Tropical Storm Marco has rapidly formed in the Bay of Campeche.  Maximum sustained winds are near 65 mph.  This morning Marco was nothing more than a low pressure area.  Now, it has the potential to become a hurricane before making landfall in southern Mexico.  Marco is currently a very small tropical system in the southwestern Gulf of Mexico.  It is much smaller than the tropical storm seen in the Pacific Ocean.

Tropical Storm Marco 10-06-2008

Here is what the NHC thinks about Tropical Storm Marco:

A TIMELY MISSION FROM THE AIR FORCE RESERVE HURRICANE HUNTERS...  
TASKED WITH LITTLE ADVANCE NOTICE...REVEALS THAT THE DEPRESSION  
OVER THE EXTREME SOUTHWESTERN GULF OF MEXICO HAS INTENSIFIED INTO A  
TROPICAL STORM.  PEAK SFMR WINDS WERE 53 KT AND PEAK FLIGHT-LEVEL  
WINDS WERE 61 KT.  THESE DATA SUPPORT AN INITIAL INTENSITY OF  
ABOUT 55 KT.  SINCE THE OCEANIC AND ATMOSPHERIC ENVIRONMENT ARE  
SEEMINGLY FAVORABLE...ADDITIONAL INTENSIFICATION IS SHOWN IN LINE  
WITH THE LATEST SHIPS GUIDANCE.  MARCO COULD BE NEAR HURRICANE  
STRENGTH AS IT APPROACHES THE COAST...AND ACCORDINGLY A HURRICANE  
WATCH HAS BEEN ISSUED FOR A PORTION OF THE GULF COAST OF MEXICO.  
IT SHOULD BE NOTED THAT IF THE CURRENT INTENSIFICATION TREND  
CONTINUES...IT MAY BE NECESSARY TO ISSUE A HURRICANE WARNING LATER  
THIS EVENING.  

INITIAL MOTION...295/9...IS A LITTLE TO THE RIGHT OF THE PREVIOUS  
ESTIMATE.  DYNAMICAL GUIDANCE DOES NOT INDICATE MUCH CHANGE IN  
HEADING OVER THE NEXT 1-2 DAYS DUE TO A PRONOUNCED MID-LEVEL RIDGE  
TO THE NORTH OF MARCO.  THE OFFICIAL FORECAST TRACK IS SHIFTED ONLY  
SLIGHTLY TO RIGHT OF THE PREVIOUS ONE AND IS ROUGHLY IN THE MIDDLE  
OF THE TRACK GUIDANCE SUITE.  

WE THANK THE 53RD WEATHER RECONNAISSANCE SQUADRON FOR THEIR QUICK  
RESPONSE TO OUR SHORT-NOTICE REQUEST TO INVESTIGATE THIS STORM.  

FORECAST POSITIONS AND MAX WINDS  

INITIAL      06/2100Z 19.5N  94.7W    55 KT  
 12HR VT     07/0600Z 20.0N  95.6W    60 KT  
 24HR VT     07/1800Z 20.5N  97.0W    60 KT  
 36HR VT     08/0600Z 21.0N  98.5W    25 KT...INLAND  
 48HR VT     08/1800Z...DISSIPATED 

There is a decent chance that severe thunderstorms this afternoon and evening will produce a couple of tornadoes.  The air mass over TX/OK region is extremely humid.  Furthermore, the winds are strong and turn clockwise with height, so there is plenty of wind shear.  The one inhibiting factor is that the surface temps won’t get too warm today.  Therefore, the thermodynamic environment is not favorable for widespread tornadoes.  The scenario looks similar to early spring systems, lots of shear but little thermo.

Tornado Outlook - 10-06-2008

Nevertheless, the Storm Prediction Center has the OK/TX region bullseyed in a 5% chance for tornadoes.

Here is what the SPC is thinking:

MAIN FEATURE FOR THUNDERSTORM DEVELOPMENT TODAY WILL CONTINUE TO BE
LONGWAVE TROUGH SPREADING EWD INTO THE CENTRAL U.S…WHICH CONSISTS
OF TWO MAIN SHORTWAVE TROUGHS- ONE OVER THE NRN HIGH PLAINS AND
ANOTHER EJECTING NEWD OUT OF THE SRN HIGH PLAINS.  SRN MOST IMPULSE
HAS SUSTAINED CLUSTER OF ELEVATED THUNDERSTORMS ARCING FROM CENTRAL
TX INTO CENTRAL OK/SWRN AND CENTRAL KS OVERNIGHT AHEAD OF PRONOUNCED
MID LEVEL DRY INTRUSION ON WV IMAGERY.  THIS ACTIVITY WILL LIKELY
CONTINUE FOR MUCH OF THE DAY AS SYSTEM EJECTS ACROSS OK/KS/NRN
TX…WHICH WILL LIMIT DESTABILIZATION AHEAD OF ASSOCIATED SURFACE
FRONT/TROUGH FORECAST TO EXTEND N-S INVOF I-35 FROM CENTRAL KS INTO
N-CENTRAL TX BY LATE TODAY.

DESPITE THE LIMITED SURFACE HEATING/DESTABILIZATION WITHIN
RELATIVELY MOIST LOW LEVEL AIR MASS AHEAD OF THIS SYSTEM…VERY
STRONG SHEAR /ESPECIALLY IN THE LOWEST FEW KMS/ SUGGESTS EVEN MODEST
HEATING WILL INCREASE RISK OF ORGANIZED STORMS- INCLUDING LOW-TOPPED
SUPERCELLS BY THE EARLY TO MID AFTERNOON WITH THIS LEADING ACTIVITY.
ADDITIONAL DEVELOPMENT IS POSSIBLE ALONG WRN PERIPHERY OF EARLY DAY
STORMS…NEARER THE FRONT FROM CENTRAL OK INTO TX…AS MODEST
HEATING/INSTABILITY OCCURS WITHIN MID LEVEL DRY SLOT.  FORECAST
SOUNDINGS ACROSS THE REGION INDICATE SFC-1 KM SRH IN EXCESS OF
150-250 M2/S2…WITH EFFECTIVE SHEAR AOA 40 KT.  GIVEN LARGE LOW
LEVEL RH/LOW LCLS AND SIGNIFICANT LOW LEVEL SHEAR…RISK OF A BRIEF
TORNADO AND/OR MARGINALLY SEVERE HAIL WILL ACCOMPANY MORE ROBUST
UPDRAFTS…ESPECIALLY IF A FEW DISCRETE STORMS CAN EVOLVE.  ALTHOUGH
ACTIVITY WILL LIKELY INCREASE IN COVERAGE AND SPREAD EWD THROUGH THE
EVENING…OVERALL SEVERE THREAT IS EXPECTED TO DIMINISH AFTER DARK.