Scientific Forecaster Discussion

Return to Local Conditions & Forecast

Without Abbreviations
With Abbreviations

Area forecast discussion...updated 
National Weather Service Tampa Bay Ruskin Florida
1025 PM EDT Thursday Mar 26 2015

main issue for tafs was timing of precipitation/thunderstorms and potential for
MVFR ceilings. Following scenario below in previous discussion...
leaning toward thunderstorms impacts sites late tonight and again Friday with
2 separate thunderstorm events. Widespread precipitation and frontal passage Friday will
provide high probability of MVFR ceilings much of the day on Friday and
on and off MVFR ceilings are also possible tonight. Winds will turn west
and northwest through day and increase with gusts in the 20s. Some strong
storms are possible.


prefrontal showers currently moving across the northern and
central waters. Most of the activity is far behind these showers
as the front is still lagging back near New Orleans. The front
will approach overnight and sweep the coastal waters Friday with
winds veering to northwest at caution to advisory speeds. High
pressure builds in over the weekend with winds veering and
diminishing into early next week.


Previous discussion... /issued 957 PM EDT Thursday Mar 26 2015/

Update...first convective event associated west/ approaching upper trough
is winding down with just a few rain showers along the outflow boundary
across cen zones. Big challenge tonight is timing and charactor
of next convective event as models struggle with storms which are
developing along outflows...the prefrontal trough...etc. Most
global models and some high res models including most recent local
WRF run are focusing on a Friday daytime event with the main focus
being either a prefrontal trough or the actual front. That
scenario would provide the greatest the severe threat with this
upper trough and associated front as the convective timing would line up
with best upper support and greatest shear. That said...a cluster of
storms well offshore in the Gomex south of New Orleans to tlh is
tracking east-southeast at pretty good clip and if it holds together it
will arrive by around 7z. This will not preclude an additional
convective event later on Friday with main upper dynamics and
front...but could significantly hamper instability and severe
potential during the day. Even so...there is enough shear
overnight that there is a very low probability of severe storms
with this activity overnight and somewhat average looking storms
produced 45 miles per hour earlier this evening. Given all the
uncertainty...Storm Prediction Center has maintained a marginal risk of severe storms
tonight across northern half and tomorrow across across our southern half.
Gonna have to let this play out a little but feel the second
scenario above is most likely to occur (storms tonight and again
tomorrow). This of course still means high probability of precipitation and decent
rainfall amounts are in order tonight and Friday. Have and will
continue to tweak grid timing based on this thinking.


Preliminary point temps/pops...
tpa 72 77 55 69 / 70 80 0 0
fmy 72 81 58 75 / 60 90 10 0
gif 69 79 52 70 / 50 80 0 0
srq 71 77 57 69 / 60 80 0 0
bkv 68 77 47 68 / 80 90 10 0
spg 72 76 59 68 / 70 80 0 0


Tbw watches/warnings/advisories...
Gulf waters...none.


decision support...99

National Weather Service Glossary of Abbreviations