Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 03/22/17
Area Forecast Discussion
National Weather Service Columbia SC
723 PM EDT Tue Mar 21 2017
.SYNOPSIS...
A cold front approaching from the north will slowly cross the
forecast area overnight. Numerous showers and thunderstorms are
expected head of the front. Very warm temperatures this
afternoon will be followed by cooler temperatures behind the
front.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
Regional radars currently showing strong thunderstorms in the
upstate of both SC and GA this evening. This activity has been
relatively stationary, with a the storms having difficulty
pushing eastward into a capping inversion currently over central
portions of SC. This inversion will weaken as the evening
progresses, and the activity is expected to eventually begin
tracking eastward. This will be in advance of a MCS that is
moving into eastern TN this evening, and this MCS is expected to
rapidly push eastward across northern GA and into
northern/central SC, and eastern GS by midnight. As this MCS
catches up with the current convection across the upstate,
expect to see the entire complex push east/southeastward through
much of the cwa. This continues to be supported by the latest
hrrr guidance. The main threats will be damaging winds, large
hail, and even some heavy rainfall in the slower moving,
possible training, storms.
The high-resolution models have trended slower with the timing.
The latest HRRR is still indicating some isolated to scattered
convection possible between 8 pm and 11 pm, the the most
widespread shower and thunderstorm coverage by midnight. The
more intense convection shifts east of the area by 200 am, with
mainly some stratiform rainfall in its wake.
The front should shift south of the area after 400 am. There may
be lingering showers in the area. Followed the guidance consensus
for the temperature forecast overnight.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH THURSDAY NIGHT/...
The cold front will be moving south of the area Wednesday
morning with high pressure centered over the western Great Lakes
region building in behind it. Clouds are expected to linger,
but precipitation should be south of the area so have lowered
pops. Highs on Wednesday are forecast in the middle 60s to lower
70s. The center of high pressure will move into the Delmarva
region on Thursday and ridge into the forecast area from the
northeast. Models have trended drier with pops on Thursday.
Extensive cloud cover should result in temperatures well below
normal on Thursday, but confidence low regarding exactly how low
temperatures will be given model differences.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
An upper ridge will be centered over the southeastern US on
Friday and will push off the coast on Saturday as an upper
trough over the Plains lifts northeastward. Surface high
pressure will be off the coast on Friday and will continue to
ridge into the area from the northeast with dry weather
expected. Temperatures will rebound on Friday back into the
middle 60s to lower 70s under the influence of the ridge. A low
pressure system over the southern Plains will shift northeastward
toward the southern Great Lakes region on Saturday and bring a
front into the area on Sunday. The frontal boundary will linger
in the area on Monday and remain near the area on Tuesday.
Temperatures over the weekend and into Tuesday above normal.
&&
.AVIATION /00Z TUESDAY THROUGH SUNDAY/...
VFR conditions will continue for the next couple hours, but then
MVFR ceilings are likely as strong thunderstorms move into the
area. There will also be periods of IFR conditions in heavy rain,
but too difficult to time. Storms could develop over KAGS and
KDNL as early as 01Z. Upstream convection is expected to move
over CAE and CUB around 02Z, and then OGB. Timing is based on
HRRR, but these storms have so far been moving very slowly, and
arrival could actually be later. Strong heating ahead of the
front and very cold air aloft support the potential for damaging
wind and large hail with any thunderstorms.
There should be a diminished threat of severe weather after 05Z
because of previous convection and nocturnal cooling. The front
should shift south of the area after 09Z, and skies should
clear by 22/21Z.
Winds will generally be 5 to 10 kts with gusts up to 20 kts, SW
then veering NW, and the NE behind the front.
EXTENDED AVIATION OUTLOOK...There may be restrictions mainly in
the early morning hours during the outlook period associated
with a moist onshore flow.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
GA...None.
SC...None.
&&
$$
Area Forecast Discussion
National Weather Service Cheyenne WY
831 PM MDT Tue Mar 21 2017
.UPDATE...
Issued at 831 PM MDT Tue Mar 21 2017
The forecast overall is in good shape for the rest of tonight.
Just added in some fog for the southern Laramie Range, eastern
foothills, and Cheyenne proper tonight within moist south-
southeast flow up the Cheyenne Ridge and Laramie Range. This
includes I-80 from Cheyenne to the Summit, and I-25 from the CO
border to Chugwater. HRRR guidance has been consistent showing fog
in this area for tonight, and agree with this assessment as
south-southeasterly winds favor stratus and fog development here.
Expect visibility to be reduced to a mile or less in the fog.
&&
.SHORT TERM...(This evening through Thursday night)
Issued at 250 PM MDT Tue Mar 21 2017
Forecast challenges deal with a potential winter storm Thursday
night into Friday.
Currently...Stationary frontal boundary lays over southeast
Wyoming this afternoon. Radar showing fairly widespread shower
activity along the front that is moving northeast at 30 MPH.
Strong low pressure seen on water vapor imagery still off the
Oregon coast.
For tonight, upper shortwave tracking northeast lifts stationary
front to the northeast to our northern counties. Short range HRRR
guidance showing showers lifting to the northeast with drier
conditions across the south.
A pretty warm day Wednesday as westerly winds predominate the
area. 700mb temperatures climb to +6C with some downsloping off
the Laramie Range. Looking at highs upper 60s/low 70s for areas
east of the Laramie Range with low 60s west.
Thursday is going to be unsettled as the Pacific low moves into
western Colorado. Widespread upper level diffluence over south
central Wyoming with precip beginning Thursday afternoon across
Carbon and Albany Counties. 700mb temperatures still above
freezing initially Thursday afternoon, but as the low tracks into
eastern Colorado, temperatures fall quite quickly. By 06Z Friday,
700mb temperatures down to -5C across Carbon County. Anticipate
rain changing over to snow quite quickly Thursday night. Strong
northeasterly winds at 700mb. ECMWF showing 55-60kts over the
Laramie Range. GFS 700mb winds 35-40kts. So looks like we should
be getting some strong winds with the snow as well.
.LONG TERM...(Friday through Tuesday)
Issued at 250 PM MDT Tue Mar 21 2017
Generally mild and rather unsettled weather anticipated across the
CWA this period in a progressive flow pattern. Pcpn will end
slowly across the southeast part of the CWA Friday as a vertically
stacked low drifts slowly east across the Kansas/Oklahoma area.
Windy conditions Friday over the plains but easing by late in the
day. Dry weather Friday night into Saturday as a short ridge
moves by then the next shortwave will move across later Saturday
into Sunday bringing another round of rain and higher-elevation snow
showers. Brief lull again late Sunday into Monday then the next in
the series of shortwaves arrives for late Monday into Tuesday
returning rain and snow to the fcst then.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 622 PM MDT Tue Mar 21 2017
Showers will continue across the area through the early overnight
period, but minimal impacts are expected from this activity. For
much of the area, winds will be out of the east to southeast
gusting 20-25kts or so this evening, switching to a more southerly
component with gusts increasing to 30kts tonight. The exception
will be in southern Carbon County where winds will remain out of
the southwest. Moderate winds and moist upslope flow look to
produce low stratus and areas of fog at KCYS tonight according to
the latest guidance. Added IFR cigs/vsbys after 07Z tonight, but
there is a chance conditions could drop below IFR at times through
early Wednesday morning. KSNY could have a similar stratus/fog
problem, but right now confidence is highest for only MVFR cigs.
Will reassess for the 06Z TAF issuance. VFR is expected
elsewhere, but will watch conditions closely this evening for
possible expansion of MVFR/IFR across the plains. Once cigs lift
Wednesday morning, conditions should remain mostly dry and breezy
through the day.
&&
.FIRE WEATHER...
Issued at 250 PM MDT Tue Mar 21 2017
A stalled front over southeast Wyoming interacting with upper level
disturbances will produce scattered showers and isolated
thunderstorms this afternoon along and west of Interstate 25. The
front will shift east into the plains Wednesday as west to
southwest winds increase ahead of a stronger Pacific low pressure
system. This low will track east across the central Rockies and
plains Thursday through Friday bringing widespread rain and snow
to the districts. Minimum relative humidities the next few days
will range from 20 to 30 percent, with fair to good nighttime
recoveries.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...None.
NE...None.
&&
$$
UPDATE...RJM
SHORT TERM...GCC/DEL
LONG TERM...RE
AVIATION...RJM
FIRE WEATHER...GCC
Area Forecast Discussion
National Weather Service Quad Cities IA IL
948 PM CDT Tue Mar 21 2017
.UPDATE...
Issued at 930 PM CDT Tue Mar 21 2017
Have updated to increase sky cover overnight and adjust mins up a
bit especially east central IA into northwest IL.
Lake Mi stratus propagating SSW at near 20 kts in wake of
pronounced wind shift. NAM and RAP mslp and surface wind fields
bring this lake enhanced boundary into far eastern cwa prior to
05z then toward Mississippi river overnight before washing out in
developing broad northeasterly low level flow. Attendant to this
boundary and evolving broad northeast flow at 20-25 kts in 1-3kft
agl layer will be lake enhanced stratus. NAM/RAP low level rh
progs have a decent handle on the lake stratus and followed for
sky grids going with pt-mocldy developing overnight across NW IL
into portions of eastern IA especially through the Hwy 30 to I-80
corridors... possibly reaching near IOW/CID toward daybreak. As a
result of this increase in cloud cover I have also nudged up lows
a bit. SW cwa will continue to see sct-bkn high cloudiness at
times overnight. Overall, expect skies to become partly to mostly
cloudy across much of the cwa. Updated grids/PFM/ZFP have been sent.
&&
.SYNOPSIS...
Issued at 307 PM CDT Tue Mar 21 2017
As expected the mid-level frontogenetic band of rain, triggered
by a short wave moving quickly across Iowa, has continued to
diminish and was pushing rather quickly to the southeast. The HRRR
model indicated the rain should exit the dvn cwa by late this
afternoon (4 pm).
&&
.SHORT TERM...(This Evening through Wednesday)
ISSUED AT 307 PM CDT Tue Mar 21 2017
Forecast focus on dry but chilly weather in the short term.
Tonight: Subsidence in the wake of the short wave pushing off to
our east should bring clear to partly cloudy skies for most of the
night. Canadian high pressure (1040 mb)centered in Manitoba will
slide to Lake Superior by sunrise. This will funnel cold air into
the area on north to northeast winds. Minimum temperatures will
be in the 20s.
Wednesday: As the high pressure pushes towards the eastern Great
Lakes region, winds will veer to the east to southeast. Mid/high
level clouds should increase as gradually strengthening mid-level
warm air advection develops on the return flow. The thickening
cloud deck should keep temperatures on the chilly side for late
March, with highs in the lower to mid 40s. This would be about
10 degrees cooler than normal.
.LONG TERM...(Wednesday Night through Tuesday)
ISSUED AT 307 PM CDT Tue Mar 21 2017
The weather pattern will be turning very active the second half of
the week across the Midwest and is expected to continue through the
end of the month. Some of the extratropical cyclones that develop
across the CONUS will have the potential to be strong. Water vapor
imagery shows numerous storms across the Pacific Ocean all the way
into eastern Asia.
That being said, the active pattern does not mean there will be a
continuous rain. There will be periods of dry weather. However,
precipitation does have the potential to average above normal
through the end of the month.
Quiet and dry conditions will be seen across the area Wednesday
night as high pressure moves into the eastern Great Lakes. Attention
then turns to the first rain event for Thursday.
The strength of the high and depth of the dry air will dictate when
precipitation develops and what it will initially be on Thursday.
The current model consensus has slight chance to chance pops west of
a Galena to Kewanee, IL line Thursday morning. However, this will
likely be the areal coverage by the noon hour on Thursday. The
entire area may start out dry at sunrise Thursday.
Profiles of the atmosphere do show a layer of dry air at the
surface. This dry air may be just enough to allow an initial period
of sleet before quickly changing to a rain/snow mix and then all
rain as the dry layer saturates.
Thursday afternoon there should be an area of rain moving from south
to north across the area as the stronger forcing acts upon an
elevated front moving through the area.
Thursday night the better forcing and elevated front move north of
the area. The increasingly moist and unstable air should allow the
precipitation to be showers with some elevated thunderstorms north
of I-80.
Mainly dry conditions should be seen across the area Friday morning
while the next storm system moves out of the Plains. By Friday
afternoon scattered showers along with some thunderstorms are
expected to develop with the better coverage west of the
Mississippi. Temperatures look to be well above normal.
Friday night on...
While the weather pattern is projected to remain very active, the
models continue to vary considerably from run to run on the overall
track and details regarding each storm system.
Dprog/DT of the model runs is suggesting a southward shift in the
storm track Friday night into Saturday.
Friday night and Saturday the model consensus has likely to
categorical pops. While the models disagree on the overall track and
details, it is starting to look like a widespread general rain event
with some embedded thunderstorms. Temperatures should generally
average above normal.
Saturday night into Sunday the model consensus has chance to likely
pops with the next system moving through the Midwest. The model
solutions are diverging on their respective solutions regarding how
quickly the system will exit the area or where it will track. Right
now the precipitation type looks to be all rain. There may or may
not be some embedded thunderstorms.
Sunday night the model consensus has slight chance to chance pops
mainly west of an Independence, IA to Macomb, IL line for the next
storm system. Depending upon on how quickly this system arrives, the
possibility does exist that Sunday night could be dry.
The model consensus has chance to likely pops on Monday and chance
pops Monday night for the next in the sequence of storm systems
moving through the Midwest. Right now the precipitation type looks
to be rain.
On Tuesday, the model consensus has mainly dry conditions for the area.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday Evening)
ISSUED AT 938 PM CDT Tue Mar 21 2017
Lake enhanced stratus is moving SSW at near 20 kts being handled well
by low level NAM/RAP rh progs, and supports MVFR cigs developing into
MLI overnight and possibly expanding to the other terminals as well.
Will update forecasts as trends play out in the next few hours. Northerly
winds around 10 kts will turn easterly overnight and may gust for a brief
period of time.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
UPDATE...McClure
SYNOPSIS...Haase
SHORT TERM...Haase
LONG TERM...08
AVIATION...McClure
AREA FORECAST DISCUSSION
National Weather Service Eureka CA
353 PM PDT Tue Mar 21 2017
.SYNOPSIS...An upper trough will generate occasional showers
tonight through Wednesday. Another storm will impact Northwest
California with heavy rain and strong winds Thursday night and
Friday.
&&
.DISCUSSION...Convection has been firing up over the coastal
waters today in advance of an approaching short-wave trough. A
few storms were strong enough to warrant special marine warnings
for winds up to 40 kt and possible waterspouts. We have not seen
more small scale vortices near shore and over land areas, but the
latest HRRR indicates the potential for storms with weak rotating
updrafts into early this evening, mainly across SW Humboldt and
Del Norte counties. The threat for low topped rotational storms
should diminish by late this evening. The leading edge of the
cold air boundary probably will not arrive til late tonight. With
steep mid level lapse rates and CAPE values below 500J/KG, low
topped storms will still be possible into the early morning hours,
primarily over the coastal waters.
Showers will most likely continue through Wednesday as weak
instability persists and NW onshore flow develops after trough
passage. The precip will wind down by Wed evening as a shortwave
ridge builds over the region. With a colder air mass settling over
the region Wed night, frost will be a distinct possibility across
interior Mendocino county as skies partially clear out. The
latest GFS and NAM12 indicate high boundary layer humidities with
virtually no offshore wind flow. It will probably be too foggy
with low overcast for frost to be serious concern. This will need
to be watched closely.
Primary focus Thursday and Friday will shift to an occluding
cyclone over the northeastern Pacific. A frontal boundary
extending southward from the cyclone is forecast to reach the
coast of NW California Thursday night, and then exit east of the
area Friday afternoon. High precipitable water values 1 to 3
standard deviations above climatology are forecast along the
front. This above normal moisture combined with strong ascent will
support locally heavy rain with the frontal passage. In addition,
advisory level wind gusts are likely as a 40-60 kt low level jet
develops along/ahead of the front. There is very little doubt that
the upper elevations of Humboldt and Del Norte counties will see
gusts around 50 to 60 mph with this storms if the models are
correct. For coastal areas near mean sea level, it is too early
to tell for sure how strong winds will get. Later runs from the
high resolution mesoscale models may provide better guidance.
After the Friday system moves east away from the area, the upper
flow regime is forecast to transition to northwesterly. This will
lead to periods of shortwave ridging followed by showery upper
troughs emanating from the Aleutians region during the Saturday
through Tuesday time period. The system slated to arrive Sunday
into Sunday night may be slightly colder (lower snow levels) but
with less moisture (not as much rain). Shortwave ridging early
next week should result in another semi-dry period Mon/Tue with
lesser rain chances.
&&
.AVIATION...THIS EVENING, MENTION VICINITY THUNDERSTORM FOR ALL
TERMINALS AS THERE WILL BE THREAT OF THUNDERSTORMS IN THE AREA. AS
WE LOSE THE DAYTIME HEATING AND THE ASSOCIATED INSTABILITY, THE
THREAT OF THUNDERSTORMS WILL DIMINISH LATER THIS EVENING. SHOWERS
WILL STILL BE IN THE AREA THROUGH THE LATE EVENING HOURS. BY LATE
NIGHT AND EARLY TOMORROW MORNING, SHOWERS WILL DIMINISH AND WE WILL
HAVE VICINITY SHOWERS THROUGH WEDNESDAY DAYTIME. DO EXPECT VFR
CONDITIONS TO PREVAIL THROUGH THE NEXT 24 HOURS. GUSTY SOUTH WINDS
THIS EVENING WILL DIMINISH OVERNIGHT. WINDS WILL BE LIGHT AND FROM
THE SOUTHWEST TOMORROW. /RCL
&&
.MARINE...ACTIVE WEATHER PATTERN WILL CONTINUE THROUGH THIS
WEEKEND, WITH FLUCTUATING WIND REGIMES AND SEA STAGES.
THE FORECAST PERIOD WILL START WITH GUSTY SOUTH WINDS OF 30
TO 35 KT TO THE COASTAL WATERS, WITH COMBINED SEAS AROUND 10 TO
11 FT THIS EVENING. THE WINDS WILL BE SUBSIDING THIS EVENING,
ALONG WITH SHOWERS AND ISOLATED THUNDERSTORMS. THE SEAS WILL BE
GRADUALLY SUBSIDING TO LESS THAN 8 FEET WEDNESDAY NIGHT. HAVE A
GALE WARNING FOR THE NORTHERN OUTER WATER THROUGH THIS EVENING,
AND HAVE SMALL CRAFT ADVISORIES FOR THE REST OF THE COASTAL WATERS
THROUGH WEDNESDAY NIGHT.
WINDS ON WEDNESDAY WILL SWAP TO THE NORTH AS A WEAK TRANSITORY HIGH
MOVES THROUGH THE AREA. ON THURSDAY MORNING, WINDS WILL SHIFT TO THE
SOUTH AND INCREASE AS A POWERFUL LOW AND ITS ASSOCIATED FRONT MAKES
LANDFALL ALONG THE WEST COAST. CONFIDENCE IS INCREASING THAT WE WILL
BE SEEING SOME SUSTAINED GALE FORCE WINDS. DO EXPECT COMBINED SEAS
TO INCREASE TO 10 TO 14 FEET LATE THURSDAY.
WINDS WILL BE DIMINISHING ON FRIDAY BEHIND THE WEATHER FRONT. SEAS
WILL REMAIN FAIRLY ELEVATED WITH A PERSISTENT BACKGROUND WESTERLY
SWELL AND PERIODS OF WIND DRIVEN WAVES. THE WAVE FORECAST IS FAIRLY
COMPLEX FOR THE NEXT WEEK. WAVE MODELS ARE SHOWING POTENTIALLY UP TO
7 DIFFERENT WAVE GROUPS TO IMPACT THE NW CALIFORNIA WATERS. /RCL
&&
.EKA WATCHES/WARNINGS/ADVISORIES...
CA...None.
NORTHWEST CALIFORNIA COASTAL WATERS...
Small Craft Advisory until 3 AM PDT Wednesday for PZZ450-455-475.
Small Craft Advisory until 3 PM PDT this afternoon for PZZ470.
Gale Warning until 9 PM PDT this evening for PZZ470.
&&
$$
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Area Forecast Discussion
National Weather Service Hastings NE
615 PM CDT Tue Mar 21 2017
.SHORT TERM...(This evening through Wednesday)
Issued at 238 PM CDT Tue Mar 21 2017
Biggest issue will be precip chances tonight.
Backdoor cold front helping to keep stratus locked in for much of
the day in our north/northeast and kept us cooler up there. The
HRRR seems to be doing a decent job with the cooler temperatures
up there for this afternoon and early evening.
As for the upcoming low-amplitude perturbation tonight, numerical
models have really backed off on this. Still have low POPs in our
west/north, with somewhat higher POPs in our far north, but the
main influence of this wave will focus primarily north of the CWA
once again. BUFKIT soundings continue to indicate the possibility
for sleet in our far north, so I stuck that in there late tonight
as a possibility.
For Wednesday, Upper level ridging will help ensure a dry day,
with seasonable highs in the lower 50s.
.LONG TERM...(Wednesday night through Tuesday)
Issued at 238 PM CDT Tue Mar 21 2017
Biggest issue will be determining chances and timing of potential
precipitation.
A succession of waves over the extended will keep chances of
precipitation for much of the forecast.
At the surface a lee low develops over Colorado as an inverted
trough/warm front extends northeast for Thursday. There is a
small worry of some hailers in our south during the early morning
as MUCAPEs of 500 to 1000 J/kg are not out of the question. Not a
lot of effective shear to work with, so not looking for widespread
severe weather by any means.
We probably will not see a whole lot from this during the day
Thursday as we will be on the stable side, but could stand a
better chance during the night. It will all depend on where the
instability corridor sets up, but it looks like it might wind up
being west of the CWA.
Thursday could be a stratus filled day if the NAM is right, and we
might wind up way cooler than the forecast 60s/70s.
Friday trends are for the surface low to be farther south, which
will essentially negate our shot at severe weather, and instead,
we could see a rain band set up north of the low somewhere on or
near us.
Saturday may turn out to be more damp as the upper wave becomes
more negatively tilted as it departs.
Another wave pulling into the Plains will help spawn surface
cyclogenesis is likely over the southern Plains by Monday. A
blended solution of ensembles and operational models was used in
this solution as there is not a lot of agreement with
placement/timing.
&&
.AVIATION...(For the 00Z KGRI/KEAR TAFS through 00Z Wednesday evening)
Issued at 611 PM CDT Tue Mar 21 2017
The MVFR ceilings should diminish as the sun goes down this
evening, but there are still some mid level clouds moving through
the area this evening and into the day tomorrow.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...None.
KS...None.
&&
$$
SHORT TERM...Heinlein
LONG TERM...Heinlein
AVIATION...JCB
Area Forecast Discussion
National Weather Service Gray ME
1038 PM EDT Tue Mar 21 2017
.SYNOPSIS...
An arctic front will push south through the region late tonight,
and produce a very cold and windy Wednesday. High pressure will
build in from the west Wednesday night through Thursday. High
pressure will shift east Thursday night. A warm front will
approach from the southwest Friday followed by a cold front
Friday night. High pressure will build south from Canada
Saturday through Sunday.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
1040 PM Update...Just a few minor adjustments to the forecast
based on latest trends in surface obs as well as satellite and
radar data.
745 PM Update...Little change to the going forecast. Occasional
snow continues in the higher terrain of the western ME Mountains
and the Whites. Scattered rain/snow grain showers are also
occurring from time to time further south. An arctic cold front
continues to approach from the NW is expected to sweep across
the region later tonight. A few squalls remain possible with the
front.
6 PM Update...Have updated the forecast mainly in the PoP/Wx and
temperature departments. Loosely organized snow banding is
taking place across the western ME mountains, some of which is
heavy based on some web cams. The HRRR continues a pretty narrow
band of potentially mod-hvy snow through the evening,
particularly across higher elevations of Franklin County. Have
increased snow amounts to a few inches there. Otherwise, an
arctic front is expected to move through later tonight - perhaps
allowing for a band of snow squalls (mainly in the mountains).
Previously...
Some mid lvl WAA associated with weak low pressure form ahead
of sfc cold front setting off a cluster of showers of rain and
snow moving across nrn zones at this times. This should shift E
in the next couple of hours, with a bit of a dry period. in the
hours around sunset. The sharp edge to the arctic air will move
through from late evening thru the pre-dawn. Scattered snow
showers are a good bet in the mountains, with some squalls
possible across the nrn zones. Models are stingy with bringing
much in the way of snow showers with the front into srn half of
NH or coastal plain of ME, but could see a few isolated SHSN
after midnight in these areas. Temps will drop slowly through
the evening, but once the cold front moves through the will
begin to fall off quickly late with lows 15-20 in the N and
around 30 in the south. Winds will also pick up fairly quickly
behind the front, but strongest winds will be during the day
Wednesday.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT/...
Strong CAA and gusty NW winds behind the front will allow for
temps for temps drop through out the day, with highs early the
day. Winds will pick up during the morning probably to around 20
mph with gusts around 40 mph at times, especially in the
afternoon. Models keep gusts below wind adv criteria, but it
gets close, so will have to watch for potential advisory in some
spots.
Temps will fall thru the teens and 20s during the afternoon,
with wind chills in the single digits below zero in the
mountains, and in the single digits above zero in the south, so
it will be quite cold. The March sun will only go so far to
counteract the strong CAA. Upslope snow showers will continue
through the morning with some accums in the favored upslope
areas and on the higher terrain.
Winds will be slow diminish Wed evening and temps will continue
fall through the night, with wind chills dropping blow zero
everywhere and in the -10 to -20 range in the mountains. Lows
will bottom out from around zero in the north to around 10 above
on the coast and in srn NH.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
Broad upper ridge will gradually replace a departing trough Thursday.
Surface high pressure building in from the west will produce a
mostly sunny day...although temperatures will remain well below
normal. Highs will range through the 20s north and lower to mid 30s
south.
High pressure will shift offshore Thursday night and return flow will
begin to bring warmer air back into the region. Expect high clouds to
spill over the ridge as a broad area of over-running set up to the
west. May see a few flurries or snow showers by daybreak but expect
any precip to be light and spotty generally falling off a mid
level deck. Lows will range from 5 to 15 north and will range
through the teens south.
Weak over-running precipitation will continue through the day Friday
ahead of a cold front approaching from the west. Will likely see
light snow mixing with or changing to rain in southern New Hampshire
and southwest Maine as boundary layer temps warm through early
afternoon. Models showing some differences in areal extent of
this warming with the ECMWF remaining significantly colder. In
any case QPF by the end of the day only amounts to a tenth of an
inch or less so any impacts will be minimal. Temperatures will
be fairly uniform across the region...ranging from the mid 30s
north to the mid 40s south.
Cold front will swing in from the west Friday night and will push
south of the area by Saturday morning. Looking for lingering rain
or snow showers to gradually end around midnight as the boundary
moves through. looking for partial clearing after midnight as high
pressure builds in from the north. Should see temperatures closer to
normal overnight with lows from the mid 20s north to the mid 30s
south.
High pressure building south from Canada will produce a mostly skies
Saturday. Not a lot in the way of cold air behind the front as it
stalls just southwest of the area so highs top out above normal
ranging from the mid 30s to lower 40s north and mid 40s to near 50
south.
Models diverge at this point with the ECMWF lifting the front
northward ahead of an approaching shortwave while the GFS parks it
to the southwest of the area. Have pretty much gone with SB numbers
for the remainder of the forecast and confidence quite low for days 6
through 8.
&&
.AVIATION /03Z WEDNESDAY THROUGH SUNDAY/...
Short Term...Could see some periods of MVFR overnight in SHSN at
KLEB, and especially KHIE, bit otherwise look for MVFR to
persist through Wed night. Strong NW wind gusts, to around 35kt
at times are expected on Wed, especially in the afternoon.
Long Term...VFR Thursday through Thursday night. MVFR/IFR
ceilings/vsby Friday and Friday night. VFR Saturday through
Sunday.
&&
.MARINE...
Short Term...Gales are now effect for all zones Wed into Wed
night, as strong NW flow moves in behind a cold front. With
very cold air spilling in, have issue fz spray adv for Wed
night. Wind should start to diminish a bit late Wed night.
Long Term...SCA`s likely Friday.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...None.
NH...None.
MARINE...Freezing Spray Advisory from 7 PM Wednesday to 10 AM EDT
Thursday for ANZ150>154.
Gale Warning from 8 AM Wednesday to midnight EDT Wednesday
night for ANZ153.
Gale Warning from 8 AM Wednesday to 8 AM EDT Thursday for
ANZ150>152-154.
&&
$$
NEAR TERM...Ekster
Area Forecast Discussion
National Weather Service Memphis TN
1012 PM CDT Tue Mar 21 2017
.UPDATE...
A cold front has pushed through the Mid-South this evening. As a
result, temperatures have dropped into the 50s and 60s behind the
front. Even though the front has passed, chances for showers and
thunderstorms will continue into the overnight hours as a
shortwave moves through the region. Current KNQA radar shows a
band of showers with a few embedded thunderstorms moving into
Northeast Arkansas, the Missouri Bootheel, and Northwest
Tennessee at this time. The latest HRRR brings this band south to
the Mississippi/Tennessee border by 6-7 AM CDT. Will update to go
likely POPS for areas north of a Memphis to Jackson line.
Otherwise, rest of forecast looks good. Update will be out
shortly.
KRM
&&
.DISCUSSION... /issued 338 PM CDT Tue Mar 21 2017/
Conditions supportive of severe weather near the Tennessee River
are quickly diminishing. Only showers and an isolated thunderstorm
or two are expected across the remainder of the Midsouth
overnight. We will likely cancel the watch within the hour.
Tomorrow we will be situated on the far eastern edge of a broad
ridge centered over the plains and on the Southern edge of high
pressure centered over the Great Lakes. Isolated showers can`t be
ruled out...but most areas will remain cloudy and dry. No
significant rain chances will return to the Midsouth until late
Friday as the ridge over the Plains strengthens and shifts slowly
East.
Temperatures tomorrow will be significantly cooler with abundant
cloud cover. Highs will be mostly in the 50s although the warmest
portions of North Mississippi may approach the middle 60s.
Temperatures will rebound quickly back into the middle 60s to
middle 70s Thursday.
Southerly flow will return Friday boosting temperatures back into
the middle 70s across most of the region. The ridge axis that will
keep us dry for the next few days will shift across the
Mississippi River early Friday resulting in Southwest flow over
the Midsouth.
Over the weekend into next week, we will be under progressive
flow. Two dynamic systems are expected to impact the Midsouth,
first Late Friday into Saturday morning and again Sunday night
into early Monday. Each of these systems could produce strong to
severe thunderstorms although exact details would just be a
guess. Both systems do appear they will have much more dynamic
energy to work with than todays storm...and temperatures should be
back in the 70s suggesting that thermodynamic support should be
adequate. A shortwave ridge oriented from Northwest to Southeast
will shift across the Midsouth Sunday between storm systems.
30
&&
.AVIATION...
A cold front located is moving through North MS. VFR conds prevail
with ocnl MVFR cigs behind the front tonight. Later tonight sct
shras will move across the Mid-South continuing into early Thu.
Mainly VFR conds expected Thursday. NE winds at 10-12 kts through
the period.
SJM
&&
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...None.
MO...None.
MS...None.
TN...None.
&&
$$
Area Forecast Discussion
National Weather Service Newport/Morehead City NC
950 PM EDT Tue Mar 21 2017
.SYNOPSIS...
Low pressure will move through the area tonight. The low
will move well offshore Wednesday as high pressure builds in
from the northwest. The high will continue to build over the
area through Thursday then slide offshore Friday. An area of
low pressure will approach the area late this weekend.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
As of 945 PM Tue...
Active MCS continues to roll across southern NC and most of SC
at this hour. This system has produced large hail in the
Charlotte area and especially in upstate SC. Latest GOES-R
satellite imagery showing the coldest cloud tops are over SC
with only a couple of strong storm cells over southern NC. Think
most of the strong storms will remain south of our CWA...but do
expect the possibility of a heavy downpour and a few rumbles of
thunder toward morning along with a few wind gusts. Further
north across the coastal plains...latest HRRR shows widespread
showers and have high chance PoPs far northwest to likely over
most of the remainder of the CWA overnight. Highs reached 80
degrees or better at several locations in the southwestern CWA
this afternoon. The cold front is moving very slowly and
continues on roughly on a HSE-PGV line and temperatures have
already dropped into the 50s at MQI and HSE.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH 6 PM WEDNESDAY/...
As of 330 PM Tue...
Clouds and even a few showers will linger into mid morning
Wednesday especially over the coastal counties. Drier air will
win out by midday, with a clearing sky by afternoon. Temps will
be much cooler, with a northeast flow dragging in cooler
weather. Highs by afternoon will still be near 60, but this will
be a good 20 degrees cooler than today, especially inland. The
pressure gradient between high pressure over the upper midwest
and the low off shore will also lead to breezy weather, with
gusts over 20 mph likely from mid morning on.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/...
As of 245 PM Tue...Arctic high pressure will build into the
region Wednesday night and Thursday bringing below normal
temperatures with much of the area dropping below freezing
Thursday and Friday mornings. The high will move offshore Friday
bringing moderating temperatures into the weekend. A frontal
system will approach from the west late in the weekend bringing
an increased chance of showers.
Wednesday night through Thursday night...Arctic high pressure
builds into the region Wed night through Thu night bringing
temperatures several degrees below normal and the threat of
below freezing temperatures across much of the area each
morning. Skies will be mainly clear through the period but could
see increased mid/high clouds late Wed night and early Thu as a
fast moving and weak shortwave moves through NW flow aloft.
Lows Thu morning expected in the upper 20s/lower 30s inland to
low to mid 30s along the coast. Highs Thursday will be in the
low to mid 50s well inland and southern areas but remain in the
mid to upper 40s NE sections and the OBX. Brisk northerly winds
will continue Thursday and wind chills will keep it feeling
more like the mid 30s to mid 40s across much of the area. Cold
again Thu night/Fri morning with temperatures near freezing
inland and 35 to 40 along the coast.
Friday through Tuesday...The high moves offshore Fri bringing
moderating temperatures through the weekend and early next week.
Models trending drier for Sat and think Fri, Sat, and likely Sat
night will remain dry...though could see increasing shower
chances off the coast near the Gulf Stream Sat. Models show a
vertically stacked low pressure system tracking across the Ohio
River Valley Sun, then gradually weakening as it moves off the
Mid-Atlantic coast Mon with a trailing cold front sliding across
the area. There continues to be a good bit of uncertainty in
how this system evolves and impacts ENC with differences between
the GFS and ECMWF. Continued to favor the previous forecast and
WPC, which leans more towards the ECMWF. Continue chance PoPs
Sun and Mon, then tapering to slight chance Mon night and Tue.
Will keep sc thunder mention with marginal instability and
shear. Temps forecast to warm into the 60s inland Fri, then
into the low/mid 70s over the weekend, though coastal areas,
especially the OBX will be several degrees cooler in the 60s.
&&
.AVIATION /02Z WEDNESDAY THROUGH SUNDAY/...
Short Term /Through 00Z Thursday/...
As of 715 PM Tuesday...Not only of changes in the overall trends
for this TAF cycle. Line of showers and a few embedded
thunderstorms along the outer edges of a strong MCS which will
cross most of South Carolina should arrive at the TAF sites
between 04z and 08z. This line of showers will cross the CWA and
move offshore early Wednesday morning. Currently forecasting
some MVFR ceilings to coincide with the highest precipitation
threat from 07z to about 12z.
A return to VFR is expected after 12Z Wednesday but a mid deck
will linger through late morning before total clearing from the
north. Light northeast winds tonight at less than 10 kts will
increase Wednesday, with northeast winds 10 to 20 kts common all
terminals.
Long Term /Wed night through Sunday/...
As of 245 PM Tue...Pred VFR conditions expected Wed night
through Sat...though cannot rule out patchy early morning fog
late in the week as temps/dewpoints moderate. Sub-VFR conditions
possible Sunday as a frontal system approaches the region with
scattered showers developing.
&&
.MARINE...
Short Term.../through Wednesday/...
As of 950 PM Tuesday...Frontal boundary moving slowly south
currently on a Hatteras to Greenville line. Winds are generally
light NE north of Cape Hatteras and SW to the south at speeds of
10 knots or less. Seas are in the 3-5 foot range currently.
No major changes to forecast. A Gale Warning is in effect for
Wednesday/Wednesday evening for all of the coastal waters
outside of the far northern waters, along with the Pamlico
Sound. A small craft advisory has been issued for the far
northern coastal waters from Oregon Inlet north, along with
Albemarle sound and Alligator River. Winds will be NE to NNE
through the period, 25 to 35 kts in the gale warning and 25 to
30 (with occasional gusts to 35 kts in the advisory area). In
fact over the far end of the Albemarle sound and the southeast
part of our northern waters, brief gales are possible but not
long enough in duration to include them in the warning. Waves
will run between 5 and 10 feet.
Long Term /Wednesday night through Sunday/...
As of 245 PM Tue...Gusty north winds 20-25 kt Wed evening will
slowly diminish late Wed night and Thu to around 10-20 kt by Thu
afternoon. Light winds expected Fri as the high shifts off the
coast, with S/SW winds re-developing and increasing to 10-15 kt
Fri night though Sunday. Seas 6-10 feet Wed evening, gradually
subsiding and should drop below 6 feet by late Thu afternoon and
early evening. Fri though Sun expect seas pred 2-4 feet.
&&
.MHX WATCHES/WARNINGS/ADVISORIES...
NC...None.
MARINE...Gale Warning from 9 AM to 8 PM EDT Wednesday for AMZ135.
Small Craft Advisory from 9 AM Wednesday to 2 AM EDT Thursday
for AMZ130-131.
Gale Warning from 7 AM to 9 PM EDT Wednesday for AMZ152-154-
156-158.
Small Craft Advisory from 7 AM Wednesday to noon EDT Thursday
for AMZ150.
&&
$$
SYNOPSIS...EH
NEAR TERM...CTC
SHORT TERM...EH
LONG TERM...RSB/CQD
AVIATION...CTC/EH/CQD
MARINE...CTC/EH/CQD
Area Forecast Discussion
National Weather Service Melbourne FL
940 PM EDT Tue Mar 21 2017
.DISCUSSION...
Only change to the forecast was to show an increase cloud cover late
tonight across the north as increasing westerly flow above the
boundary layer combined with some cyclonic flow may produce some
stratus and patchy fog spreading E/SE from north FL and the Gulf
coast. Otherwise, winds and temps look good for the overnight.
Overnight-Wednesday...(previous)
High pressure ridge over the southern CWA will slip southward and
weaken ahead of increasing westerly pre-frontal flow ahead of a weak
back door frontal boundary, which the models continue to accelerate
faster toward/into the northern CWA compared to previous runs. 12Z
guidance is now showing increasing NE winds leaking out ahead of the
boundary/main surge, reaching the NE CWA and adjacent central
coastal areas between 21Z-00Z, with any showers holding off over
water/land until after 00Z, though it`s likely they`ll be knocking
on the door of the CWA/MAOR not too long after.
MOS temps for tonight are cooler across the southern CWA (L-M50s)
compared to the north (U50s), which fits scenario of a retreating
surface ridge over the southern CWA, along with weak return (WSW-W)
boundary layer flow on its north side. Wednesday maxes will reach
L80s along the coast ahead of an afternoon ECSB, and M80s inland.
&&
.AVIATION...
Mainly VFR/SKC. MOS guidance, HRRR and local WRF are indicating some
stratus and patchy fog late tonight across the north. Have introduced
a TEMPO for IFR CIGs at LEE with MVFR VSBYs. This may need to be
expanded eastward to include MCO/SFB/DAB.
&&
.MARINE...
Tonight-Wed...(Modified) Slow decay in NE swell will continue
overnight into Wednesday, with a continued lack of significant wind
chop, given the developing offshore flow. Increasing northerly flow
will spread into the Volusia county waters late Wed behind a back
door front. Seas 3-5FT tonight will subside to 3-4FT around
sunrise, and 2-3FT late Wednesday afternoon.
&&
.FIRE WEATHER...(previous)
Wed...Marginally low min RH values in the L30s expected south of
Lake Kissimmee and Melbourne on Wednesday afternoon, inland away
from the coast. However, lack of sufficiently high ERC values and/or
sustained windspeeds precludes any potential RFW issuance.
Thu/Sun...Brisk onshore surface/transport flow thru Sat will
diminish on Sun as high pres builds over the W Atlc and gradually
erodes. The extended pd of onshore flow will all but ensure min RH
values remain well abv critical lvls thru the upcoming weekend.
&&
.PRELIMINARY POINT TEMPS/POPS...
DAB 58 81 64 74 / 0 10 40 40
MCO 59 85 63 78 / 0 0 20 40
MLB 58 82 65 75 / 0 0 40 60
VRB 55 82 65 76 / 0 0 40 60
LEE 60 84 61 78 / 0 0 20 40
SFB 59 84 63 77 / 0 0 30 40
ORL 60 85 62 78 / 0 0 20 40
FPR 54 82 64 76 / 0 0 40 60
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...None.
AM...None.
&&
$$
Kelly/Sedlock
Area Forecast Discussion
National Weather Service Pocatello ID
156 PM MDT Tue Mar 21 2017
.SHORT TERM...Tonight through Friday.
A surface low will push through Idaho tonight. It will spread rain
and very high elevation snow showers through all of southeast
Idaho this evening. Snow levels start at 9000 feet then drop to 6
to 7 thousand feet by morning. Have 1 to 3 inches above 8000 feet
in grids through Thursday morning. Most precipitation will shift
to southern and eastern highlands Wednesday night through
Thursday. An upper ridge should bring dry conditions Thursday
night and through Friday morning. Another system will likely
spread precipiation back into the central mountains Friday
afternoon. Will have much cooler temperatures on Wednesday and
Thursday with warming to again well above normal ahead of the
next system on Friday.
GK
.LONG TERM...Friday night through Tuesday. Progressive spring
pattern continues with multiple shortwave troughs passing through
East Idaho. Best chance at DRY weather occurs Sunday otherwise
precipitation expected nearly every period. Multiple cold fronts
gradually drop temperatures through the period toward climatic
normals, mainly Sunday and again Monday night. Still do not expect
snow levels to reach valley floors, but moderate accumulations
mainly above 6500 feet could be possible. DMH
&&
.HYDROLOGY...Snow melt runoff continuing to impact East Idaho. Water
still running in many places, and all advisories have been
continued. Portneuf River remains above flood stage with warning in
place. Latest forecast crests river just at moderate stage with
secondary crest just above moderate stage this weekend. Bear River
continues to climb but forecasts keep river just below flood stage
so have continued watch. Snake River at Blackfoot just above action
stage through the week without a significant climb. Opted to
continue broad river statement managing overall conditions across
the region. Only other change today was to remove portions of the
flood watch in the Snake Plain where snow cover has dissipated.
DMH
&&
.AVIATION...VFR and breezy conditions at many locations this
afternoon. So far weak showers trying to develop near KSUN and KDIJ
otherwise do not expect precipitation to develop until later this
evening. Models again struggling with timing and placement of
precipitation but consensus still points to 00Z-09Z being the focus
across the region. HRRR also developing what appears to be a
consolidated outflow associated with the main batch of convection.
This could bring the winds back into the 15-20kt sustained range
briefly as the convection passes through. DMH
&&
.PIH WATCHES/WARNINGS/ADVISORIES...
Flood Watch through Thursday morning for IDZ017>019-021>025-031-
032.
&&
$$
Area Forecast Discussion
National Weather Service Raleigh NC
935 PM EDT Tue Mar 21 2017
.SYNOPSIS...
A cold front will push slowly southward through the area tonight.
Cool high pressure will build into the region from the north
Wednesday through Thursday night, then shift off the East Coast on
Friday.
&&
.NEAR TERM /Through Tonight/...
As of 935 PM Tuesday...
Severe storms just to our SW, along the southward-pushing surface
frontal zone, are knocking on our CWA`s door, moving into more
favorable deep layer shear, but the thermodynamic environment is
much less favorable in our area for maintenance of these cells as
they ease into our area and leave behind the high mid level lapse
rates (7.5-8.0 C/km over the W Carolinas). We`ll continue to see
showers and storms cross our SW and extreme southern sections
through the overnight hours as the MCV tracks SE across SC and far
southern NC, supported by strong upper divergence in the right
entrance region of a small 120+ kt jet to our north. The initially
moderate CAPE over our SW sections and to the S and SW will steadily
dwindle and shift further southward over the next few hours
according to recent RAP runs, as the surface mass convergence zone
drops southward toward the NC/SC border. We may still see some
lighter showers spread up toward the Triangle and further NE over
the Coastal Plain beneath the upper divergence maximum, ahead of the
passing 850 mb trough. Will maintain likely pops overnight, with an
isolated strong storm or two possible just for the next couple of
hours, trending to low chance pops over the rest of the southern and
eastern CWA, and low to no pops in the far NW. Expect lows in the
upper 40s across the northern tier to the mid 50s SE. Skies should
remain cloud for much of the night, with partial clearing in the NW
late as drier air filters in with downslope low level flow. -GIH
Earlier discussion from 705 pm: Quick update to nudge low precip
chances a bit farther northward, in accordance with convection-
allowing model trends and depictions of low level moisture
convergence along and ahead of the incoming 850 mb trough. Still
expect likely showers and storms across the extreme southern CWA,
although will need to monitor trends, given that the low level theta-
e ridge is weakening, with decreasing 850 mb winds, which may yield
lower coverage or a suppression of better coverage to the south. -GIH
&&
.SHORT TERM /WEDNESDAY AND WEDNESDAY NIGHT/...
As of 115 PM Tuesday...
Expect a clearing trend in the morning as a drier airmass advects
into the region from the north, with clear skies during the
afternoon and evening. Cold advection is expected to persist for the
majority of the diurnal heating cycle on Wed as Canadian high
pressure builds into the Mid-Atlantic from the NW. Expect highs much
cooler than today, in the mid/upper 50s N/NE to lower 60s S/SW. Lows
Wed night may be tempered by increasing mid/upper level cloud cover
after midnight. Will indicate lows ranging from the upper 20s (rural
and low-lying areas east of I-95) to lower/mid 30s. -Vincent
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
As of 243 PM Tuesday...
With the cP airmass centered over the area Thursday and Thursday
night, temperatures through the period will average a good 10 to 15
degrees below normal. A potentially opaque canopy of high clouds
Thursday morning should diminish in the wake of the exiting NW flow
disturbance, allowing for afternoon sunshine. Highs 50 to 55.
High level moisture/cirrus blow-off advecting downstream from the
closed cyclone over the Central US could produce fair to partly
cloudy skies Thursday night, which could impede radiational cooling
a bit. Lows in the lower to mid 30s.
The modified Canadian parent high will shift east and offshore on
Friday, with southerly return flow allowing for a quick moderation
into the 60s on Friday and then into the 70s by Saturday. Meanwhile,
ridging aloft will keep it dry through the day on Saturday.
Strengthening warm moist air advection on the eastern periphery of
the closed mid/upper level cyclone moving east-northeast into the
Ohio Valley and Lower Great Lakes will result in increasing pops in
the form of showers and possibly a few thunderstorms Saturday night
and into the day on Sunday. The most recent 12z/21 GFS has trended
farther north than previous runs, and is significantly less wet than
previous runs. As such, will keep pops at chance, and highest in the
west. If this more northern track solution is realized, Saturday
night and Sunday could end up being mostly dry across central NC,
with mostly in the way of clouds across the area. Additionally, with
the low farther removed from the area, resultant weak forcing will
not bode well for any severe weather. Highs Sunday in the 70s.
On the heels of the dampening wave moving off the Mid-Atlantic coast
Sunday night, another shortwave trough, of lower amplitude, will
skirt quickly east across the Central US on Monday and will approach
the area late Monday night and into the day on Tuesday.
Between these two systems, expect to see a lull in precip chances on
Monday, with rain chances ramping back up again Monday night and
Tuesday.
Continued mild with highs in the 70s. Lows in the 50s.
&&
.AVIATION /01Z Wednesday through Sunday/...
As of 915 PM Tuesday...
A lead frontal zone now stretching from near EWN to JNX to JQF, and
associated focus for scattered showers and storms and sub-VFR
conditions mainly at FAY through 09, will settle Swd tonight.
Generally Nly winds, between 6-12 kts, will develop behind the front
overnight. A secondary cold front and leading edge of strong
continental polar high pressure will surge Swd through central NC
early Wed; and this will result in strong and gusty NEly winds in
strong surface pressure rises and cold air advection between 12-18Z
Wed, with lessening winds during the afternoon.
Outlook: There will be a chance of MVFR-IFR visibility restrictions
in radiation fog in SErn NC Fri morning, including at FAY and
perhaps RWI, then again forecast area-wide on Sat morning.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SYNOPSIS...Hartfield
NEAR TERM...Hartfield
SHORT TERM...Vincent
LONG TERM...CBL
AVIATION...MWS
Area Forecast Discussion
National Weather Service Springfield MO
717 PM CDT Tue Mar 21 2017
.SHORT TERM...(This evening through Wednesday)
Issued at 257 PM CDT Tue Mar 21 2017
Showers and a few thunderstorms developed across much of the
region this morning and into the afternoon hours. A few elevated
storms were able to reach severe limits. Much of what`s left
early this afternoon is showers and storms within area of
strongest isentropic upglide and ascent within an upper level
impulse sliding southeastward.
Through the afternoon and into the evening, short term models are
hinting at some additional development. RAP shows around 500-1000
J/KG of instability across much of the region, although it should
be noted the RAP`s CAPE values have been under-performing (to say
the least). Elevated instability, a boundary (as seen on visible)
dropping southward, and subtle isentropic support will help kick
off additional activity along or just south of the HWY 54
corridor. This activity should begin to shift southward through
the late afternoon and evening.
Although no widespread severe weather is anticipated, a
few marginally severe hail reports can`t be ruled. The best shower
and storm potential will end up settling further south along the
MO/Ark border through the overnight and into Wednesday morning.
With the surface front remaining just to our south through
Wednesday, we will keep at least some mention of rainfall with
overrunning, but at the moment there is no signal for anything
more than scattered coverage.
.LONG TERM...(Wednesday Night through Tuesday)
Issued at 257 PM CDT Tue Mar 21 2017
The front to our south, which should keep our region in the cool
sector through much of the short term should slowly move
northward as heights aloft begin to increase. Still, proximity of
the frontal boundary along with subtle H5 impulses should help
keep the rain chances nonzero through Thursday.
A potent upper level system will begin to slide eastward toward
the Missouri Ozarks and southeast Kansas by Friday. A deep surface
low will develop in the high plains region and slide generally
along and slightly north of the I44 corridor through late
Saturday.
Showers and Thunderstorms will develop along or just ahead of the
cold front. Although instability looks very marginal at this
time, wind dynamics and bulk shear will be supportive of at least
an isolated wind threat late Friday. Post frontal showers/storms
are then expected as the upper level low slowly moves through the
region by early Sunday. Some of these storms may have a hail risk.
Just as the weekend storm moves out, another mid level wave will
begin to slide across the plains late Sunday and into Monday.
Being in the warm sector, we`ll need to keep our eyes open for
more strong storms during this time. Similar to the earlier
system, instability looks marginal with slightly limited moisture.
The end of the period, we`ll finally get a small break as upper
level ridging takes place on Tuesday/Wednesday before our next
potent mid-level trough takes shape across the Rockies.
The good news is our current pattern will bring several
opportunities for much needed rainfall across the area.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 651 PM CDT Tue Mar 21 2017
After a front moved through the area earlier today, surface winds
were out of the northeast and gusty. VFR ceilings around 5kft
will continue into this evening as a mid level boundary moves
south through the region. This will bring the potential for some
additional showers or an isolated storm to the Ozarks during the
evening and overnight hours. Ceilings are expected to remain VFr
through the forecast period as the front from earlier today
wanders north and south across northern Arkansas.
&&
.SGF WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&
$$
SHORT TERM...Frye
LONG TERM...Frye
AVIATION...Hatch
Area Forecast Discussion
National Weather Service Shreveport LA
1042 PM CDT Tue Mar 21 2017
.DISCUSSION...
Have made a few changes to the ongoing forecast by adding
areas of fog to parts of East and Northeast Texas and lower
parts of Northwest and North Central Louisiana. Adjusted the
expected sky conditions and current trends in the dew points
and winds. Surface low pressure centered over East and Southeast
Oklahoma and West and Southwest Arkansas with a cold front
from the surface low near Fort Smith Southeast to near Pine
Bluff Arkansas and on into North Mississippi. This boundary will
continue to backdoor into the Four State Region during the
late night and early morning hours Wednesday with the
surface low retrograding into North Texas. Will continue the
current chances for showers and thunderstorms with the boundary
and in its wake over mainly the more Northern half of the
forecast area. By late in the day Wednesday the front will move
into Deep East Texas and across Central Louisiana where it looks
to become nearly stationary overnight Wednesday, and then work
back Northeast on Thursday as a warm front. /06/
&&
.PREV DISCUSSION... /issued 550 PM CDT Tue Mar 21 2017/
AVIATION...
Prevailing SKC attm across our terminal airspace but that will be
changing as we go through the overnight hours and through much of
Wednesday. A tight pressure gradient across the Southern Plains
will begin to relax this evening as a weak cold front currently
across Northern Ms, Northern Ar and Eastern Ok will begin
backdooring itself into our terminal airspace overnight. This
frontal boundary should be pushing through the TXK/ELD terminals
around 06-08z, near the SHV/MLU terminals in the 09/11z timeframe
before the boundary stalls. There are some questions as to whether
or not the boundary will continue moving south and west into the
TYR/GGG terminals as per the HRRR so will make this adjustment if
and when the 00z progs come in line with this scenario for the 06z
package.
Ahead of the backdoor cold front, should see MVFR/IFR ceilings
come north from SE TX overnight, encompassing the TYR/GGG and LFK
terminals with the possibility of LIFR ceilings and VSBYS at the
LFK terminal towards daybreak. Low clouds should filter in the
region in the wake of the backdooring cold front as well with
IFR/MVFR ceilings possible. MVFR ceilings may be stubborn to mix
out during the afternoon on Wed, especially in the wake of the
backdoor boundary and assuming the boundary stalls before pushing
into the TYR/GGG/LFK terminal airspace, low ceilings should mix
out quickly Wed morning/afternoon.
Post frontal winds with be 5 to 10kts from the NE to ENE on Wed.
13
&&
.PRELIMINARY POINT TEMPS/POPS...
SHV 60 77 59 84 / 10 10 10 10
MLU 58 75 57 84 / 10 10 10 10
DEQ 57 70 51 78 / 20 20 10 10
TXK 56 71 53 80 / 20 20 10 10
ELD 56 72 52 84 / 10 20 10 10
TYR 61 79 61 85 / 10 10 10 10
GGG 61 77 60 84 / 10 10 10 10
LFK 61 83 61 86 / 10 10 0 10
&&
.SHV WATCHES/WARNINGS/ADVISORIES...
AR...None.
LA...None.
OK...None.
TX...None.
&&
$$
06/13