Thread: Invest 90L - Yes in FEBRUARY!

000
abnt20 knhc 052346
twoat

special tropical weather outlook
nws national hurricane center miami fl
645 pm est sun feb 5 2012

for the north atlantic...caribbean sea and the gulf of mexico...

A non-tropical low pressure system interacting with an upper-level
trough is producing widespread cloudiness...showers...and scattered
thunderstorms across much of western and central cuba...the lower
florida keys...and adjacent waters of the northwestern caribbean
sea...southeastern gulf of mexico...and the florida straits. The
low is centered just west of the western tip of cuba...and a
surface circulation center is gradually becoming better defined.
Shower activity has been slowly increasing and has become better
organized today...and if this development trend continues...then a
subtropical depression or a subtropical storm could form during
the next day or so before the disturbance merges with a cold front.
This system has a medium chance...30 percent...of becoming a
subtropical cyclone during the next 48 hours as it moves slowly
north-northeastward tonight and monday morning...before turning
northeastward at 10 to 15 mph toward south florida and the florida
keys by monday afternoon and evening. Regardless of development...
This system will likely bring locally heavy rainfall and strong
gusty winds to portions of the florida keys and south florida over
the next couple of days. Additional information on this system can
be found in offshore waters forecasts issued by the national weather
service...under awips header miaoffnt3 and wmo header fznt24
knhc...and also in products issued by your local national weather
service forecast office. Additional special tropical weather
outlooks will be issued as needed.

Elsewhere...tropical cyclone formation is not expected during the
next 48 hours.


$$
forecaster stewart

There is only a slight chance this will develop, and if it does, it would be subtropical.

This happened just once before - in the 1950's, I believe. I will see if I can verify that, as I am not positive.

It may mean some rain for S and SW Florida.... nothing menacing in all likelihood

Found the answer, thanks to Dr. Jeff Masters. It was on Groundhog Day, 1952.

Here is an excerpt from his blog for today:

OK, this is officially nuts. The first Super Sunday Invest in history formed this morning . . . and is slowly becoming more organized as it moves northeast towards Southwest Florida. The new disturbance . . . has a modest but growing area of heavy thunderstorms near its center. Visible satellite imagery shows a pronounced spin at middle levels of the atmosphere, and 90L may be able to close off a surface circulation if it can find 24 more hours of marginally favorable conditions.


http://www.wunderground.com/blog/Jef...?entrynum=2028

Regarding the precedent, he says -

The 1952 Groundhog Day Storm was the only Atlantic tropical cyclone on record in the month of February. . . . it moved rapidly throughout its duration and struck southwestern Florida within 24 hours . . . . winds damaged some crops and power lines, but no serious damage was reported.

...special feature...
An area of disturbed weather is bringing heavy rainfall across
wrn cuba and the se gulf of mexico tonight. A surface trough is
analyzed through the yucatan channel along 25n87w 22n86w 20n85w
with a 1012 mb low along the axis near 22n87w...as of 2100 utc.
The system is supported by a shortwave upper trough along 24n89w
to 18n83w which is providing an area of diffluence aloft across
wrn cuba and the se gulf where the shower/thunderstorm activity
is located. Currently showers/thunderstorms extend from 19n-25n
between 77w-88w. Areas in wrn cuba have already reported up to
an inch of rain over the past 24 hours. The system is expected
to move ne which will continue to bring rain to wrn cuba and
will begin to move the moisture towards s florida. Local
forecasts indicate up to 2 inches of rain is expected across
portions of s florida. Interests in cuba...the se gulf of
mexico...and s florida should monitor the progress of the
system.

Yup. On the SW coast of Florida we are expecting scattered rain & thunderstorms tomorrow. Not expected to be severe. Worst weather will be the SE and north Florida east coast and inland a bit. Even tho it is subtropical the winds & storms could cause some damage to crops & small trees.

Very unusual, and of interest because of that. Our local on air met can't stop talking about it. He is just fascinated with it.