Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 12/17/16
Area Forecast Discussion
National Weather Service Miami FL
804 PM EST Fri Dec 16 2016
.UPDATE...
The 17/0000Z MFL sounding indicated 10-15 KT of easterly flow
below 850 mb with westerly winds aloft. Tonight, sufficient low
level moisture, along with weak convergence, will allow for
shower development. The HRRR and Hi-Res WRF continue to show
isolated light showers over the Atlantic late this evening. This
activity is should push towards the east coast metro by late
tonight. However, not expecting much in the way of accumulation.
The rest of the forecast grids appear on track.
&&
.PREV DISCUSSION... /issued 630 PM EST Fri Dec 16 2016/
AVIATION...
The winds will remain easterly tonight into Saturday over all of
South Florida taf sites. The winds will be 5 to 10 knots tonight
before increasing to 10 to 15 knots on Saturday. The only
exception is at KAPF taf site where the winds will be around 5
knots tonight. The VIS and Ceiling will also remain in VFR
conditions tonight into Saturday at all of South Florida taf
sites along with dry weather.
AVIATION...54/BNB
PREV DISCUSSION... /issued 419 PM EST Fri Dec 16 2016/
DISCUSSION...Visible satellite imagery this afternoon showed
clear skies aloft with fair weather strato-cumulus scattered
below. Easterly winds this afternoon have been breezy, gusting on
average 10-15 mph across the area. These winds will continue into
tonight, especially along the east coast, as surface high pressure
slowly edges over the mid Atlantic waters. A minor increase in
low- level moisture and instability has warranted slight chance
PoPs over the Atlantic waters and eastern portions of the
peninsula tonight. Short term models, including the HRRR and Hi-
Res WRF indicate this activity developing late into the evening.
However, not expecting much in the way of accumulation.
This weekend, upper level ridging will allow for large scale
subsidence and warming over the region. Maximum temperatures will
reach the low 80s along the east coast metro and mid 80s towards the
western interior, 5 to 10 degrees above average. Low temperatures
may only fall to the mid 70s along the east coast metro and upper
60s further west, 10 to 15 degrees above average. Both the daily
high maximum and high minimum temperature records will be in
jeopardy of being tied or broken. Surface high pressure near the
western Atlantic will allow for persistent southeast winds and
increasing low level moisture. Light showers will be possible
mainly over the Atlantic and along the eastern portions of the
peninsula through Sunday afternoon.
Early to mid next week, both the GFS and ECMWF slowly break down the
ridge over Florida, as a cold front approaches the southeast CONUS.
Temperatures should fall back down to average for this time of
year with southeast/easterly flow. Enough low level moisture will
exist for a couple showers to develop, mainly along the eastern
and northern portion of the CWA. Models indicate the weakening
front may eventually pass over the region late Thursday into
Friday.
MARINE...Surface high center sliding off the east coast into the
Western Atlantic through the weekend will lead to a tightening
pressure gradient across the local waters. Expect persistent
southeasterly winds for Saturday and Sunday.
Wind speeds in the Atlantic waters will be around 15-20 kts, where
those operating small crafts should exercise caution, and 10-15
kts across the Gulf.
Pressure gradient diminishes into next week as another frontal
boundary sags into the FL peninsula. Southeasterly winds 10-15kts
for all the waters will prevail through mid week.
AVIATION...
VFR through the period with easterly winds picking up throughout
the day. Winds should become lighter overnight before picking up
again on Saturday during the day.
&&
.PRELIMINARY POINT TEMPS/POPS...
West Palm Beach 79 72 83 76 / 10 20 20 30
Fort Lauderdale 78 73 83 76 / 10 20 20 30
Miami 82 73 85 75 / 10 20 20 30
Naples 82 66 85 71 / 10 10 10 10
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...None.
AM...None.
GM...None.
&&
UPDATE...27/JT
DISCUSSION...27/JT
MARINE...27/JT
AVIATION...54/BNB
Area Forecast Discussion
National Weather Service Charleston WV
1014 PM EST Fri Dec 16 2016
.SYNOPSIS...
Storm system this weekend starts as wintry mix north late tonight
and early Saturday, then all rain and much warmer Saturday.
Turning colder again Sunday, with a change back to snow.
&&
.NEAR TERM /THROUGH SATURDAY/...
As of 1005 PM Friday...
Elected to extend the Perry/Morgan/Athens portion of the advisory
until 12Z. Otherwise no changes made attm.
As of 705 PM Friday...
Updated hourly temp grids to reflect latest trends using HRRR and
the official database. This resulted in only minor changes
overnight. The remainder of the forecast is by and large on track.
There is a concern that portions of SE OH...ie Perry/Morgan...may
see more ice accretion than previously forecast. The hi res models
along with RAP/NAM/GFS are putting out near half an inch of QPF in
a 3 to 4 hour window late tonight. This is in response to an
increasing LLJ which will bring about significant WAA aided by a
short lived increase in frontogenetic forcing and lift. Surface
temps in those locales likely will be just below freezing when
this occurs, giving concern for a bit more ice. This is
compounded by the cold ground which would likely support freezing
up to a 34 degree air temp if precip rates are low. The caveats
are the dry air near the surface which most of the models are not
currently handling well. Another caveat is high precip rate even
if the beefier qpf is realized, which would limit ice accretion.
Given that, the belief is that ice totals would fall just short of
ice storm warning criteria. This will be monitored over the next
several hours though. I did raise the ice totals to near 2 tenths
for those two counties.
As of 155 PM Friday...
An otherwise mainly rain event in warm advection overnight
tonight into Saturday, will be complicated by very dry arctic air
in place since early Thursday morning. This will not only slow
the rise in temperatures through tonight, but rain may continue to
freeze on ground surfaces for an hour or two after surface
temperatures climb above freezing.
Forecast temperatures are below guidance early on given they were
running as much as 5 F degrees below guidance early this afternoon.
Gradually brought temperatures closer to guidance through Sunday
morning as the warm air finally takes over.
Thus, rain overspreading the area mainly from the west tonight
will arrive while surface temperatures are still below freezing.
Have freezing rain up to 34 F degrees to account for the very
cold / frozen ground. This results ice accumulations similar to
the previous package from the middle Ohio through central and
northern WV, and in the northern and central WV mountains.
Expanded the advisory a tier of counties in the west where the
probability of precipitation early on is highest.
Temperatures continue climbing as rainfall coverage decreases in
the warm sector. Guidance close to previous except a little lower
in the middle Ohio Valley Saturday afternoon, as the rain persists
a little more there.
&&
.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY/...
As of 240 PM Friday...
Forecast guidance is in good agreement for a powerful cold front
to cross the region Sunday morning. Deep southwesterly return flow
with strong low level jet of 70KTs to 80KTs at H850 will transport
moisture into the region from the Gulf out ahead of the
approaching cold front. Given the ample forcing and elevated Cape
values of 200 J/Kg, it is possible we may see some embedded
thunderstorms early Sunday morning, but not enough confidence to
put that into the forecast at this time. Also, ensembles are
showing PWATs in the 1.25 inch range which is 3 to 4 standard
deviations above normal for this time of year. Good news is that
although this all points to heavy rain, the front has a strong
push so not expecting prolonged heavy precipitation. For now I`m
thinking widespread QPF amounts near 1 to 1.5 still, but some
localized amounts of 2 inches will certainly be possible with
these ingredients in place. This should not be enough to cause
much hydro issues, but could see some minor flooding in our usual
poor drainage areas.
Still quite a bit of uncertainty with p-type as the cold air slams
in behind the front. Chatting with WPC they said it perfectly that
the dense arctic air invading the OH valley early Sunday morning
could catch-up and undercut the solid precip zone for a burst of
snow and ice. For now I have kept snow totals fairly conservative
across the region with about 0.5 inch in the Lowlands and a max of
about 2 inches at Snowshoe where orographic accent should
certainly enhance QPF values behind the front.
Finally, the only other concern, with the strong low level jet out
ahead of the front, that we may see some strong gusts over the
higher ridges, but not enough confidence at this time to bump
wind speeds over advisory criteria.
High pressure starts to push in Sunday night and will make for a
cold but dry day on Monday.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
As of 245 PM Friday...
High pressure looks to be in control for the bulk of the work
week. Guidance continues to highlight a clipper system passing to
our north and will likely push a cold front through our region on
by Thursday. However, high pressure and a large ridge looks to
quickly replace the cold air for the weekend, but still a lot of
spread in the models and ensembles for this time period. For now I
decided to simply stick with a blend of forecast guidance from Day
4 onward.
&&
.AVIATION /03Z SATURDAY THROUGH WEDNESDAY/...
As of 1010 PM Friday...
Amended the TAFs to include LLWS at all sites given the strength
of the LLJ and the relative stable layer near the surface.
As of 715 PM Friday...
A warm front will bring mixed wintry precipitation starting late
tonight...primarily after 06Z. The mixture of mainly sleet and
freezing rain will quickly transition to just freezing rain, and
then rain in most locations by dawn Saturday. Freezing rain is
expected to last longest at KPKB...approximately 3 hours...with
remaining terminals only expecting a brief bout with freezing rain
such that confidence was too low to include in remaining TAFs
aside from KCKB. CIGS and VSBY will lower along the warm front
across SE OH overnight...eventually bottoming out into LIFR
conditions. This is expected to spill over into WV during the
morning hours...affecting remaining TAF sites with MVFR CIGS with
IFR CIGS at KCKB.
Southeast flow at the surface gradually increases tonight.
Southwesterly flow aloft will increase 50 to 70 kts by 12Z. Warm
air overriding the cold air may limit increasing wind speeds at
the surface, and low level wind shear is possible in the
mountains, Saturday morning. This ends when surface flow veers to
the southwest, increases and becomes gusty, as the low level cold
air is taken out.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 00Z SUNDAY...
FORECAST CONFIDENCE: Low to medium tonight.
ALTERNATE SCENARIOS: Timing / persistence of freezing rain may
vary. Timing and extent of MVFR or worse conditions toward dawn
and into the daylight morning hours Saturday may vary.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
DATE SAT 12/17/16
UTC 1HRLY 03 04 05 06 07 08 09 10 11 12 13 14
EST 1HRLY 22 23 00 01 02 03 04 05 06 07 08 09
CRW CONSISTENCY H H H H H H H H M M M L
HTS CONSISTENCY H H H H H H H M H L L L
BKW CONSISTENCY H H H H H H H H M M M L
EKN CONSISTENCY H H H H H H L H H H H L
PKB CONSISTENCY M M M M M M H H H H H M
CKB CONSISTENCY H H H H H H M M M M M L
AFTER 00Z SUNDAY...
IFR possible in rain Saturday night, changing to mixed
precipitation and then snow Sunday morning and midday, ending
west to east in the afternoon.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...Freezing Rain Advisory until 9 AM EST Saturday for WVZ520-
522>526.
Freezing Rain Advisory until 5 AM EST Saturday for WVZ007>011-
016>020-028>032-039-040.
Freezing Rain Advisory until 5 AM EST Saturday for WVZ516-518-
521.
OH...Freezing Rain Advisory until 5 AM EST Saturday for OHZ083>086.
Freezing Rain Advisory until 7 AM EST Saturday for OHZ066-067-
075-076.
KY...None.
VA...None.
&&
$$
SYNOPSIS...TRM/MPK
NEAR TERM...TRM/30
SHORT TERM...MPK
LONG TERM...MPK
AVIATION...30
Area Forecast Discussion
National Weather Service Blacksburg VA
912 PM EST Fri Dec 16 2016
.SYNOPSIS...
Arctic high pressure over the region will shift east and offshore
overnight ahead of a complex low pressure system that will pass
well to the west over the weekend. A warm front associated with
the low will approach the region from the southwest Saturday and
pass to the north Saturday night. A trailing cold front will then
slide east across the area on Sunday, reaching the coast Sunday
night into Monday.
&&
.NEAR TERM /THROUGH SATURDAY/...
As of 850 PM EST Friday...
Satellite loops and observations show low level moisture
continuing to slowly edge up from the south as seen via lowering
cloud bases heading across the NC/VA border counties attm. However
soundings and subsequent dewpoints indicate a swath of very dry
air from the surface to 850 mb with humidity levels still below
40-50 percent in most spots. Expect this to continue to delay the
onset of much freezing drizzle or spotty freezing rain until about
midnight, mainly southeast sections where the return axis of low
level moisture under deeper warm advection aloft looks a bit
better. This supported by the latest HRRR which brings a lobe of
light precip into the southeast counties, mainly from MTV to LYH
and points east in the next few hours, while other solutions
including the RAP/HRRRX show much less until late over the
northwest where deeper moisture will reside by daybreak.
Therefore already cut back on pops early on espcly north before
going with mostly chance pops all sections into the early morning
hours which may be generous.
Although the RNK evening sounding remains below freezing aloft,
ongoing very strong warm advection aloft should quickly develop a
larger warm nose above per GSO raob, with this warming reaching
the surface on Saturday. Thus leaving out any snow/sleet mention as
still appears the best chance will be for very low QPF light
icing over the southeast, and far northwest with perhaps only
spotty if any in between. Southwest winds may also be an issue
toward daybreak on the ridges as the inversion lowers and the
depth of the warm air increases. However appears given such a
deep/cold airmass to scour out that will have less chance of
mixing down except over the far west where added a mention to the
HWO into Saturday. Otherwise updated temps to reflect a bit colder
start to initialize but already seeing some slight rises which
should increase overnight with a nondiurnal curve on track.
Previous discussion as of 348 PM EST Friday...
Sprawling high pressure area over eastern Virginia extends a
ridge back from it into the southern Appalachians. Temperatures
remain quite chilly with readings mainly in the 20s, and the low-
level airmass remains extremely dry as seen in current dewpoints
and this morning`s 12z RNK/GSO RAOBs. Those conditions will set
the stage for light wintry weather tonight with light ice
accretions producing some impact for our area. Hence, freezing
rain advisories have been issued for most of our counties except
for Smyth and Tazewell in Virginia.
For tonight into early morning Saturday...strong southwesterly
warm advection takes place aloft on 850 mb winds nearing 50 knots,
with 850 mb temperatures pushing above +3C by the time
precipitation starts and will only continue to rise aloft as the
overnight and early morning progresses. Via the top- down
methodology, +3C is usually sufficient to fully melt any light
precipitation that falls, but will only re-freeze in the shallow
cold air (temps in the 20s to around 30). I stuck mainly with the
GFS thermal profiles. Given how dry the airmass is, freezing
rain/freezing drizzle will probably be fairly intermittent and not
steady. In fact icing amounts are barely a couple hundreths and
feel in most cases will be a trace; as such, PoPs were kept low.
But the impact will be the same, and that is mainly for slippery
roads and sidewalks overnight tonight. Surface temperatures warm
above freezing earliest in Smyth and Tazewell counties and the
duration of any freezing precipitation is limited. Elsewhere,
surface temperatures project to rise above freezing into the early
Saturday morning hours. After collaboration with surrounding
offices, the freezing rain advisory begins at 7 pm for northwest
NC and the VA foothills and southside, and at 10 pm for the rest
of the advisory area. The overall message, however, is that
precipitation amounts will be very light but should result in
slippery roadways and sidewalks.
Regarding winds...Southwesterly winds stand to increase as well and
should get gusty across the higher summits; but even in these areas
wind speeds should stay below Advisory criteria.
Temperatures tonight are largely non-diurnal and given the
retreating modified Arctic airmass, the low has already been met in
a few places. But lows temps in the 20s will rise to the upper 20s
to low 30s by morning, except mid 30s in the Mountain Empire.
As is typically the case in leftover cold air damming scenarios, the
question becomes for late morning Saturday into Saturday afternoon
on how quickly does the lingering "cool" air get scoured out, which
should have an influence mainly on the high temperature forecast for
Saturday. Given that there isn`t rain falling into the airmass and
the strength of southwesterly wind fields, temperatures should warm
into the upper 40s east of the Blue Ridge as the CAD erodes. The 850
mb temps would support higher values but I sided a little on the
colder end of guidance owing to likely persistent overcast. West
of the Blue Ridge, temps should warm into the mid 50s.
&&
.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY NIGHT/...
As of 348 PM EST Friday...
A sharp upper level trough will push a surface wave across the Ohio
Valley Saturday night to New England on Sunday. The eastward
movement of the front will be slow, stalling across the southern
Ohio Valley into the Tennessee Valley Saturday night, then finally
moving across the southern Appalachains on Sunday. A secondary
surface wave develops along the front Sunday afternoon over the
piedmont of North Carolina. While this wave is forming, the front
and associated showers will stall over the area. By late Sunday
evening, both the front and showers will move out of Southside VA.
Rainfall amounts Sunday will range from a quarter to half /0.25-
0.50/ of an inch. The front will continue to move slowly to the
coast Sunday night and Monday. High pressure will follow the front,
then remains over the region through the better part of next week.
We can expect a wide range in temperatures Sunday with cold air
banked up against the western slopes of SE WV/SW WV while the east
remains in the warm sector. Temperatures will range from the lower
40s across the Greenbrier Valley to near 60F in Southside VA. With
the cold front south of the forecast area Monday, high temperatures
will be 10F cooler than normal ranging between 30F to 40F.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
As of 348 PM EST Friday...
High pressure remain over the region into Wednesday night.
Temperatures will moderate each day with Monday being 10F below
normal and around 5F above by Wednesday. The northern and southern
jet streams remains out of phase with most of next week being warmer
than normal and dry. The next chance for widespread rain may not
come until next weekend.
&&
.AVIATION /02Z SATURDAY THROUGH WEDNESDAY/...
As of 600 PM EST Friday...
VFR should prevail across the region through the evening with
cloud bases slowly lowering as low level moisture starts to
increase. Thereafter ceilings look to quickly lower as deeper
warm advection on a very strong jet aloft begin to interact with
increasing moisture advection. This should result in mainly MVFR
cigs developing after midnight most spots, with some spotty
freezing rain or freezing drizzle possible mainly around KDAN and
across the northwest near KLWB during the early morning hours.
However confidence quite low given so much dry air in place and
model tendency espcly the Nam in bringing return low level
moisture too far west. Thus trending toward the drier GFS and
latest HRRR in only including a precip mention at the two above
sites late.
Warming temperatures should allow for any residual freezing
rain/drizzle to transition to a cold rain by mid-morning Saturday,
with only very light icing amounts possible. A period of IFR may
also occur early Saturday espcly at sites along/east of the Blue
Ridge where a lobe of low level moisture will swing up from the
south early on before exiting. However MVFR ceilings will persist
through much of the rest of the TAF period, with possible periods
of VFR along the KBLF-KBCB-KROA corridor where could end up in a
small dry slot between deeper moisture to the northwest, and low
clouds to the south/east. Expect most rainfall to taper off by
afternoon with only spotty showers possible over the northwest for
the most part during Saturday afternoon.
Winds will begin to steadily increase aloft this evening and
eventually near the surface by early Saturday. However the speeds
will increase faster aloft and support a period of potential low
level wind shear after midnight, with the exception of KBLF where
should see enough surface gustiness to preclude any LLWS mention.
Surface winds begin light southeast but veer to south and
increase to 5-15 kts by Saturday, with gusts to 30+ kts perhaps
developing at KBLF Saturday morning.
Extended aviation discussion...
Although rainfall will be limited Saturday night ahead of the cold
front approaching from the west, still expecting overall MVFR cigs
overnight with ocnl IFR possible where patchy fog/stratus take
shape.
Deterioriating conditions will occur from west to east on Sunday
as the surface cold front drives east with ana front type precip
trailing the boundary much of the day. This should bring
widespread MVFR/IFR cigs/vsbys to the mountains for most of Sunday
with cigs/vsbys lowering across the east as the rain arrives by
afternoon. The rain may change to a mix or wet snow before ending
across KLWB/KBLF later Sunday with perhaps some of this making out
to the Blue Ridge locations by evening just as the rain ends. MVFR
ceilings and visibilities are likely in the mountains Sunday night
within the post frontal northwest flow regime overnight.
Conditions will improve for Monday through midweek as dry high
pressure builds into the Mid Atlantic region.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...Freezing Rain Advisory until 9 AM EST Saturday for VAZ010>014-
018>020-022>024-034-035-045>047-059.
Freezing Rain Advisory until 9 AM EST Saturday for VAZ015>017-
032-033-043-044-058.
NC...Freezing Rain Advisory until 9 AM EST Saturday for NCZ001>006-
018>020.
WV...Freezing Rain Advisory until 9 AM EST Saturday for WVZ042>044-
507-508.
&&
$$
SYNOPSIS...AL/JH
NEAR TERM...AL/JH
SHORT TERM...RCS
LONG TERM...RCS
AVIATION...AL/AMS/JH
Area Forecast Discussion
National Weather Service Shreveport LA
830 PM CST Fri Dec 16 2016
.UPDATE...
To the overnight low temperatures and remove afternoon wording.
&&
.DISCUSSION...
Warming this evening with gusty Southerly winds. Peak gusts are
still running in the mid to upper twenty mph range for Shreveport
and much of NE TX. Farther East, gusts are around 20, but may
peak out more in the coming hours. We have updated hourly
temperature grids with HRRR to better reflect the current chill
still North of I-30 give or take, as this warm front will clear
all of the area by daybreak. Lufkin has just warmed to 69 and
needs an update to this update. We will watch the winds for a few
hours and check temps again in a bit. The HRRR has sporadic low
70s along and South of I-20 by daybreak. Our evening sounding had
SW at 60KTS near 15 hundred feet. Wow! The moisture is still
pretty shallow only saturated to near 5kft. Super dry above, but
the clouds and fog and drizzle will transistion to a few showers
as the moisture continues to deepen overnight. /24/
&&
.PREV DISCUSSION... /issued 556 PM CST Fri Dec 16 2016/
AVIATION...
Very poor flying conditions will best describe this forecast as we
go through the next 24 hours. Starting off this evening with a
mixed bag of ceilings...ranging from MVFR conditions across
Northeast Louisiana to LIFR conditions across portions of
Northeast Texas. Also hampering observations is the presence of
drizzle which at times is causing a reduction in visibility to
near 1/4 mile at times across Northeast Texas...this despite the
fact that strong south winds are gusting upwards of 27kts at the
TYR airport. Expecting similar conditions overnight with in and
out drizzle across all area terminals which could reduce vsbys
quickly. MVFR ceilings will at the very least become IFR across
our eastern terminal locations and in and our LIFR ceilings as
well with in and out drizzle.
Hopefully we will see a break from the drizzle on Saturday but
will be difficult to break at IFR ceilings through much of the
morning into the afternoon. Showers and thunderstorms appear to
get going along a strong cold front just to the northwest of our
terminal sites near or just after the 18/00z timeframe. Winds will
remain 10-15kts areawide tonight with higher gusts across or NE
TX terminals with all terminal locations getting in on gusty south
to ssw winds during the day Saturday...much stronger across NE
TX.
13
PREV DISCUSSION... /issued 320 PM CST Fri Dec 16 2016/
DISCUSSION...
.Much to discuss for the near term forecast as it is plagued
with windy conditions, severe weather and chilly conditions...
Synoptic pattern is comprised of near zonal flow aloft across the
Four-State region and most of the U.S. for that matter, whilst an ul
trough commenced to impinge on northern CA late this aftn. Sfc
cyclogenesis on the lee of the Rockies/Southern Plains has promoted
sfc serly flow across the FA, leading to temps capable of rebounding
into the 50s for most of the CWA per 21Z metars despite the
persistent stratus deck. In addition, this upslope sfc regime has
resulted in the nwrd translation of Gulf moisture with dewpoints
increasing some 15-20 degrees since 8 am CST this morning. These
warm and moist conditions overrunning a cold sfc is responsible for
the drizzle/light rain showers across portions of the ARKLATEX.
As the Southern Plains sfc low ejects east to across the lower
Mississippi Valley later this aftn-tonight, its tightened pressure
gradient will allow for southerly wind speeds to increase into the
15-25 mph range, across portions of east TX, deep east TX, southeast
OK, northwest LA and southwest AR. In fact, wind speeds of 15-17 mph
noted across east TX late this aftn, hints at this gradient
starting to tighten. The Lake Wind Advisory will therefore remain
in effect from 4 pm today through 6 am CST Saturday morning, hence
when the gradient relaxes.
Thereafter, the ul trough is poised to push southeast across the
Desert southwest tomorrow morning, the Southern Plains late tomorrow
aftn/early evening and to across the Four-State Region tomorrow
night/early Sunday morning where it will wane shortly thereafter.
This disturbance will be accompanied by a strong cold front which is
being driven by a 1040 mb sfc ridge. Pressure rises on the order of
5-10 mb per 3 hours is suggestive of northerly wind speeds of 20-30
mph with higher gusts. This will initially affect locales across
southeast OK and northeast TX aoa 18/03Z and spread southeast to
across northwest LA throughout tomorrow night. These wind speeds
definitely fit within the criteria of Lake Wind Advisory so
another issuance may be required in the near future. So with the
front not expected until after sunset on Saturday, we will see one
more warm day /60s and 70s/ before the strong CAA arrives. In
addition to breezy conditions, the front will also be a focus for
scattered showers and thunderstorms, with the majority of model
solutions indicating the precip activity evolving into somewhat of
a line stretched from portions of deep east TX to across north
central and northeast LA tomorrow evening through the overnight
hours. PWATS increasing to 1.20-1.60 inches across the
aforementioned areas coupled with excellent frontogenetical
forcing, increased ul support and 0-6 km bulk shear in excess of
60 kts suggests some of the storms being capable of reaching
strong to possible severe levels particularly across portions of
central, north central and northeast LA into southwest AR.
Damaging wind gusts and brief moderate rainfall will be the
primary threats however, veering wind profiles and curved low
level hodographs raise concern for isolated tornadoes across the
aforementioned area. It is no wonder the Storm Prediction Center
has a slight risk of severe storms stretched from Sabine county
northeast to Union county and locales south and east. A marginal
risk exists for Caddo and Bossier parishes but keep in mind, this
means there is only a 5% probability for this occurrence.
Saturday night-early Sunday morning, the CAA will slowly ooze in,
which will drop temps into the 20s northwest to upper 30s southeast.
Before all the low level moisture gets squashed by the cold front
and accompanied drier air, there is a brief period for perhaps light
rain mixed in with freezing drizzle and/or flurries across southeast
OK, southwest AR and extreme northeast TX. Do not expect hazardous
conditions to occur on roadways and structures as accumulations are
expected to be little to none. Temperatures will be slow to warm as
we head into early next week /daytime temps in the 40s on Monday/,
but the return of srly sfc flow by mid-week will aid to increase
temps into the 50s.
29
&&
.PRELIMINARY POINT TEMPS/POPS...
SHV 64 77 31 36 / 30 30 60 10
MLU 58 79 34 37 / 40 30 80 20
DEQ 46 69 23 31 / 20 30 30 0
TXK 54 75 25 34 / 30 30 40 10
ELD 58 76 29 34 / 40 30 70 10
TYR 64 76 24 34 / 20 30 40 0
GGG 63 77 27 35 / 30 30 50 10
LFK 67 78 33 38 / 30 30 60 10
&&
.SHV WATCHES/WARNINGS/ADVISORIES...
AR...Lake Wind Advisory until 6 AM CST Saturday for ARZ050-051-
059>061-070>073.
LA...Lake Wind Advisory until 6 AM CST Saturday for LAZ001>006-
010>014.
OK...Lake Wind Advisory until 6 AM CST Saturday for OKZ077.
TX...Lake Wind Advisory until 6 AM CST Saturday for TXZ096-097-
108>112-124>126-136>138-149>151.
&&
$$
24/13/29