAL
STORM WARNING IS IN EFFECT. TROPICAL STORM CONDITIONS ARE POSSIBLE
FOR METRO NEW ORLEANS AND THE SOUTHERN GULF COAST OF LOUISIANA,
WHERE A TROPICAL STORM WATCH IS IN EFFECT.
2. A COASTAL FLOOD WARNING IS IN EFFECT FOR THE MISSISSIPPI AND
LOUISIANA COASTLINES, WHERE MODERATE COASTAL FLOODING IS EXPECTED.
3. INTERESTS ELSEWHERE IN LOUISIANA AND TEXAS SHOULD MONITOR THE
PROGRESS OF THIS SYSTEM, AS ADDITIONAL WATCHES OR WARNINGS COULD BE
REQUIRED FOR PORTIONS OF THAT AREA.
4. ISOLATED AREAS OF FLASH FLOODING WILL BE POSSIBLE THROUGH FRIDAY
ALONG THE GULF COAST FROM WESTERN FLORIDA INTO SOUTHERN LOUISIANA
AND THE UPPER TEXAS COAST.
FORECAST POSITIONS AND MAX WINDS
INIT 21/1500Z 29.3N 86.3W 50 KT 60 MPH
12H 22/0000Z 29.4N 87.0W 50 KT 60 MPH
24H 22/1200Z 29.5N 88.0W 45 KT 50 MPH
36H 23/0000Z 29.4N 89.5W 40 KT 45 MPH...NEAR THE COAST
48H 23/1200Z 29.3N 91.3W 35 KT 40 MPH...NEAR THE COAST
60H 24/0000Z 29.4N 93.1W 30 KT 35 MPH...OVER WATER
72H 24/1200Z 29.9N 94.9W 25 KT 30 MPH...INLAND
96H 25/1200Z 31.0N 97.5W 20 KT 25 MPH...POST-TROP/INLAND
120H 26/1200Z...DISSIPATED
FORECASTER REINHART
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