Scientific Forecaster Discussion
fxus62 ktbw 191129
Area forecast discussion
National Weather Service Tampa Bay Ruskin Florida
629 am EST sun Feb 19 2017
Aviation (12z tafs)...
widespread IFR/LIFR visibilities and ceilings will persist
through the morning hours, gradually improving through 14z.
Thereafter, winds will shift to the northwest through the
afternoon hours, becoming light and variable again tonight.
Areas of fog will be likely again overnight with visibility
impacts at most terminals from 06z to 08z through the end of
the forecast period.
Prev discussion... /issued 318 am EST sun Feb 19 2017/
.Dense fog this morning over the Nature Coast and west
upper low spinning over the Carolinas this morning with
last vort Max producing light showers as it wraps over the
area through this morning. Upper low to exit into the west
Atlantic this afternoon with upper ridging quickly building
from the north Carib through the region tonight through Monday.
Weak western Atlantic high pressure axis over S Florida keeping
light winds and abundant low level moisture in place to
produce significant low clouds and widespread dense fog.
Models keep the most widespread dense fog over c and north zones
and have expanded the dense fog advisory into these areas
while wildfire smoke in southeast Polk to add to the superfog event
where visibilities could be down to near zero.
After this morning benign weather later today and Monday
afternoon with warm and humid sensible conditions, but
expect another foggy overnight period into the Monday
Middle term/long term (monday night-saturday)...
a long wave trough extended aloft the mid-section of the
nation...from the northwest territories of Canada to northeast
Mexico...as a ridge over the northwest Caribbean Sea reached
across the eastern states to Hudson Bay Mon night. At the surface
a low near Lake Winnipeg Canada had a warm front across the upper
Great Lakes and a frontal boundary south through the eastern plains
to Texas. High pressure over Quebec Canada stretched down the eastern
states to Cuba.
These features progressively and generally move east. However...
the southern end of the long wave trough over Mexico cuts off into a
low/ along with a surface reflection/ that a takes southeastward
tack across the Gulf of Mexico. This scoots along the north coast of
Cuba Thu night and Fri...reaching the Bahamas Sat as an intact
system (ecmwf) or a washed out wave (gfs). The Canadian keeps just
a trough/open wave tracking across the Gulf. The high pressure
over the eastern U.S. Settles down and elongates along latitude 30
With the models continuing to take a more southerly Route...from
previous runs...but with some discrepancy between them have maintained
the trend of earlier forecasts but with a southward nudge. Showers move
into the Gulf waters Tue night then spread inland and increase Wed-Thu
to showers and thunderstorms with the greatest coverage down south.
For Fri-Sat showers wind down and exit to the east while a cold front
moves into the west/central Gulf. Temperatures run above normal.
fog and low clouds developing and spreading over the area
this morning with IFR vsbys/cigs already in central
terminals and MVFR or worse in SW airports lasting through
12z-14z. Vrf conditions to return mid to late morning
through the afternoon.
weak high pressure to build into and hold over the region
today through Mon/Tue with generally light easterly winds
and seas. A central Gulf low is expected to form mid week
and move into the southeast Gulf later in the week with increasing
winds, seas and rain chances.
low level moisture to remain high keeping afternoon min
humidity well above 35% through the week while fuels remain
Preliminary point temps/pops...
tpa 79 61 80 63 / 20 0 0 0
fmy 83 61 83 61 / 20 0 0 0
gif 81 58 82 60 / 30 0 0 0
srq 76 59 79 61 / 30 0 0 0
bkv 80 53 82 56 / 10 0 0 0
spg 78 63 79 64 / 30 0 0 0
Florida...dense fog advisory until 9 am EST this morning for coastal
Citrus-coastal Hernando-coastal Hillsborough-coastal
Levy-coastal Pasco-inland Citrus-inland Hernando-
inland Hillsborough-inland Levy-inland Pasco-Pinellas-
Beach hazards statement through this evening for coastal