Monday, September 28, 2015

Tropical Storm Joaquin

Wednesday 9/30/2015 11:00PM  Update:
11:00PM advisory out. No change to track, max intensity adjusted up to 140mph, Category 4. 
 From the NHC:
...JOAQUIN BECOMES A CATEGORY 3 HURRICANE AS IT MOVES TOWARD THE CENTRAL BAHAMAS...
11:00 PM EDT Wed Sep 30
Location: 23.8N 73.1W
Moving: SW at 6 mph
Min pressure: 951 mb
Max sustained: 115 mph 

Wednesday 9/30/2015 10:00PM  Update:
Joaquin has been upgraded to a Hurricane and is currently impacting the Bahamas. It is currently rapidly intensifying. At 8:00 PM EDT, the NHC increased sustained winds to 105 mph (Category 2), about 10mph from major hurricane status. The ongoing Hurricane Hunter Mission has estimated winds over Category 3 strength. As a result, we expect the NHC to upgrade Joaquin to a major hurricane at 11:00PM EDT. Joaquin is currently meandering SSW near the Bahamas and has just recently popped out an eye. The NHC track brings it northwards on Friday and landfalls in SE Virginia late Saturday. This track should be shifted SW to reflect model consensus next advisory (11:00PM)
Models today have continued to trend southwards, with a landfall clustered around central North Carolina. That being said, there is still a lot of model spread. The European model, which is one of the best in the world, brings it out to sea. However, most models bend it into the East Coast.

To hopefully increase forecast consensus and accuracy, special weather balloon launches as well as hurricane hunter and other reconnaissance aircraft data will be inputted into the next model runs. We will be eagerly awaiting them. The bottom line is we are still not out of the woods. Even with a NC landfall, we could experience gusts up to 60 mph as well as heavy rain over the weekend into next week. Also, the storm could just as easily sift farther north. Until Joaquin begins it's northward turn, anything can happen.


Tuesday 9/29/2015 6:00PM  Update:
TS Joaquin broke a model...SENIOR DUTY METEOROLOGIST NWS ADMINISTRATIVE MESSAGE
NWS NCEP CENTRAL OPERATIONS COLLEGE PARK MD
2256Z TUE SEP 29 2015


18Z NAM UPDATE...

THE 18Z NAM FORECAST HAS PROGRESSED...GENERATING PRODUCTS OUT TO
T+57 BEFORE FAILING AGAIN. OUR TECH SUPPORT, ALONG WITH THE
MODEL DEVELOPER, BELIEVES THE ISSUE IS DUE TO HOW THE MODEL IS
HANDLING WATER TEMPERATURE NEAR TS JOAQUIN. THEY ARE CONTINUING
TO WORK TOWARDS A RESOLUTION ON THIS ISSUE. WE WILL KEEP YOU
POSTED. THANK YOU FOR YOUR PATIENCE.


Tuesday 9/29/2015 5:00PM  Update:
Well that was fast. Tropical Storm Joaquin has begun strengthening relatively quickly. This afternoon, the Hurricane Hunters measured a central pressure of 990mb and sustained winds up to 65 mph. Its cloud structure has improved since last night with deep convection covering the center of circulation although most of the convection is still confined to the south side of the storm due to persistent northwesterly shear.
The Future:
Tropical Storm Joaquin is expected to meander southwest for the next few days before turning northward as the upper level low out over the central US shifts eastward.

Monday 9/28/2015 Original Text:
Satellite imagery shows deep convection  with good outflow to the south. The Bahamas is on the bottom left
Tropical Depression 11, named last night, has sufficiently organized to be upgraded to Tropical Storm Joaquin.

Forecast Model runs (Dynamical+Statistical Early Cycle Models)
Official Track
Slow strengthening is forecast as it moves WSW towards the Bahamas before turning NNWwards towards the East Coast in response to a trough. Forecast models are still all over the place so the track is very uncertain. Stay alert for possible heavy rain and gusty winds this weekend.