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Area forecast discussion 
National Weather Service Tampa Bay Ruskin Florida
313 PM EST Wednesday Mar 4 2015

Short term (tonight through thursday)...deep layer high pressure
ridging from the atl extending across cen Florida continues to dominate
through the short term with dry and warm persisting. Shortwave moving
across the Great Lakes to MS River Valley will break down/suppress the
middle-upper level ridge late tomorrow and bring a cold front into the
state. This boundary will not arrive until after this period. Fog
is really the only issue in the short term as shallow moisture
profiles and ridge axis provide somewhat favorable
conditions...but think some models depiction of the fog south of
I-4 might be overdone given low level srly flow. Will therefore keep fog
wording as patchy in southern areas with Nature Coast favored for more
widespread fog (areas). Srly flow is not climatological favored
direction for widespread dense fog...so no need to issue any desne
fog advisory at this point. Sea fog may develop but more srly flow will
limit potential for it to impact land zones. More on sea fog in
marine section below. Leaned toward warmer mav guidance for lows
and blends for highs which limited highs in 87-88 degree f range in
southern areas Thursday. Either way another warm and well above average day
on tap for Thursday.

Middle/long term (thursday night-wednesday)...
models remain are in pretty good agreement through period. Middle/upper
level ridging will become suppressed south late in the week as a
trough and associated series of shortwaves moves across the eastern
states. A cold front associated with this system will move into the
region Thursday night and Friday with high pressure behind it over
the central U.S. Bridging the boundary and shifting winds to a
northeasterly direction. Clouds and a few showers will accompany and
follow the front and have left the 20 to 40 probability of precipitation during Thursday and
Friday with the best chances across the Nature Coast Thursday night
and across the Nature Coast and interior on Friday.

Over the weekend and into next week an upper level low and some
associated energy will move out of the Desert Southwest and slowly
across the southern U.S. And Gulf of Mexico. At the surface the
remnants of the cold front will remain across the region over the
weekend and into early next week then begin to lift back north by
midweek as low pressure develops over the western Gulf of Mexico.
Therefore...some clouds and the threat of a few showers will
continue each day into early next week.

Temperatures will cool some for Friday and Saturday behind the cold
front...especially across the Nature Coast...then begin to warm as
winds shift to easterly early next week and then southeasterly by
midweek with above normal temperatures returning.

&&

Aviation...
as mentioned in main discussion above...am leaning a bit toward
less pessimistic fog/stratus forecast...especially south of I-4...as srly
flow is not climatology favored for widespread dense fog. That
said..patchy/areas of IFR conditions are certainly possible around
sunrise...again especially north of i4. For now have kept VFR conditions
in forecast in Tampa Bay area sites with mainly MVFR forecasts
otherwise. One exception was IFR conditions shown at pgd (fog
favored location)...but even there the 1sm bcfg forecast is much
less pessimistic than MOS guidance which shows LIFR conditions
around sunrise.

&&

Marine...
dewpoints in the middle-upper 60s suggests cen and northern coastal zones
have a threat to develop sea fog at any moment given SSTs in the
low-middle 60s. Hi-res model fog probabilities show this as
well...but sref is less aggressive than narre and local WRF
ensemble probability for fog. Have adopted a slower sea fog development
trend closer to the sref forecasts...but this still suggests
patchy to areas of sea fog especially developing in northern coastal
zone overnight. Best chance of fog will be from 5 to 40 miles offshore (esp
northern zone) with lower potential for impact in Tampa Bay itself
(although patchy sea fog will be possible in the Bay and cen/southern waters as
well).

&&

Fire weather...
generally moist environment will remain with no real fire weather
concerns as relative humidity values remain well above critical thresholds.
Patchy to areas of fog could provide some smoke management/
visibility challenges in the late night and early morning hours.

&&

Preliminary point temps/pops...
tpa 67 80 66 77 / 0 10 20 30
fmy 66 85 66 83 / 0 0 10 30
gif 66 85 64 78 / 0 10 10 30
srq 65 80 64 79 / 0 10 10 20
bkv 60 82 60 75 / 0 10 30 30
spg 68 81 66 76 / 0 10 20 20

&&

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

$$

Short term/aviation/fire weather...88/gittinger
long term...69/close
marine...88/gittinger
decision support...69/close

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