Daweathablog

Charles E. Roop giving his own forecasts, weather discussions, photos and adventures for the Starkville, MS area, Florida, and beyond.

Thursday, July 22, 2010

Tropical Depression 3 Forms Near the Bahamas

Well, it appears that things kicked up a bit overnight. Invest 97L, the tropical wave that now sits over the southern Bahamas has slightly improved and now the National Hurricane Center says it has a closed circulation. To be considered a tropical cyclone, a storm has to have a closed center of circulation. At 11 a.m. EDT, it was upgraded to Tropical Depression 3.

From looking at satellite imagery this morning, it seems that convection has increased. Also, water vapor loops show that dry air isn't invading the circulation as much as it was. However, the heaviest of the thunderstorms remain to the northeast of the center, which indicates the upper-level low still has some influence on the depression, as it can also be seen on water vapor loops. The shear is expected to decrease as time moves forward.


Source: NOAA

Forecast models seem to track the center of circulation a little more to the south - more in the Florida Keys or even further south. For example, the HWRF (see here) has the storm making landfall in the southern Keys Friday morning with 37-knot winds (42 mph, which is tropical storm force).

With the decrease in wind shear and somewhat better development overnight, there is room for slight intensification today and tonight. However, I do not see this as a high-impact wind and surge system. It will mostly be a rainmaker for south Florida.

IMPACTS AT A GLANCE...

- South Florida should start to see affects from TD #3 as early as tonight.

- The Keys will likely get the strongest winds - around 40 knots according to NHC forecasts, with higher gusts possible.

- To the north (Miami-Dade, et al.), some gusts are possible but mostly rain is the main event from this. HPC QPC products show, at most, an inch of rain in some spots in southeast Florida on Friday. In a three-day period, some places can see 1 to 2 inches of rain in south Florida.

- Gainesville will experience better weather, but rain chances will be above normal Saturday as moisture is expected to be pulled in from the depression.

The ridge to the north should keep this storm to the south and not have too much of an impact on central and north Florida.

Interests in south Florida and the Gulf of Mexico need to keep an eye on TD #3. I'll probably make another blog post tonight.

UPDATE: I forgot to mention that there are watches and warnings in effect. From the NHC:
A TROPICAL STORM WARNING IS IN EFFECT FOR... * CENTRAL AND NORTHWESTERN BAHAMAS * FOR THE FLORIDA EAST COAST FROM GOLDEN BEACH SOUTHWARD INCLUDING THE ENTIRE FLORIDA KEYS AND FLORIDA BAY...AND ALONG THE WEST COAST OF FLORIDA NORTHWARD TO BONITA BEACH  A TROPICAL STORM WATCH IN IN EFFECT FOR... * THE EAST COAST OF FLORIDA NORTH OF GOLDEN BEACH TO JUPITER INLET INCLUDING LAKE OKEECHOBEE

No comments:

Post a Comment