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Tropical weather analysis - June 19, 2013

Posted by: KoritheMan, 03:44 GMT le 20 juin 2013

Barry

Tropical Storm Barry continues to move across the extreme southern Bay of Campeche on path toward a landfall in the Mexican state of Veracruz. As of the latest NHC advisory, the following information was available on the storm:

Wind: 45 mph, with higher gusts
Location: 19.6°N 95.8°W
Movement: W at 6 mph
Pressure: 1005 mb

There is still a little bit of time for Barry to strengthen before landfall, as the cyclone is not expected to move inland until Thursday morning. Although the underlying heat content of the Bay of Campeche is currently not very large, Barry is a small enough tropical cyclone so that upwelling will not be a significant factor despite its steadily decreasing forward motion. The latest run of the LGEM, historically shown to be a reliable model, takes Barry up to 45 kt before landfall, with some of the outlying guidance even suggesting an intensity near 50 kt. I am at the upper end of the intensity consensus given the notoriously positive effect of the Bay of Campeche in spinning up storms. It should be noted that there is a weakness in the western end of the mid-level ridge over the Gulf of Mexico, a phenomenon that appears to be caused by a digging mid- to upper-level trough over Texas and northern Mexico. If Barry moves north of the forecast track and continues to decelerate, it would spend more time over water and could have a narrow window to become a hurricane; this is considered an outlier scenario for now.

Figure 1. Latest infrared satellite image of Tropical Storm Barry. Image credit: NOAA's Satellite Services Division (SSD).

Barry is currently south of a narrow mid-level ridge over the northern Gulf of Mexico, with a westward extension of this ridge into central Texas. The global models maintain this general flow pattern until landfall, which suggests the tropical storm's direction of motion will not change much.

Estimating the location and position of Barry has been an arduous task this evening, to say the least. The circulation is small and was thus not well-resolved by an SSMIS pass just before 0z. The radar site at Alvarado is currently not operational, and there has been no recent scatterometer pass over the cyclone. My best guess is what the National Hurricane Center is saying; that the center is along the south side of an ongoing burst of deep convection, likely the beginnings of a central dense overcast. There could still be some jumps to the north as the convection expands in coverage and intensity.

Barry appears to have slowed down a little more, but once again that is fairly difficult to judge. A slight additional decrease in forward speed, perhaps to as slow as 4 mph, is expected as Barry comes under the influence of the aforementioned mid-level trough, which is already eroding the ridge. A general westward path, however, is still anticipated until the cyclone dissipates in about a day.

The primary threat with Barry continues to be heavy rains of 4 to 8 inches over portions of eastern Mexico, primarily Veracruz. Locally higher amounts may occur. These rains will likely cause flash flooding and mudslides over the next few days.

5-day intensity forecast

INITIAL 06/20 0300Z 40 KT 45 MPH
12H 06/20 1200Z 50 KT 60 MPH...INLAND
24H 06/21 0000Z 30 KT 35 MPH...INLAND
36H 06/21 1200Z 25 KT 30 MPH...INLAND
48H 06/22 0000Z...DISSIPATED

5-day track forecast

Figure 2. My 5-day forecast track for Barry.

NHC storm information

000
WTNT32 KNHC 200238
TCPAT2

BULLETIN
TROPICAL STORM BARRY ADVISORY NUMBER 11
NWS NATIONAL HURRICANE CENTER MIAMI FL AL022013
1000 PM CDT WED JUN 19 2013

...BARRY POISED TO BRING HEAVY RAINS TO SOUTHERN MEXICO...

SUMMARY OF 1000 PM CDT...0300 UTC...INFORMATION
-----------------------------------------------
LOCATION...19.6N 95.8W
ABOUT 40 MI...60 KM NE OF VERACRUZ MEXICO
MAXIMUM SUSTAINED WINDS...45 MPH...75 KM/H
PRESENT MOVEMENT...W OR 270 DEGREES AT 6 MPH...9 KM/H
MINIMUM CENTRAL PRESSURE...1005 MB...29.68 INCHES

WATCHES AND WARNINGS
--------------------
CHANGES WITH THIS ADVISORY...

NONE.

SUMMARY OF WATCHES AND WARNINGS IN EFFECT...

A TROPICAL STORM WARNING IS IN EFFECT FOR...
* PUNTA EL LAGARTO TO TUXPAN MEXICO

FOR STORM INFORMATION SPECIFIC TO YOUR AREA...PLEASE MONITOR
PRODUCTS ISSUED BY YOUR NATIONAL METEOROLOGICAL SERVICE.

DISCUSSION AND 48-HOUR OUTLOOK
------------------------------
AT 1000 PM CDT...0300 UTC...THE CENTER OF TROPICAL STORM BARRY WAS
LOCATED NEAR LATITUDE 19.6 NORTH...LONGITUDE 95.8 WEST. BARRY IS
MOVING TOWARD THE WEST NEAR 6 MPH...9 KM/H. A GENERAL WESTWARD
TRACK WITH A DECREASE IN FORWARD SPEED IS EXPECTED TONIGHT AND
THURSDAY. ON THE FORECAST TRACK...THE CENTER IS FORECAST TO
REACH THE COAST IN THE STATE OF VERACRUZ THURSDAY MORNING.

MAXIMUM SUSTAINED WINDS ARE NEAR 45 MPH...75 KM/H...WITH HIGHER
GUSTS. NO SIGNIFICANT STRENGTHENING IS EXPECTED BEFORE LANDFALL...
AND WEAKENING WILL OCCUR AFTER THE CENTER CROSSES THE COAST ON
THURSDAY.

TROPICAL STORM FORCE WINDS EXTEND OUTWARD UP TO 80 MILES...130 KM
FROM THE CENTER.

THE ESTIMATED MINIMUM CENTRAL PRESSURE IS 1005 MB...29.68 INCHES.

HAZARDS AFFECTING LAND
----------------------
RAINFALL...BARRY IS EXPECTED TO PRODUCE TOTAL RAINFALL ACCUMULATIONS
OF 3 TO 5 INCHES WITH MAXIMUM AMOUNTS OF 10 INCHES ACROSS PORTIONS
OF SOUTHERN MEXICO. THESE RAINS COULD CAUSE LIFE-THREATENING FLASH
FLOODING AND MUD SLIDES...ESPECIALLY IN MOUNTAINOUS AREAS.

WIND...TROPICAL STORM CONDITIONS ARE EXPECTED TO REACH THE COAST
WITHIN THE WARNING AREA OVERNIGHT.

NEXT ADVISORY
-------------
NEXT INTERMEDIATE ADVISORY...100 AM CDT.
NEXT COMPLETE ADVISORY...400 AM CDT.

$$
FORECASTER BROWN

Categories:2013 Atlantic hurricane season Tropical Storm Barry

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Tropical weather analysis - June 18, 2013

Posted by: KoritheMan, 03:21 GMT le 19 juin 2013

Tropical Depression Two

Tropical Depression Two continues to pose a rainfall threat for Mexico. As of the 11:00 PM advisory from the NHC, the following information was available on the cyclone:

Wind: 30 mph, with higher gusts
Location: 18.9°N 92.7°W
Movement: WNW at 12 mph
Pressure: 1007 mb

Some bands of deep convection are redeveloping over the Bay of Campeche to the north of the center, which suggests the system is...

Categories:2013 Atlantic hurricane season Tropical Depression Two

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Tropical weather analysis - June 7, 2013

Posted by: KoritheMan, 07:42 GMT le 07 juin 2013

Andrea

Tropical Storm Andrea made landfall in the Florida Big Bend region just south of Steinhatchee early Thursday evening. At the time of landfall, Andrea was a 55 kt tropical storm. It has since weakened as it's moved overland, and the following information was available on the tropical cyclone on the latest NHC intermediate advisory:

Wind: 45 mph, with higher gusts
Location: 31.3°N 81.7°W
Movement: NE at 19 mph
Pressure: 99...

Categories:2013 Atlantic hurricane season Tropical Storm Andrea Invest 92L

Updated: 07:52 GMT le 07 juin 2013

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Tropical weather analysis - June 6, 2013

Posted by: KoritheMan, 05:30 GMT le 06 juin 2013

Andrea

Tropical Storm Andrea formed in the east-central Gulf of Mexico today from what was previously Invest 91L. As of the latest NHC advisory, pending the upcoming intermediate update, the following information was available on the cyclone:

Wind: 40 mph, with higher gusts
Location: 26.0°N 86.3°W
Movement: N at 6 mph
Pressure: 1002 mb

Andrea is a typical early June tropical cyclone, with much of the associated weath...

Categories:2013 Atlantic hurricane season Tropical Storm Andrea

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Tropical weather analysis - June 5, 2013

Posted by: KoritheMan, 06:15 GMT le 05 juin 2013

Invest 91L

A weak area of low pressure over the central Gulf of Mexico continues to produce widespread disorganized showers and thunderstorms to the east of the low.

Convection continues to wax and wane, with a current burst going off about two degrees east of the estimated center location. However, CIMSS analyses diagnoses about 25 kt of westerly shear over the disturbance, which in combination with a very subsident airmass over the western Gulf of Me...

Categories:2013 Atlantic hurricane season

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