SEP 26, 2005 / 11:45 AM
REMNANTS OF RITA HEAD FOR GULF COAST
TROPICAL WAVE CARIBBEAN MAY BECOME DEPRESSION WITHIN NEXT 24 HOURS
AND STORM INTO GULF OF MEXICO BY END OF WEEK
Though still showing only a weak reflection in the mandatory level charts, the remnants of RITA, currently
embedded within a much larger upper level TROF are clearly moving southeast towards the Florida Panhandle
as evidenced on Radar. (see Below)
The GFS shows the system moving into the Gulf and developing some -- but there does not yet seem to be the
type of upper level support it would need to truly re-generate into a tropical storm. However, what isn't in Rita's favor
is quickly becoming in favor for a strong Tropical wave moving fairly quickly through the central Caribbean now,
and is showing some signs of better organization, with some slight but significant surface pressure falls in the
central Caribbean.
As mentioned yesterday evening, there are 2 large upper air TROFS from the central Atlantic extending
southwestward into the tropics. One is to the east of the developing Wave, on is to the west, over the far
NW Caribbean. Between the 2 systems, we end up with an generally anticyclonic flow, which favors
outflow aloft. What appears to be happening based on water vapor loop imagery is the formation of
a closed low aloft over the western Bahamas north of Cuba, while at the same time, there may be a
simultaneous developing of a high pressure system above the developing wave - and this is
crucial - independent of the larger scale antic-cyclonic flow across the tropical wave that is
occurring between the 2 major upper level TROFS. If there is a developing anti-cyclone within the waves
own circulation field, then the system will likely develop into a tropical cyclone during the next 24 hours.
On the latest Visible image loop there are hints of a broad low level circulation trying to form near 14N/73W.
In general the entire disturbance is heading WNW at 15Kts, and will likely be about 100-200 miles south of
Jamaica by Tuesday morning assuming it does in fact develop by then into a a tropical depression.
As it moves northwest - towards the far NW Caribbean and Yucatan Channel by Thursday -- conditions
aloft are forecast to become more favorable for development, and a we could have the next tropical storm
of the season by that that time. The speed of development will depend a lot on whether the system is in
fact developing it's own upper level outflow pattern.
The next update on this system - and if need be, the remnants of Rita, will be tomorrow morning - unless
conditions warrant an update earlier. IOW - if the system system develops into a a tropical depression
sooner rather than later)
Steve
Steve Gregory
WeatherInsite
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PIX 1 - The remnants of RITA - 'hidden' with an upper level TROF in the form of a strong VORT Max, is
heading southeastward into the Florida Panhandle, and has in fact broken away from the bulk of it moisture and upper
level circulation field that got pulled to the northeast yesterday. The GFS does show this system moving into the Gulf
and re-generating. This is VERY similar to IVAN - and if it actually happens, NHC gets o decide if the evidence supports
calling it RITA, or making it a new system. The evidence to me - IF IT EVEN HAPPENS -0 is clearly this is Rita.
But overall, the system coming from the Caribbean will dominate the broader circulation field, and I don't think at this time,
Rita will attain Tropical Storm intensity before the Caribbean system starts to over power whatever is left of Rita.
This mornings VIS imagery shows a TINY bit of banding and low level circulation trying to develop within the strong tropical wave.
Microwave analysis (not shown) indicates there arte some curved bands of strong and deep convection around this system, though
NOT yet organized enough to call this a depression.
Water Vapor image shows 2 main areas of heavy convection with the Tropical Wave. But based on the microwave
and VIS images -- the westerner area of convection is closest to the circulation field that is trying to
form near 14N/73W. The upper level TROFS are the elongated areas of DRY air along 50W
and 40N/60W down to 22N/63W -- with the new development of a closed upper cyclonic low located
between SE Florida and the Cuban coast. The net result is a an anticyclonic flow aloft over
the Tropical Wave, that does seem to be developing it's own upper level anti-cyclone system.
The outflow itself is good in the WNW quadrant and to the southwest - but is hindered in the eastern semicircle. HOWEVER,
note carefully that there is now a closed anticyclone feature centered just north and east of Puerto Rico. If this displaced
outflow center manages to get vertically aligned with the wave, a tropical cyclone will likely form. That upper low
north of Cuba - if it continues drifting westward, actually is enhancing the outflow channel trying to
developing in the northwest quadrant of the wave.
At the moment, shear values remain high 12-14 Kts. But this could drop significantly
during the next 24-48 hours if the anticyclone center near Puerto Rico either aligns
itself with the lower level wave, or if the developing wave manages to develop it's own outflow
center at high levels.
The 12Z model runs -- very few were run for this system -- though if it continues to develop, this evening
we will se the normal complement of models show the system tracking northwestward - with 22 models
moving it towards the northwest Caribbean, and 3 others, over Jamaica in 36 hours (early Tuesday evening).
As the system is still very shallow, I prefer the BAMS and CLP5 models that keep the system south of Jamaica.
Either way, a period of heavy, gusty showers and squalls will buffet the Island on Tuesday. Conditions to
not seem favorable enough yet for rapid development, and the system should not attain Tropical Storm force
until it passes by Jamaica itself.
The few intensity forecasts available to bring the system up to hurricane intensity in 3 -4 days.
If this happens, and the system reaches the Yucatan Channel -- the Gulf of Mexico will
once again have a storm to deal with.