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450
fxus62 kmfl 180855
afdmfl
area forecast discussion
national weather service miami fl
455 am edt mon may 18 2009
discussion
a fairly impressive late season cold front currently
stretches from the central gulf of mexico, across the fl
panhandle, and then northeastward along the coast of the
carolinas. The inverted trough that past s fl a few nights ago
remains stretched across the west gulf while another trough
remains across western cuba. In the mid and upper levels... A
vigorous short wave continues to carve into the gulf while a mid
level low is pushing n-nw across west cuba.
The aforementioned systems have set up a very complicated and
difficult forecast with plenty of variables... We'll start with the
cold front. The front is expected to move south through today and
enter the lake region late this afternoon... It may even continue
on this evening and make it to far south florida by midnight or a
little after before putting on the brakes. While the front moves into s
fl the short wave pushing into the gulf will provide plenty of
divergence aloft/large scale ascent to allow widespread shower and
thunderstorm activity. The only limiting factor will be the amount
of heating today is in question, so kept chance of thunder instead
of widespread or likely. Also... While this is ongoing deep
tropical moisture from the southeast will begin to filter into the
area as the mid level and surface trough over west cuba move nw.
All of this will combine to possibly produce heavy rainfall
especially around the frontal boundary where the best lift will be
found. An isold severe tsra also can not be ruled out this
afternoon, especially if skies remain clear and temps warm into
the upper 80s to near 90 over the interior. Then as early as
tonight the forecast begins to become fuzzy... A weak low may
develop either from the trough near west cuba or from the cold
front/trough over the gulf combo. The gfs likes the trough near
cuba and lifts it through the bahamas, but then pushes it back to
s fl late in the week as the south end of the short wave cuts off
and retrogrades back west. The ecmwf and 6z nam tend to like the
western solution. If the gfs is correct then precip may be less or
at least delayed more than currently anticipated, but on the other
hand the nam and euro keep s fl wet for a while. The 0z nam and
ukmet also liked the trough over west cuba but took the low
across the cwa... Which is basically in the middle of all the
solutions... So stuck with the middle... And so has tafb...
However it should be noted that confidence is very low on the
evolution/track of this system and a deviation of just 100 miles
will mean widespread rain or isold shra for the area tuesday and
tues night and into wednesday. By the end of week and into the weekend
trended the forecast down to climo values as the surface low
supposedly lifts out.
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