Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 11/29/17
Area Forecast Discussion
National Weather Service Albany NY
1001 PM EST Tue Nov 28 2017
Ahead of an approaching frontal boundary, clouds will
increase tonight, along with a few rain showers across the
Adirondacks. Breezy conditions are expected tomorrow, with a mix of
sun and clouds. High pressure will continue dry conditions for
Thursday, before another cold front brings some showers to the area
for Thursday night into Friday.
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
As of 930 PM EST...Not much change to current forecast as an
area of stratus was sct-bkn across the I84 corridor, southern
Taconics, Berkshires and into portions of Litchfield County
which will continue to lift northeast as low level flow
trajectories veer to a more southerly then southwesterly flow.
Canopy of CI/CS was across the northern 2/3rds of the region
with lower clouds along the frontal zone further upstream. Expecting
a large diversity in the temperatures tonight as where winds
are able to decouple will allow temperatures to dip under
ptcldy- moclr skies while others will be warmer. Upstream radar
mosaic was less than impressive at this time as this will need
to be monitor per the latest HRRR suggesting an increase in
coverage. If temperatures remain at or below freezing when the
precip arrives, could see some wintry mixes. Current thoughts
are the cloud increases and the increasing lower level jet
should allow for these temperatures to moderate for mainly rain
showers. We will continue to monitor.
Prev Disc...Surface high pressure is located east of the region
off the coast of New England. Meanwhile, a cold front is moving
across the central Great Lakes and headed eastward.
At the surface, a south to southwest flow is allowing for
breezy conditions across our area, along with temperatures well
into the 40s. Much milder air is just upstream of the region
over western and central NY and Pennsylvania with temps well
into the 50s and 60s.
As the front approaches for tonight, clouds will eventually
increase over our area, although it may take until later in the
night for the thickest clouds to arrive for the Great Lakes.
Although the clouds won`t thicken until late tonight, temps
won`t fall too quickly this evening thanks to the mild and
persistent southerly wind. Lows should fall into the mid 30s to
low 40s, which will be much milder than last night.
Based off the latest 3km HRRR and NAM guidance, some light rain
showers ahead of the front could move into the western
Adirondacks after 2 AM or so. Any precip would be very light and
both temps aloft and in the boundary layer should be warm enough
for any precip to fall as liquid rainfall. Some showers could
also reach into southern VT towards daybreak, otherwise it
should be dry across the remainder of the area thanks to limited
moisture available with this system.
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH THURSDAY NIGHT/...
The cold front will be crossing the area during the morning
hours from west to east. A few lingering rain showers could end
as snow showers over the highest terrain of the Adirondacks, but
little additional precip is expected across the area on
Wednesday. Behind the boundary, temps aloft will quickly fall,
allowing for good mixing to take place. This should allow for
gusty west to northwest winds, with some gusts over 30 MPH
possible. Skies should clear out, allowing for a mostly sunny
afternoon. Highs will mainly be in the 40s to low 50s, and will
likely occur early in the afternoon.
Another fast moving high pressure area will slide across the
area for Wednesday night into Thursday. This will keep it
continued dry and quiet with mainly clear conditions. Lows on
Wed night will be in the 20s and highs on Thursday will be in
the mid 30s to mid 40s.
Yet another frontal boundary will approach within the
progressive fast flow for Thursday night. This front, however,
will actually tap into some Gulf of Mexico moisture, which the
last few fronts have been unable to do. As a result, showers for
Thursday night look a little more widespread than the last few
fronts. Still, precip doesn`t look excessive, with up to a
quarter of an inch possible. Precip looks mainly just liquid
rain due to warm temps aloft, although its possible that some
high terrain areas could changeover to snow showers before
ending towards Friday morning. Lows will be in the 30s for
.LONG TERM /FRIDAY THROUGH TUESDAY/...
An overall tranquil period of weather expected during the long term
portion of this forecast as we start the last month of 2017
(although it appears to become active after this long term period
ending Monday with a winter like weather arriving toward
We start with a large and expanding area of high pressure from the
central CONUS into the I95 corridor Friday night into Saturday. A
short wave tracking along and just north of the US/Canadian border
is expected to track across the upper Great Lakes through Saturday.
Global models after this point diverge a bit as the ECMWF remains
rather progressive with this feature with limited to no impacts for
the region. The GFS and GGEM offer a little more amplification with
the chance of rain/snow showers mainly to the west of the Hudson
where we will continue with chance PoPs.
Regardless of solution, this aforementioned wave should exit off the
northeast coastline Sunday night as another expanding region of high
pressure is expected into Monday. Tranquil and dry weather is in
the forecast at this time before another pattern change arrives just
after this long term forecast period ends.
Temperatures appear to average above normal with below normal
.AVIATION /03Z WEDNESDAY THROUGH SUNDAY/...
VFR conditions as stratus seen just south and east of KPOU
should remain away from there as occasional CI/CS will stream
across the sky tonight. Cold front upstream approaches and will
bring a period of high end MVFR overnight where a shower or two
could impact KGFL. The main issue overnight will be LLWS as we
will continue to highlight in the TAFs, with the exception of
KALB where magnitudes at the surface should remain in place.
Frontal passage occurs Wednesday morning as winds become west-
northwest with occasional gusts as skies slowly clear through
the afternoon hours.
Wednesday Night: No Operational Impact. NO SIG WX.
Thursday: No Operational Impact. NO SIG WX.
Thursday Night: High Operational Impact. Likely SHRA.
Friday: No Operational Impact. NO SIG WX.
Friday Night: No Operational Impact. NO SIG WX.
Saturday: No Operational Impact. NO SIG WX.
Saturday Night: No Operational Impact. NO SIG WX.
Sunday: Low Operational Impact. Slight Chance of SHRA...SHSN.
A few light rain showers are possible over the Adirondacks
tonight into tomorrow morning, but the remainder of the area
will stay dry. After another dry day on Thursday, More
widespread rain (and high terrain snow) showers look to occur
Thursday night into Friday.
RH values will fall to 50 to 70 percent on Wednesday and then as
low as 35 to 55 percent on Thursday. Northwest winds of 10 to 25
mph are expected on Wednesday, with some locally higher gusts.
Winds will switch to the south and become lighter around 5 to 10
mph for Thursday.
High pressure will allow for dry conditions this evening. There
could be some passing rain showers (possibly ending as wet snow
showers) over the Adirondacks late tonight into tomorrow
morning, but liquid equivalent with be under a tenth of an inch,
with dry conditions elsewhere.
After another dry stretch for Wednesday night into Thursday,
another cold front will bring more widespread rain and high
terrain snow showers to the region for Thursday night into
early Friday. Amounts with this system are also fairly light,
generally a quarter of an inch or less. More dry weather is then
expected for the weekend.
As a result, river and stream levels will generally hold steady
during the week and into the weekend. Temperatures will average
slightly above normal through the remainder of the week.
For details on specific area rivers and lakes, including
observed and forecast river stages and lake elevations, please
visit the Advanced Hydrologic Prediction Service /AHPS/ graphs
on our website.
Area Forecast Discussion
National Weather Service Bismarck ND
850 PM CST Tue Nov 28 2017
Issued at 841 PM CST Tue Nov 28 2017
Expanded the High Wind Watch to include Stark, Billings and Golden
Valley counties with this update for Wedneday morning through
early Wednesday evening. The incoming 00 UTC NAM and 00 UTC RAP
continue the trends of earlier iterations through the evening of
the potential for gusts in excess of 50kts across greater portions
of southwest North Dakota behind the cold front. The strongest
winds are favored in the 21-00 UTC window when isallobaric forcing
is greatest. An expansion of High Wind headlines are possible
further east towards the Missouri River. A Wind Advisory will
likely be needed for greater portions of western and central North
Dakota for Wednesday outside of any potential High Wind Warnings.
UPDATE Issued at 535 PM CST Tue Nov 28 2017
Increased overnight lows into the upper 20s and lower 30s for most
of western and central North Dakota as upper level cloud cover
will continue to increase overnight. The 22 UTC NBM has a good
handle on these cloud trends, and will follow its temperature
forecast for tonight as well. Will continue to evaluate wind
headlines for Wednesday.
.SHORT TERM...(This evening through Wednesday)
Issued at 345 PM CST Tue Nov 28 2017
Main forecast problem in the short term period will be winds.
Will allow the current wind advisory in the northeast CWA to
expire. Focus will then shift to Wednesday. Early in the day
strong low level jet develops and spreads from central into
eastern ND ahead of an approaching upper level trough and
associated surface cold front. Strong 50-60 knot winds are
depicted on GFS/NAM bufkit soundings as low as 1.5 to 2k ft above
the surface over eastern portions of central ND. Strong inversion
initially early in the morning, but will diminish during the
morning hours. Question is will the stronger winds aloft be able
to mix down before strongest winds aloft move east and lighter
winds move in with the approaching cold front.
Farther west, strong west to northwest winds develop behind the
cold front over western ND late morning into early afternoon, and
spread east across the forecast area, reaching the James River
Valley during the evening. Steep lapse rates, strong winds aloft
and pressure fall/rise couplet and strong subsidence line up best
over southwest ND around 21 UTC and quickly spread to the Missouri
River Valley around 00 UTC. Directly behind the strongest Cold
advection is a narrow band of warm advection and mid level forcing
producing a band of showers. The lift can work against the
potential for strong winds, but the showers could aid in forcing
the stronger winds to the surface. There is some concern as
whether all ingredients will line up last for a significant
timeframe, of course unless we see a gust to 58 mph...and that
potential is there given the strength of winds aloft within
current forecast soundings. With uncertainty remaining, we will
continue the High wind watch.
We do expect areas around the watch will eventually end up with a
Wind Advisory, but the areal extent remains in question and will
let the overnight shift take another look to nail things down.
We bumped up temperatures over guidance, especially in the south
central which will see warmest temperatures aloft, ahead of the
front and could see a bump in temperatures with the front, similar
to what happened on Sunday.
.LONG TERM...(Wednesday night through Tuesday)
Issued at 345 PM CST Tue Nov 28 2017
Generally dry and mild weather is expected Through the weekend
under a quasi-zonal upper level flow. Still some uncertainty among
the deterministic models on the evolution of a developing trough
over the western and central U.S. late in the weekend into the
middle of next week. Consensus however still looks on the benign
side as far as precipitation is concerned with southern portion of
an upper trough becoming cut-off and a drier and cooler northern
stream influence over the northern plains Monday and Tuesday of
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 841 PM CST Tue Nov 28 2017
A cold front will enter western North Dakota Wednesday morning,
and move across the state through the day. Strong west to
northwest winds are expected behind the front. Gusts of 30-40kts
are forecast, stronger near 50kts across southwest North Dakota.
Ahead of the cold front, strong southerly winds are forecast
across south central North Dakota and the James River Valley
Wednesday morning with gusts of 25-35 kts. Rain showers and
possible MVFR ceilings are forecast across western and north
central North Dakota Wednesday afternoon and into the evening.
High Wind Watch from Wednesday morning through Wednesday
afternoon for NDZ031>033-040-041-043-044.
Area Forecast Discussion
National Weather Service El Paso Tx/Santa Teresa NM
257 PM MST Tue Nov 28 2017
A fairly active, if only moderately impactful, week of weather in
store for the Borderland. A cold front will drop into the area
overnight tonight from the northeast. This will cool temperatures
about 7 to 10 degrees on Wednesday, though this is still above
normal. An upper low will travel across the Baja and northern
Mexico through Saturday, giving the area periods of partly cloudy
skies. A few thunderstorms are even possible Saturday over
Hudspeth County. Temperatures will remain above normal. More
clouds are likely Sunday through Tuesday as another upper low
from the eastern Pacific moves to Arizona. The some light rain is
possible Monday night and Tuesday, mainly for the mountain areas.
Looks like a relatively active week ahead, though it doesn`t look
like much in the way of significant impacts. Main storm track
remains north of the area but split flow with southern branch will
become active over our area. In the short term, back door front
now extending from a line from just east of Albuquerque-Ruidoso-
Carlsbad and continuing to push west and south. Will have to watch
for stratus/fog development over the Sacs tonight, but HRRR not
too keen on that development. Front should be to Arizona border by
daybreak Wednesday. Expect about 7-10 degrees, which still means
above normal temperatures on Wednesday.
Thursday through the weekend...large upper trough moves in off the
eastern Pacific with the southern split closing off an upper low
over the Baja Peninsula. Resultant southwest flow will create long
fetch of sub tropical moisture and clouds for the CWA. Models blip
out some light QPF, but mainly north of the CWA. Upper low over
northern Chihuahua Saturday. GFS shows decent instability, mostly
over Mexico, but also into west Texas. Put slght chance tstms
Hudspeth Co. Saturday, but will have to watch other areas along
the International border.
Monday through Wednesday...southwest flow aloft with cloudiness
to continue as next Pacific trough moves onshore. GFS and ECMWF
have differed drastically over some the last several runs, but 12Z
series for both models shows a trend for agreeing more. ECMWF
still suggests possible winter storm for the entire area, while
GFS would limit rain/snow mainly to the mountain zones. They are a
bit closer in solution, taking upper low to Arizona Tuesday and
then east of the area by Wednesday night. Path of upper low key as
this determines how much cold air can get into the area. For now
will lean to GFS solution, but this certainly bears watching for
possible winter storm scenario.
Increasing clouds through first few hours of period and becoming
FEW-SCT150-200 BKN200-250 for until 30/00Z. Winds will start out
E to NE at 5-15KTS with some gusts over 25KTS on western mountain
slopes of Franklin and Organ Mts. Winds will start to shift around
to the S to E after 12Z and generally remain AOB 12KTS.
Continued dry conditions are expected for much of the forecast
period with just some light rain possible late Saturday into
Sunday. Temperatures will be cooler than recent days for
forecast period but remain above normal by 5-10 degrees with
southwest flow aloft across region through much of the next week.
Relative humidities will be above 20 percent for period and
winds generally less than 15 mph. Vent rates will remain in
the poor to fair categories.
.PRELIMINARY POINT TEMPS/POPS...
El Paso 41 67 42 70 / 0 0 0 0
Sierra Blanca 37 68 41 68 / 0 0 0 0
Las Cruces 37 65 39 68 / 0 0 0 0
Alamogordo 35 62 39 66 / 0 0 0 0
Cloudcroft 27 50 33 52 / 0 0 0 0
Truth or Consequences 35 63 38 65 / 0 0 0 0
Silver City 35 61 38 66 / 0 0 0 0
Deming 35 65 38 70 / 0 0 0 0
Lordsburg 39 67 39 71 / 0 0 0 0
West El Paso Metro 42 66 43 69 / 0 0 0 0
Dell City 35 64 38 67 / 0 0 0 0
Fort Hancock 39 69 41 72 / 0 0 0 0
Loma Linda 37 63 41 64 / 0 0 0 0
Fabens 39 69 40 71 / 0 0 0 0
Santa Teresa 39 66 39 69 / 0 0 0 0
White Sands HQ 38 64 40 68 / 0 0 0 0
Jornada Range 31 64 37 67 / 0 0 0 0
Hatch 33 65 36 68 / 0 0 0 0
Columbus 38 66 39 70 / 0 0 0 0
Orogrande 39 64 41 68 / 0 0 0 0
Mayhill 27 56 34 56 / 0 0 0 0
Mescalero 28 55 34 57 / 0 0 0 0
Timberon 28 53 34 56 / 0 0 0 0
Winston 29 59 31 61 / 0 0 0 0
Hillsboro 34 63 36 65 / 0 0 0 0
Spaceport 30 63 33 66 / 0 0 0 0
Lake Roberts 28 61 30 64 / 0 0 0 0
Hurley 33 62 36 66 / 0 0 0 0
Cliff 28 66 29 67 / 0 0 0 0
Mule Creek 28 63 31 67 / 0 0 0 0
Faywood 34 62 38 67 / 0 0 0 0
Animas 38 69 38 72 / 0 0 0 0
Hachita 36 67 37 70 / 0 0 0 0
Antelope Wells 37 71 39 72 / 0 0 0 0
Cloverdale 40 68 41 70 / 0 0 0 0
Area Forecast Discussion
National Weather Service Miami FL
927 PM EST Tue Nov 28 2017
Main change this evening is backing off of thunderstorms away from
the coast. With showers around, and the lack of thunderstorms,
chances are low to see lightning develop as the showers move
inland. There is still a slight chance of thunderstorms along the
Atlantic coast and the adjacent waters. However, still can not
rule out an isolated strike in the mainland, but the chances are
low enough to keep out of the forecast this evening as this
evenings sounding does show a cap just above 600mb. Otherwise,
minor tweaks to account for current conditions.
.PREV DISCUSSION... /issued 820 PM EST Tue Nov 28 2017/
Water vapor loop continues to show abundant mid and upper level
moisture streaming across South Florida, originating from a weak
low in the eastern Gulf of Mexico. Meanwhile, low level easterly
flow continues to advect in moisture from the Atlantic. NWS radar
displays increasing shower coverage across the east coast metro
region, with dry conditions further west. Short range models
including the HRRR and WRF prog hit and miss showers to spread
over the eastern portion of the peninsula through the night and
continue into Wednesday morning. Weak instability parameters will
generate a slight chance of embedded thunderstorms with this
activity. In the update, trimmed PoPs back from the west coast
tonight. Otherwise, the other forecast parameters appeared on
PREV DISCUSSION... /issued 700 PM EST Tue Nov 28 2017/
Easterly flow, around high pressure centered well to the north, a
lingering boundary over the area, and an upper level disturbance
are helping to keep chances of rain in the forecast through the
TAF period. Chances for showers will even be better in the morning,
causing -SHRA to be in the forecast for several locations. MVFR
CIGS may also occur under the showers activity. Also, there is a
slight chance of a thunderstorm along the Atlantic coast, but
confidence is too low to mention in the TAFs ATTM.
PREV DISCUSSION... /issued 420 PM EST Tue Nov 28 2017/
At the surface, WPC analysis shows a prominent 1031 mb high over
New England with a cold front draped southward from the midwest to
Texas. Clockwise flow around the surface high has allowed for
brisk easterly winds to filter across South Florida today, mainly
15 to 20 mph, with occasional higher gusts. In the mid and upper
levels, latest water vapor loop displays an enhancement of
moisture pushing across the peninsula from the eastern Gulf.
The sounding this morning recorded 1.56" of PWAT, which is higher
than normal when compared to climo. SB CAPE values were pushing
1000 J/KG, indicating the presence of weak instability. These
factors have led to mostly cloudy conditions with a few passing
showers. Through tonight, short range models prog isolated showers
to continue, especially along the eastern portion of the
peninsula. With weak instability still in place, have continued
the threat of isolated thunderstorms in the latest forecast
package. Light winds and moist conditions over the western
interior will lead to the possibility of patchy fog development
late tonight, though not expecting anything widespread.
Wednesday through this weekend: Easterly flow will prevail on
Wednesday with relatively deep low level moisture still in place.
Instability parameters should be similar to today. Thus,
expecting a chance of showers with a slight chance of
thunderstorms over eastern portions of the peninsula. On Thursday,
a weak front presses southward over our CWA, decreasing moisture
levels, and lessing the chance of precipitation. There will be a
similar trend Friday through this weekend, with drier air
filtering into South Florida from the north or northeast. Maximum
temperatures through the period will be in the low 80s along the
east coast metro, gradually warming to the mid 80s along the west
coast. Naples could experience maximum temps around 5 degrees
warmer than average for this time of year. Beyond Sunday, long
range models differ significantly. The GFS pushes a well defined
cold front southward over our region some time on Monday, while
the ECMWF washes out the front and rebuilds a high. Thus,
confidence of the frontal passage is low at this time.
Easterly flow of around 15 to 20 knots will persist
through this evening, so small craft operators should exercise
caution. The chance of showers will remain elevated through
Wednesday night with a few thunderstorms possible. In general,
seas will be 4 feet or less.
Scattered showers and thunderstorms are expected to develop later
this afternoon and evening, with potential for a few TSRA.
Confidence and timing too uncertain to include for this TAF cycle.
Cigs expected to remain VFR with some periods of MVFR. Winds E 10-
12kt through most of the day with some gust 18 to 20 kt. Winds
diminish after 23Z. Winds will increase tomorrow morning ENE around
10kt. KAPF likely to remain dry and VFR.
Northeast winds will be breezy through Wednesday, leading to an
increase in rip current risk along the Atlantic coast beaches.
Moderate to high risk will likely continue through the rest of the
.PRELIMINARY POINT TEMPS/POPS...
West Palm Beach 72 80 71 79 / 50 50 40 30
Fort Lauderdale 72 81 71 80 / 50 50 40 30
Miami 73 82 72 81 / 50 50 40 20
Naples 69 86 68 84 / 10 20 10 10
Area Forecast Discussion
National Weather Service Mobile AL
957 PM CST Tue Nov 28 2017
.DISCUSSION...See updated information for land areas below.
Decreased temperatures to match up with current trends. Still
expecting some patchy fog development overnight prior to sunrise
mainly along the southwest regions of the forecast area. DJ/17
.PREV DISCUSSION... /issued 604 PM CST Tue Nov 28 2017/
DISCUSSION...Updated for latest aviation discussion below.
Majority VFR conditions expected through the initial part of the
evening and night. Prior to sunrise however some patchy fog will
be possible leading to isolated MVFR conditions with IFR
conditions west of Mobile Bay and along the coast. After sunrise
VFR conditions will continue through the day. DJ/17
PREV DISCUSSION... /issued 342 PM CST Tue Nov 28 2017/
NEAR TERM /Now Through Wednesday/...Upper air analysis today
shows a broad trof of low pressure positioned from the southeast US
to the central Gulf. Upstream, a more well defined southern stream
impulse was moving eastward, approaching the OK/TX Panhandles. At
the surface, a large ridge of high pressure extends from off the New
England states, southwest to the central Gulf coast. This high will
continue to be the dominant weather player going into tonight. The
position of the high along with a gradual increase in boundary layer
moisture favors the potential of late night fog development. High
resolution models of the HRRR and NAM12 support this and indicate
that portions of the area, mainly southwest zones, could see
restrictions to visibility lowering to a mile or less late in the
night. Fog mixes out and visibilities improve not long after sunrise
Wednesday. Plains upper level storm system is progged to move
quickly east across the Mid-South and TN River Valley during the day
Wednesday while also de-amplifying. With this feature passing by to
our north, some increase in clouds possible Wednesday. Rain chances
though, look to remain low. /10
SHORT TERM /Wednesday night Through Friday night/...An upper level
shortwave passing north of the forecast area Wednesday evening will
continue moving eastward and deamplify, followed by a large trough
setting up along the eastern seaboard by midnight Thursday night.
This trough will eventually pass over the western Atlantic on
Friday, while broad upper ridging sets up to our west over the
southern plains. Surface high pressure will dominate the eastern
conus through Wednesday night, while a strong surface trough
across the northern plains advances eastward to the Upper Midwest.
The surface high pressure will move east on Thursday, setting up
a low level return flow and increasing low level moisture across
the forecast area. The strong surface trough will eventually move
across the Great Lakes region on Thursday, with the southern
extent of a weak cold front moving through northern Mississippi
and Alabama, and then across much of the forecast area Thursday
night. Isolated to scattered showers will move slowly from west
to east across the forecast area late Wednesday night through
Thursday ahead of and along the weak cold front. The Equilibrium
Level is expected to only be around 16,000 feet with MLCapes
below 50 J/kg, so will leave mention of thunder out for now. The
cold front is expected to move south of the coast by late Thursday
night, with the precipitation tapering off from west to east. A
few showers may linger across the forecast on Friday as the front
struggles to move south across the northern Gulf of Mexico. /22
LONG TERM /Saturday Through Tuesday/...A large surface high
pressure area in the wake of the front will dominate much of the
eastern conus through the weekend, while the upper ridge of high
pressure over the southern plains moves east over the region into
early next week. A few lingering showers possible southeast of
I-65 Saturday morning will move east, followed by a dry period
through the remainder of the weekend.
The surface high pressure will then move east on Monday and
Tuesday, setting up a low level return flow and increasing low
level moisture once again across the forecast area. Over-running
on the backside of the departing surface high pressure will bring
isolated to low-end scattered showers back into the forecast area
Monday and Tuesday. /22
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Area Forecast Discussion
National Weather Service Tampa Bay Ruskin FL
631 PM EST Tue Nov 28 2017
23Z water vapor and H4 RAP analysis continue to portray a
benign sensible weather pattern across the Florida
peninsula. While the upper level pattern is rather
complex...given a closed upper low spinning over the
northern FL peninsula and another over the south-central
Gulf of Mexico...there simply is not enough available column
moisture (especially for the system directly over Florida)
for these systems to have an substantial impact on the
surface weather. In fact...despite the cooler temperatures
aloft over the northern half of the peninsula today...only a
sct cumulus field was able to develop. Any isolated shower
activity migrating westward across the state this past
afternoon was more related to speed/directional convergence
along the FL east coast with the synoptic low level flow.
Expect any additional shower activity related to this flow
to remain east of our forecast counties through the
overnight and Wednesday morning hours. Therefore, the
forecast is dry...with seasonable temperatures.
The upper low drifts off to the east of Florida on
Wednesday, but since it had basically no impact on our
weather anyway...it is barely going to be missed. The real
story on Wednesday will be the warm temperatures. Many spots
will reach the lower 80s for the afternoon...with a few
middle 80s possible down toward Fort Myers. Locations north
of Brooksville will likely top out around 80, but this is
still quite warm for the very end of November.
Just a few isolated showers/sprinkles during the afternoon
migrating westward across the peninsula into zones south of
I-4. Any shower that does occur will be light and
brief...and most spots will not see any rain.
.AVIATION (29/00Z through 30/06Z)...
Prevailing VFR will continue through the evening hours with
a light east/NE flow. Late overnight MOS guidance suggests
higher potential for a period of MVFR/IFR
cigs...however...none of the ensemble guidance suggests this
potential...and similar conditions last night did not
produce this feature. Therefore, adding in a lower SCT
mention...but keeping CIGS out of the forecast. Prevailing
VFR with an E/NE flow between 8-14 kts continues for
Wednesday. Isolated...mainly light showers can be expected
around KPGD/KFMY/KRSW during the afternoon.
Prev Discussion... /issued 242 PM EST Tue Nov 28 2017/
SHORT TERM (Tonight - Wednesday)...
Weak upper level troughing across the Gulf and Florida of
late will finally shift east into the Atlantic tonight
through Wednesday as surface high pressure from offshore the
mid Atlantic coast extending southwest to the northern Gulf
coast remains in place through the period. A slow increase
in moisture will continue through Wednesday which will
support partly cloudy skies along with some isolated (Pops
20 percent) low topped showers across the south central
interior and southern counties during Wednesday afternoon as
well as some low clouds and patchy fog development over
interior locations during late tonight and into early
Wednesday morning, otherwise dry and warm weather will
prevail. Temperatures will run some 5-10 degrees above
normal tonight through Wednesday with lows tonight in the
lower to mid 60s north, and mid to upper 60s central and
south with daytime highs on Wednesday climbing into the
lower to mid 80s.
LONG TERM (Wednesday night - Tuesday)...
There isn`t much to talk about for the Thursday through next
Tuesday timeframe. One frontal boundary will stall before
reaching our region Thursday night and Friday as the upper-
level support remains far to the north. A vigorous upper-
level impulse will help carve out a trough over the Great
Lakes and New England this weekend, but the progressive
nature of the feature means it moves well out into the
Atlantic by Monday with ridging building back over the state
in its wake. We may see a back-door cold front slide down
the eastern seaboard Sunday night and Monday, possibly
dropping dew points a few degrees, but it will have little
if any impact on temperatures. The 00Z ECMWF run showed a
more significant upper-level trough developing over the
eastern half of the nation with a robust cold front
approaching on Tuesday. It has since abandoned that solution
and is now in good agreement with the GFS and Canadian
models showing continued upper-level ridging over Florida.
The current forecast will have no more than a 2 or 3 degree
temperature difference from one day to the next, with
temperatures running 3 to 5 degrees above normal each day.
Rain chances will remain low, less than 20 percent,
throughout the forecast period.
Surface high pressure from offshore the mid Atlantic coast
and extending southwest to the northern Gulf coast will
maintain a northeast to easterly wind flow over the Gulf
waters tonight through Thursday with a tight enough pressure
gradient supporting some nocturnal easterly surges near
cautionary levels during the late evening and overnight time
periods the next few days, especially over the offshore
waters. Similar to yesterday will again hoist cautionary
headlines for the offshore waters tonight as speeds increase
into the 15 to 20 knot range with the surge. A cold front
will approach the northern Gulf waters late on Thursday
where it will likely wash out through Friday as high
pressure building in over the eastern U.S. bridges across
its remains with a northeast to east wind flow continuing
across the waters into the weekend as high pressure sets up
along the eastern seaboard through the period.
Sufficient low level moisture will keep humidity values
above critical levels through the end of the week with no
fire weather issues expected. Some patchy late night and
early morning fog will continue to be possible over inland
areas the next few days, but no widespread visibility
restrictions are expected at this time.
.Preliminary Point Temps/PoPs...
TPA 67 83 65 80 / 0 10 0 10
FMY 67 84 65 82 / 10 20 0 10
GIF 65 82 63 80 / 0 10 0 10
SRQ 66 80 63 81 / 0 10 0 10
BKV 62 82 60 79 / 0 10 0 10
SPG 66 80 64 78 / 0 10 0 10