Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 03/02/23
Area Forecast Discussion
National Weather Service Columbia SC
1052 PM EST Wed Mar 1 2023
.SYNOPSIS...
A front will slip south into the region on Thursday and stall.
This will provide a chance of showers, and possibly isolated
thunderstorms. Another cold front, and associated band of
showers and possible thunderstorms is expected Friday afternoon
and evening. Warm and windy as well Friday. The front will
slowly move off the coast Friday night and Saturday, then dry
high pressure will settle into the region Sunday and Monday. A
front and increased moisture will move into the region Tuesday
and Wednesday.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
Skies are partly to mostly cloudy across the forecast area this
evening. While regional radar imagery is picking up some light
echos around the CWA, surface observations do not indicate any
rain is reaching the ground at this time. Rain chances should be
low through the evening before increasing after midnight when a
shortwave will approach from the west. This disturbance will
combine with PWATs generally in the 1.25" to 1.5" range to
produce isolated to scattered showers. The best chance of rain
will be areas north and west of I-20 which are closer to the
upper-level support. Most locations that do see rain tonight can
expect amounts at or under a tenth of an inch. The exception to
this will be over our far northern counties, especially the
panhandle of Lancaster County. The clouds and rain will limit
nocturnal cooling with lows in the lower to mid 60s, holding
steady or increasing towards daybreak.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH FRIDAY NIGHT/...
Models bring the cold front, and a band of high PW, towards our
northern forecast area (FA) Thursday. Latest high resolution
models suggest the main frontal boundary, or a prefrontal trough
or boundary related to upstream convection, will slip farther
south and also provide a focus for showers and isolated
thunderstorms Thursday afternoon and evening farther south into
the remainder of the FA. The front is expected to lift north as
a warm front Friday morning ahead of the next weather feature.
The main concern for the forecast period continues to be Friday. The
upper low, and associated intensifying surface low, is progged to
shift NE across the Ohio Valley/Central Appalachians region
Friday/Friday night, bringing a cold front into our FA.
Guidance continues to indicate strong shear and weak to possibly
moderate instability, which provides a severe weather concern
along or ahead of the front. Latest guidance trending towards
slower timing of the main front, and therefore later timing with
the warm front lifting up through the NE FA ahead of it, which
could affect max temps NE FA. Timing of the threat of severe
weather uncertain as the convective line may move out ahead of
the main front. SPC has highlighted our region in a Day 3 (Fri)
SLGT risk for severe weather. Guidance indicating breezy to
windy conditions as well Friday, which may necessitate at least
a Lake Wind Advisory, possibly a general Wind Advisory, with max
wind gusts over land areas up to 40 to 45 mph, a little lower
over cooler area lakes. Strong SSW low level flow and associated
warm air advection will provide very warm temps south of the
warm front. The cold front is expected to slowly push south of
our FA towards the coast late Friday night.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
The latest guidance pushes the front slowly offshore Saturday,
with drier air entering our region, as an upper trough shifts to
the east coast by Sunday, with surface high pressure building
into our region Sunday and Monday.
GFS/EC ensemble means generally indicate upper trough near the west
coast with an upper ridge over the central CONUS/Miss Valley region,
and an upper trough off the east coast early next week. They
indicate a strong cold high pressure center over Canada and a
cold front slowly approaching our region Tue/Wed time frame with
some moisture return, with temps trending lower.
&&
.AVIATION /04Z THURSDAY THROUGH MONDAY/...
High probability of MVFR by 12z Wednesday...but improving
ceilings mid to late morning.
Weak surface boundary just north of the CAE terminal area.
Ceilings mid level and expect this trend to continue into the
late evening with scattered lower clouds. Some mixing in the
boundary layer expected overnight, however with 35-40kt
southwest jet at 2000 ft indicated by models, put low level wind
shear through 12z. Low level moisture increases by 12z. HRRR
and NBM suggest MVFR ceilings through the morning...then mixing
out. Expect scattered showers mainly northwest of the terminals
through the morning then possibly moving into the area in the
afternoon. Southwest winds 10 to 15 knots with higher gusts
possible then becoming 10 knots or less in the afternoon and
variable. High resolution models show scattered showers
mainly in the afternoon.
EXTENDED AVIATION OUTLOOK...Restrictions possible Thursday night
with continued high low-level moisture. A strong cold front
will cross the region Friday with increasing confidence in
restrictions and potential for strong thunderstorms.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
GA...None.
SC...None.
&&
$$
Area Forecast Discussion
National Weather Service Duluth MN
524 PM CST Wed Mar 1 2023
.DISCUSSION...(This evening through Tuesday)
Issued at 301 PM CST Wed Mar 1 2023
Summary: Snow tapering off this evening as we head into a quieter
period.
The deformation area of a filling area of low pressure crossing
into Wisconsin this afternoon is straddling the Twin Ports giving
moderate to heavy snowfall rates. The heaviest snowfall band
associated with this low has stopped its northward progression and
has started diving south back towards the Twin Ports. The
expectation is that it will lighten up and dissipate as the low
exits early this evening, but will likely give another inch or two
to the Twin Ports. Rapid warming of cloud tops on IR near the
Twin Ports, indicates that the system is moving away quickly and
lift is decreasing. But for now, radar still depicts heavy
snowfall rates in areas that reside in a saturated DGZ layer with
decent omega as depicted on the SPC Mesoanalysis page which will
give rapid accumulations with High SLR`s. Model guidance
decreases snowfall rates rapidly this afternoon, but each
successive HRRR run seems to be trying to catch up with the
current radar meaning models have been trying to stop the snow too
soon. I still like the warming cloud tops as a good indicator
that we`re near the end especially as the surface low has begun to
rapidly move east. While NW WI is seeing a decent batch of
snowfall at the moment, expect that to wane too, but a couple of
additional inches are still possible. Did expand the Warning
northward along the North Shore mainly to cover the potential to
exceed 6" there for areas south of Two Harbors with that heavy
band. Holding off an upgrading NW WI just because the reports
there haven`t been too significant from what we`ve heard from
spotters.
After this evening, the remainder of the forecast, is fairly
quiet. A large low pressure does move through Michigan on
Saturday, but it looks like we`ll miss out on any snowfall fun
from this one. There are some indications of a similar system on
Monday (to the current one) of next week, but again like this one,
it doesn`t look too impressive at the moment. The area stays in
about normal temperatures through the forecast period.
&&
.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
Issued at 523 PM CST Wed Mar 1 2023
Snow is slowly starting to wane across the region this evening with
a few bands of snow near the Twin Ports and NW WI slowly weakening.
Ceilings are largely IFR with a few areas already coming back up to
MVFR. Ceilings should be trending up through the overnight period
with an eventual return to VFR around midnight. HYR however may see
lower ceilings lingering beyond midnight. Tomorrow, winds will be
lighter with winds out of the south, some MVFR clouds may enter from
the west in the afternoon and evening.
&&
.MARINE...
Issued at 301 PM CST Wed Mar 1 2023
Strong northeast winds form this system will cause hazardous
conditions on western Lake Superior into Thursday. Things quiet
down for awhile until Monday when northeast winds pick back up.
&&
.PRELIMINARY POINT TEMPS/POPS...
DLH 4 26 15 34 / 50 0 0 0
INL -8 27 15 36 / 0 0 0 0
BRD 1 27 17 36 / 10 0 0 0
HYR 8 32 16 39 / 50 0 0 0
ASX 10 30 13 39 / 80 0 0 0
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
WI...Winter Weather Advisory until 6 PM CST this evening for
WIZ001>004-006>009.
MN...Winter Weather Advisory until 6 PM CST this evening for MNZ012-
019.
Winter Storm Warning until 6 PM CST this evening for MNZ020-037.
LS...Small Craft Advisory until 9 PM CST this evening for LSZ140>142-
148.
Small Craft Advisory until 2 AM CST Thursday for LSZ143>146.
Small Craft Advisory until 6 AM CST Thursday for LSZ147-150.
&&
$$
DISCUSSION...Wolfe
AVIATION...Britt
MARINE...Wolfe
Area Forecast Discussion
National Weather Service Des Moines IA
539 PM CST Wed Mar 1 2023
...Updated for the 00z Aviation Discussion...
.DISCUSSION.../Tonight through Wednesday/
Issued at 321 PM CST Wed Mar 1 2023
Key Messages:
-- Trend southeastward with wintry precipitation late Thursday
night/Friday; blustery
-- Low precipitation chances this weekend into early next week
Details: Surface and 500mb low passed north of Iowa this morning
bringing gusty breezes into the state, which are continuing this
afternoon over northern Iowa. The clear sky this morning gave a good
view of the current state of our snowpack, which over central Iowa
remains up across portions of Palo Alto, Emmet, northern Kossuth,
Winnebago, and Worth counties. Low clouds rotated back into the
northern part of the state on the backside of the departing low
while mid and high level clouds are just beginning to stream into
far western Iowa.
Our main focus is on the Thursday night and Friday system.
Currently, this system is a positively tilted trough over southern
California, which will quickly move into the southern Plains before
lifting northeastward and taking on a negative tilt across
Missouri into Illinois on Friday. During this lifting phase, the
6z/12z deterministic models show a deepening of the surface low
with the 0z NAEFS and ECMWF ensembles continuing to show a minimum
percentile surface low tracking south of Iowa. The 6z/12z NAM and
0z ECMWF continue to favor a more northern track while the 12z
ECWMF, 0z/12z CMC, and 0z/12z GFS all favor a track farther
south. The 12z ECMWF still is north of the GFS/GEFS and
CMC/ensemble, but a trend to the southeast has now been shown. 18z
HRRR and 12z HREF surface pressure are also favoring a southern
track. Thus, with this preponderance of data, our forecast has
started to pivot PoPs/QPF toward the southeastern part of the
state. If the 18z HRRR was taken at face value, it would suggest
no precipitation at all for Iowa. For now, still will carry PoPs
over the southern and eastern forecast area with token PoPs as
far northwest as a Bedford to Des Moines to Waterloo line. If
trends continue south and east, this will be pushed farther
southeast. Precipitation type will vacillate from rain to snow and
perhaps back to rain before ending since we may not be as close
to the better dynamics. Minor snow accumulations will be possible
with our current forecast over southeastern Iowa topping out at 2
to maybe 3 inches, though this could change depending on
forthcoming model data. As also discussed yesterday, high pressure
over southeastern Canada will be advecting in dry air on easterly
winds and this has delayed the initial precipitation onset in our
forecast area by about 12 hours. Further, a rapid dropoff in the
precipitation shield to the north is anticipated. With the favored
solution being southern, our blustery winds look to remain below
wind advisory criteria as well.
With the current expected southern track of the Thursday night/
Friday system, this does open the door for a few additional, but low
chances of precip this weekend into early next week as the
shortwave train tracks closer to the state. The first will be
later Saturday into Saturday night as a fast moving shortwave
moves across the region. Forecast is dry for now as forecast
soundings show saturation to be marginal and short-lived at best.
Another shortwave arrives toward Sunday night with better
moisture reflected in the soundings and stronger QG convergence
and low level thermal lift. Thus, low precipitation chances are in
the forecast from Sunday night into Monday. Given current GFS
thermal profiles with low level warm air, much of this could fall
as rain.
&&
.AVIATION.../For the 00Z TAFS through 00Z Thursday evening/
Issued at 540 PM CST Wed Mar 1 2023
Weak cold front into southeast Iowa now with lowering MVFR/IFR
cigs prior to high pressure helping to improve cigs to VFR aft 14
to 17z as trough pulls east and high builds into region. Winds
remain brisk with gusts gt 20kt; especially MCW, ALO. Finally aft
11z, winds relax to under 12 kts all locations and continue to
remain light through 00z as east flow returns. /rev
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
DISCUSSION...Ansorge
AVIATION...REV
Area Forecast Discussion
National Weather Service Lubbock TX
531 PM CST Wed Mar 1 2023
...New AVIATION...
.SHORT TERM...
(This evening through Thursday)
Issued at 222 PM CST Wed Mar 1 2023
19Z upper air analysis depicts a compact vorticity lobe positioned
over the southern Sierra Nevada Mountains, with a baroclinic leaf
materializing across the southern Great Basin. Broadly anticyclonic
flow exists to the east of this amplifying shortwave trough, where a
belt of high-level moisture originating from the northeastern
Pacific Ocean continues to advect northeastward over the higher
terrain of Chihuahua and into the CWA. The edge of the cirrus deck
is delineated along a line roughly from Bledsoe-to-Amherst-to-Tulia,
becoming almost entirely clear across Parmer County where sheared
cirrus debris exists along the northwestern periphery of the deck.
At the surface, an expanding anticyclone at around 1014 mb was
located across west-central Kansas, where winds have veered to the
east and southeast across the Rolling Plains and Caprock,
respectively. The weak, cold air advection in addition to the dense
overcast, which has limited the extent of diabatic heating and
therefore delayed the onset of efficient vertical mixing, has
resulted in cooler temperatures persisting into the early afternoon
hours. Winds will continue to veer over the next few hours, becoming
southwest by mid-afternoon (20-21Z) while increasing to 15-25 mph
through sunset across locations along and west of the I-27/HWY-87
corridors before diminishing entirely upon the cessation of vertical
mixing. Temperatures should respond in tandem with the southwesterly
fetch, albeit small, with highs peaking in the lower-middle 70s
across the southern zones and into the middle 60s towards the
extreme southern Texas Panhandle heading into the late afternoon
hours. Recent West Texas Mesonet and regional METAR observations
support this prognostication, and the official forecast grids have
been adjusted to align with the HRRR to best capture these trends in
observations. Due to the very narrow window of breezy, southwesterly
winds; and dense overcast, the Red Flag Warning will be canceled for
all counties except the western column (Parmer-to-Yoakum Counties).
A short-fused Fire Danger Statement will be issued for the rest of
the South Plains through 02/01Z.
Overnight, the aforementioned anticyclone over west-central Kansas
will continue to translate to the northeast, while the cirrus deck
shifts to the east. The combination of light, southwesterly winds
and the gradual clearing of the cloud deck will foster recovery of
relative humidity to around 40 percent across the Caprock, and into
the middle 60s across the northeastern Rolling Plains. By 02/12Z,
the closed, mid-level circulation and neutrally-tilting trough is
forecast to be positioned south of the Four Corners region, with a
north-south oriented Pacific cold front propagating across the
southern Rocky Mountains and into the southwestern High Plains.
Surface winds will increase accordingly after sunrise as leeward
pressure falls associated with the compacting isallohypsic gradient
intensify, with a 996 mb surface cyclone expected to form in the
Texas Panhandle along the northern flank of the eastward-advancing
cold front. This will generate a strong isallobaric response at the
surface across the Permian Basin and into the southern South Plains,
and with near-dry-adiabatic surface-to-3-km lapse rates evolving due
to magnitude of the geopotential height falls and vertical depth of
the Pacific front amidst the presence of a 35 kt 850 mb jet stream,
a high wind event is forecast to develop tomorrow afternoon across
the southwestern and southern South Plains with the possibility of
advisory-level winds extending into the central South Plains.
Moist, isentropic ascent is also expected to be largely displaced to
the south and east of the CWA; and with an already well-mixed
boundary-layer present, along with no other source of low-level
moistening expected, PoP chances remain confined to the southeastern
Rolling Plains where WAA-induced rain showers may be able to
penetrate the Inverted-V profile. A rogue, dry microburst will be
possible, though updrafts will struggle to reach heights high enough
to generate lightning as the stout subsidence inversion remains in
place ahead of the front before mid- and high-level flow backs. The
net result of the backing flow atop the post-frontal airmass will
result in a large field of difluent flow, with deformation banding
possible along the backside of the ejecting cyclone followed by a
secondary cold front to move through the CWA from the north.
Sincavage
&&
.LONG TERM...
(Thursday night through next Tuesday)
Issued at 222 PM CST Wed Mar 1 2023
Thursday evening opens with the upper low lifting across the
southern South Plains before deepening as it becomes negatively
tilted overnight in North TX. Strong westerly winds over the
southern half of our CWA will gradually wane as mixing ceases;
however, there remains a window for occasional advisory winds
later in the evening on the heels of a northern cold front.
Pressure rises and the magnitude of CAA aren`t very noteworthy for
widespread 30+ mph sustained winds, yet the NBM90 still looks
more fitting with a few locales hitting advisory speeds until the
gradient eases after midnight.
Precip-wise, we still expect at least a loosely organized
deformation zone to emerge across our NW zones early Thursday
evening before translating ESE overnight with the departing H7 and
H5 lows. The big negative remains the pre-existing dry slot which
should wrap around a large portion of the mid-level low before
Thursday evening, but with time saturated ascent should overcome
this drying and yield some measurable precip, mainly over our
northern zones. NBM is on board with milder vertical profiles
tomorrow evening and soundings are not as aggressive with wet
bulb cooling in the lowest 3k feet. HREF is one exception to this
and continues to expand the rain-to-snow transition as far south
as Lubbock toward midnight, but this is an outlier for now. Very
light snow accumulations were shaved back to our far NW zones
where temps are closest to 32. Once precip and clouds exit later
in the night, lows on the Caprock should fall off into the 20s and
lower 30s.
Seasonal temps close out the week under increasingly zonal flow
which remains largely intact through early next week. Barring a very
weak cold front late Friday night into early Saturday courtesy of a
minor impulse cresting the central Rockies, mild SW breezes should
be the rule with temps returning to above normal territory by
Sunday. The next boundary of any concern looks to make an appearance
o/a Tuesday in the form of a backdoor cold front, but continued dry
and uneventful westerly flow aloft won`t offer any hope for precip.
&&
.AVIATION...
(00Z TAFS)
Issued at 527 PM CST Wed Mar 1 2023
Another storm system will approach the South Plains area from the
west Thursday afternoon. Relatively light winds ahead of the
system tonight due to the remnants of a weak cold front lingering
across the forecast area will switch to the west-southwest and
increase markedly at KLBB and KPVW late morning behind a strong
Pacific cold front. Further northeast of the system at KCDS winds
will back to north as the front approaches. Some restriction to
visibility due to blowing dust will be possible, mainly at KLBB
where winds are expected to be the strongest.
&&
.FIRE WEATHER...
Issued at 222 PM CST Wed Mar 1 2023
Critical fire weather conditions are expected across the western
South Plains this afternoon and evening, while near-critical to
elevated conditions are expected elsewhere across the rest of the
South Plains. A Fire Danger Statement will replace the other
counties previously in the Red Flag Warning. Surface winds continue
to veer to the southwest, and temperatures have responded
accordingly and will rise into the lower 70s across most of the
South Plains. A few hours of elevated-to-critical fire weather
conditions will develop as winds fully transition to the southwest
through late afternoon. Relative humidity values are forecast to
fall into the upper single-digits this afternoon in tandem with the
warmest temperatures and peak winds.
A strong, Pacific cold front will move through the region late
tomorrow morning. Winds will shift to the west in its wake with a
high wind event possible across most of the southern South Plains.
Sustained, westerly winds between 30-40 mph with gusts up to 60 mph
are forecast, though temperatures will be quite cooler which will
keep minimum RH values in the upper teens to lower 20 percent range.
Excellent vertical mixing is expected post-frontal passage across
the Caprock and Rolling Plains. Another cold front will move through
the region from the north near sunset, shifting winds to the north
and remaining blustery overnight with RH recovery above 80 percent.
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
Red Flag Warning until 7 PM CST this evening for TXZ021-027-033-
039.
Fire Weather Watch from Thursday morning through Thursday
afternoon for TXZ027>031-033>044.
High Wind Watch from Thursday morning through Thursday evening
for TXZ033>036-039>042.
&&
$$
SHORT TERM...09
LONG TERM....93
AVIATION...07
Area Forecast Discussion
National Weather Service Midland/Odessa TX
518 PM CST Wed Mar 1 2023
...New AVIATION...
.SHORT TERM...
(This afternoon through Thursday night)
Issued at 314 PM CST Wed Mar 1 2023
*Significant Wind Event Thursday*
Current 500mb RAP analysis shows brisk southwesterly flow of about
70-80kts squeezed between the subtropical ridge in the
Caribbean/Gulf of Mexico and a digging trough across California.
This trough quickly swings through the Desert Southwest tonight and
is progged to be move overhead tomorrow afternoon/evening. Winds
increase today, largely across the higher terrain with mountain wave
signatures setting up across the Guadalupe and Davis Mountains,
remaining elevated out west tonight as the trough approaches. Cloud
cover has largely limited mixing the strongest possible gusts down
so far this afternoon outside of the mountains.
Models have started to come into general agreement with the
aforementioned trough as it swings through, staying slightly
positively titled overhead tomorrow, with the center of the low
tracking over our shared border with Lubbock. This is roughly a
100mi shift southward in the track since yesterday, with the trough
being deeper and a bit slower. This places the 500mb jet (of ~90 to
110kts) across a large portion of our area, with the strongest winds
located south of I-10. A Pacific front will accompany this system,
now set to move into the western zones around 14-15z tomorrow
morning, pushing eastward through the Permian Basin through 18-21z.
The stronger winds aloft will be tapped into behind the front, with
some of the strongest winds focused with FROPA. One major concern is
directional shear present given the timing of the trough with more
south-southwesterly winds aloft with westerly surface winds behind
the trough. This is less of an issue further south, especially
across the Big Bend and higher terrain which is where the strongest,
possibly damaging winds gusts are expected. With this, the High Wind
Watch has been upgraded for all zones except the northern and
easternmost counties in the Permian Basin. Additionally, with such a
fetch of strong winds being the Pacific front, a large swath of
blowing dust may accompany it. Am not as confident in seeing what
was seen with Sunday`s event due to the front moving through
somewhat earlier than Sunday, though some widespread blowing dust is
still possible.
After a warm, downsloping day today, cooler air ahead of the Pacific
front sends lows into the mid 30s to low 40s along the far western
zones with another mild night elsewhere, lows stay the upper 40s and
50s. As the Pacific front pushes through tomorrow, a few rain and
snow showers are possible across the Guadalupes along with a few
showers for the far eastern Permian Basin. Within all of this
weather, very dry conditions are expected to develop between a
prefrontal trough and the Pacific front, setting up yet another day
of critical to extreme fire weather tomorrow. See the Fire Weather
Discussion below for more details.
-Munyan
&&
.LONG TERM...
(Friday through Tuesday)
Issued at 314 PM CST Wed Mar 1 2023
A much calmer weather pattern is ahead this weekend into early next
week and forecasters here are thankful for that! Zonal mid level
flow through the weekend will keep the weather fairly consistent.
Temperatures warm Friday into the 60s to near 70 with generally
light winds. A weak cold front will slip into the region Saturday,
but do little to affect the overall weather. Southerly flow
returns Sunday and begins a period of above normal temperatures
that will last into midweek. Lows will generally be in the 40s/50s
with highs in the 70s/80s. Precipitation chances stay at zero,
but with lighter winds, fire weather concerns will be low. Long
range models are in agreement that a front will arrive sometime
midweek. What is not in agreement is how cold the airmass behind
the front will be. The NBM is showing a fairly wide SD in
temperatures once we get to Wednesday and Thursday. We will be
monitoring as winter may not be done with us yet!
&&
.AVIATION...
(00Z TAFS)
Issued at 514 PM CST Wed Mar 1 2023
Gusty winds will subside over the next hour or two and remain
light until around 18Z tomorrow. It will become very windy 18-00Z
causing major low level turbulence and crosswind issues at all TAF
sites. Models have been backing off on wind speeds at the northern
TAF sites so have kept them VFR with slightly lower wind speeds
and INK/FST/PEQ will drop to MVFR VIS in BLDU with periods
possibly to IFR.
Hennig
&&
.FIRE WEATHER...
Issued at 314 PM CST Wed Mar 1 2023
*Critical to Extreme Fire Weather Conditions Thursday*
Fire weather conditions are somewhat muted this afternoon as thick
high cloud cover continues to move across the area. This is limiting
the stronger winds from mixing to the surface. With that said, winds
are still gusting to near 30 mph across SE NM and the higher terrain
of W TX. Seeing a few breaks in the clouds, especially over the Big
Bend so stronger winds are still possible through the afternoon. No
changes will be made to the RFW currently in effect. Poor recovery
is expected overnight as any low level moisture remains to our east.
A very dynamic windstorm is still forecast to arrive Thursday
associated with an anomalys upper storm system. Ahead of a strong
Pacific front, a well defined LLTR will amplify from the Big Bend
north across the eastern Permian Basin. The front has slowed in
recent model runs so it appears the above area will experience
critical to extreme fire weather conditions for a longer period. A
strong mid level jet will mix to the surface behind the Pacific
front as it moves east across the region. Damaging winds are likely
which could cause new fire starts due to downed or arching power
lines similar to what we saw Sunday. On the bright side, if there is
one, cooler temperatures will limit RH`s to near 15% behind the
front. The fire environment doesn`t align great with the best fuels,
but given the extreme weather and a fire ongoing in the Davis
Mountains have upgraded the entire area to a Red Flag Warning.
Fire weather concerns decrease Friday into the weekend, but will
remain elevated due to very dry air in place.
&&
.PRELIMINARY POINT TEMPS/POPS...
Big Spring 47 74 36 68 / 0 10 10 0
Carlsbad 40 54 32 68 / 0 10 0 0
Dryden 57 82 42 73 / 10 0 0 0
Fort Stockton 52 71 38 69 / 0 0 0 0
Guadalupe Pass 35 45 30 57 / 0 30 0 0
Hobbs 40 58 30 65 / 0 10 10 0
Marfa 40 60 25 64 / 0 10 0 0
Midland Intl Airport 47 69 36 67 / 0 0 10 0
Odessa 48 68 36 67 / 0 0 10 0
Wink 43 64 34 69 / 0 0 0 0
&&
.MAF WATCHES/WARNINGS/ADVISORIES...
TX...Red Flag Warning until 9 PM CST /8 PM MST/ Thursday for Andrews-
Borden-Central Brewster County-Chinati Mountains-Chisos
Basin-Crane-Davis Mountains-Davis Mountains Foothills-
Dawson-Eastern Culberson County-Ector-Gaines-Glasscock-
Guadalupe Mountains Above 7000 Feet-Guadalupe and Delaware
Mountains-Howard-Loving-Lower Brewster County-Marfa Plateau-
Martin-Midland-Mitchell-Pecos-Presidio Valley-Reagan-Reeves
County Plains-Scurry-Terrell-Upton-Van Horn and Highway 54
Corridor-Ward-Winkler.
High Wind Warning until midnight CST /11 PM MST/ Thursday night
for Central Brewster County-Chinati Mountains-Chisos Basin-
Davis Mountains-Davis Mountains Foothills-Eastern Culberson
County-Guadalupe Mountains Above 7000 Feet-Guadalupe and
Delaware Mountains-Marfa Plateau.
Wind Advisory until 9 PM CST this evening for Andrews-Gaines-
Loving-Lower Brewster County-Pecos-Presidio Valley-Reeves
County Plains-Terrell-Van Horn and Highway 54 Corridor-Ward-
Winkler.
Wind Advisory from 9 AM to 9 PM CST Thursday for Borden-Dawson-
Gaines-Mitchell-Scurry.
High Wind Warning from 6 AM Thursday to midnight CST Thursday
night for Andrews-Crane-Ector-Glasscock-Howard-Loving-Lower
Brewster County-Martin-Midland-Pecos-Presidio Valley-Reagan-
Reeves County Plains-Terrell-Upton-Van Horn and Highway 54
Corridor-Ward-Winkler.
NM...Red Flag Warning until 8 PM MST Thursday for Chaves Plains-Eddy
Plains-Lea-Sacramento Foothills and Guadalupe Mountains.
High Wind Warning until 11 PM MST Thursday for Eddy County
Plains-Guadalupe Mountains of Eddy County.
Wind Advisory until 8 PM MST this evening for Central Lea County-
Northern Lea County-Southern Lea County.
Wind Advisory from 8 AM to 8 PM MST Thursday for Central Lea
County-Northern Lea County.
High Wind Warning from 5 AM to 11 PM MST Thursday for Southern
Lea County.
&&
$$
SHORT TERM...16
LONG TERM....29
AVIATION...10
Area Forecast Discussion
National Weather Service Melbourne FL
905 PM EST Wed Mar 1 2023
...New FIRE WEATHER, AVIATION, CLIMATE...
.DISCUSSION...
Mild West to SW winds will diminish at the surface overnight. More
recent guid has indicated a lower likelihood of extensive lower
clouds by daybreak. Additionally, fog should be less of a concern
as well given slightly higher winds than prev nights. Lows are on
track to reach the U50s to L60s by daybreak Thu. The current
forecast remains in good shape.
from prev disc...
Unseasonably warm and dry conditions will persist Thu with mostly
sunny to sunny skies and a SW wind flow 8-12 mph and a little
gusty at times. The sea breeze will develop in the afternoon but
it will be delayed, esp north of the Cape. Max temps in the upper
80s over the inland counties and interior coastal counties will
approach record highs, esp at LEE. Mid 80s along the coast.
Friday...Mid and low-level ridging drifts eastward into the
western Atlantic Friday, ahead of a low pushing through the
central US. This will lead to a tightening pressure gradient into
early afternoon, which will then relax into Friday night.
Southerly winds becoming southwesterly through the period,
increasing to up to around 20-25mph during the afternoon, with
higher gusts. Models continue to hint at a weak inverted trough
developing somewhere in east central Florida, which could limit
overall wind speeds at those locations. However, due to
uncertainty on where this trough would set up, or if it would
exist at all, have maintained higher wind speeds across the
forecast area. Also, areas that see the trough affect their wind
speeds will likely have a period of higher winds prior to its
development, anyway. No precipitation is expected, with near-
record highs once again in the upper 80s to lower 90s. Overnight
lows in the mid to upper 60s Friday night.
Dry, hot, and windy conditions will lead to very sensitive fire
weather conditions on Friday, and a Fire Weather Watch is in
place for Friday afternoon. A Wind Advisory may also be needed.
Saturday-Sunday (modified previous)...The low pressure moving
through the northern US will drag a cold front through the local
area this weekend, finally bringing an end to the daily pattern of
near record temperatures. Model agreement on arrival timing of the
front Saturday morning remains good, and continues to improve on the
front`s progression, with both the ECM and GFS stalling the front
across South Florida late Sunday, as high pressure builds in from
the north. Rainfall chances remain generally on the low side , with
the ECM proving a slightly rainier solution than the GFS, especially
to the north late Saturday night into early Sunday morning. Rain
chances Saturday remain largely unchanged at around 30-50 pct across
the northern half of the CWA, including a slight chance of
thunderstorms, though confidence on any storms forming is low due to
poor support. PoPs around 20pct on Sunday, mainly across the south,
as the front begins to stall.
Afternoon highs near record again Saturday ahead of the front, but
finally drop into the upper 70s to low 80s Sunday. Overnight lows
mostly in the low to mid 60s Saturday night (upper 50s in the far
north), drop into the mid to upper 50s for all but the Treasure and
Southern Space Coasts, who remain in the low to mid 60s.
&&
.MARINE...
Issued at 333 PM EST Wed Mar 1 2023
Tonight/Thu...Winds around 10 knots will veer SW overnight 10
knots near the coast and 15 knots well offshore. On Thu, W to SW
flow around 10 knots will turn SE near the coast in a 12-15 knots
sea breeze in the aftn. Seas 1-2 feet nearshore and 3 feet
offshore tonight and early Thu. Then 3 to 4 foot seas spreading to
the coast by Thu eve.
Friday-Monday...A tightening pressure gradient will lead to S to SW
winds around 20-25kts on Friday, especially over the offshore
waters. Winds then relaxing with the pressure gradient on Saturday
and veering northerly behind a weak cold front. By Sunday, high
pressure returns, with NE/E winds 10-15kts into early next week. The
wind direction will be favorable in keeping seas from building too
high, though they are expected to become 4-6ft with up to 7ft well
offshore into Friday night. Then, diminishing to 2-4ft by Saturday
afternoon. Showers and a storm or two possible Saturday into Sunday
over the waters, as the front drops through the area and stalls
across southern Florida.
&&
.FIRE WEATHER...
Issued at 817 PM EST Wed Mar 1 2023
Thursday...Lower min RH values expected falling near 30 percent
over the interior but holding 40-45 percent along the coast. SW
winds 8-12 mph gusting to 18 mph.
Friday-The Weekend...Critical fire weather conditions look likely
Friday due to gusty SW winds, min RH in the 30s to lower 40s, and
hot temperatures. These conditions will pose a significant fire
weather danger, regardless of whether RFW criteria for RH is
reached. Locally critical RH will be possible, especially in areas
that see the highest temperatures (mainly inland south of
Orlando). A Fire Weather Watch was posted for Friday afternoon
earlier this evening.
RHs recovery briefly to the L40s and above Sat with the cold
front passage, then decrease back to the M-U30s along and north of
I-4 Sun. Wrly 20ft winds 10-15 mph Sat become Nrly around 10 mph
Sun.
&&
.AVIATION...
(00Z TAFS)
Issued at 817 PM EST Wed Mar 1 2023
Recent runs of the HRRR and LAV alphanumerical guid prods has
been backtracking on likelihood of lower clouds cigs making it
significantly east in the forecast area. Initial development areas
depicted along the west coast overnight show some eastward
migration toward Osceola and Lake Co`s. Have depicted some LIFR by
daybreak at KLEE, but revised MCO to a non-broken deck of lower
stratus and some fog coverage aft 10Z. Becoming VFR areawide aft
02/14Z
&&
.CLIMATE...
Issued at 817 PM EST Wed Mar 1 2023
Near record high temperatures are forecast for the next
couple days.
Daily Record Highs through Friday, March 3rd:
Wed 3/1 Thu 3/2 Fri 3/3
DAB 87 (2023) equaled today 88 (1953) 88 (2001)
LEE 87 (2023) equaled today 86 (1971) 88 (2012)
SFB 88 (2021) 88 (2007) 90 (2012)
MCO 90 (1918) 90 (1918) 90 (2012)
MLB 89 (2021) 92 (2007) 90 (2001)
VRB 88 (2018) 91 (2007) 89 (2012)
FPR 89 (1913) 91 (2007) 90 (2012)
&&
.PRELIMINARY POINT TEMPS/POPS...
DAB 60 85 63 88 / 0 0 0 0
MCO 60 87 64 89 / 0 0 0 0
MLB 61 85 64 89 / 0 0 0 0
VRB 59 86 63 90 / 0 0 0 0
LEE 60 87 64 88 / 0 0 0 0
SFB 60 88 63 88 / 0 0 0 0
ORL 62 89 65 89 / 0 0 0 0
FPR 61 85 65 90 / 0 0 0 0
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...Fire Weather Watch from Friday afternoon through Friday evening
for FLZ041-044>046-053-058-141-144-154-159-164-247-254-259-
264-347-447-547-647-747.
AM...None.
&&
$$
SHORT TERM...Pendergrast
LONG TERM....Law
AVIATION...Pendergrast
Area Forecast Discussion
National Weather Service Morristown TN
920 PM EST Wed Mar 1 2023
...New UPDATE...
.UPDATE...
Issued at 910 PM EST Wed Mar 1 2023
Regional radar and satellite imagery show on-going widespread
showers and thunderstorms to our west ahead of a surface cold
front. Mesoscale analysis shows that a high shear/low CAPE
environment remains in place. Effective shear is generally around
40-60kts and 0-1km Bulk Shear ~25kts as a 30kt LLJ sweeps over the
region. Mesoanalysis also suggests that as the bulk of the
activity moves into East Tennessee(around 11pm to midnight) that
the 500J/kg CAPE line will begin to sink towards the TN/GA border.
So far, thoughts remain unchanged in regard to potential threats
tonight. The main being a few strong to severe storms with
damaging wind gusts. An isolated, brief tornado cannot be totally
ruled out in such a high shear environment either. Mid-level
lapse rates of 6C/km or less will mostly inhibit hail, with the
exception being development of any rotating updrafts. The
greatest chance for strong to severe storms will be in the
southern valley and along the Cumberland Plateau but the threat
does exist area wide.
Additionally, periods of moderate to heavy rainfall are likely
with favorable warm rain processes. As it stands, the 700-300mb
mean flow is not quite parallel to the surface boundary
orientation but close enough that a few training areas of higher
rain rates cannot be ruled out. This is seen in both the 23Z and
00Z HRRR runs where it suggest an axis of accumulation totals in
excess of 2 inches is possible in the vicinity of the I-40
corridor. 00Z NAM shows something similar but maxing out around 2
inches. With 3 hour FFGs in this region around 1.75 to 2.5
inches, some flooding concerns could arise.
&&
.SHORT TERM...
(This evening through Thursday)
Issued at 248 PM EST Wed Mar 1 2023
Key Messages:
1. An area of moderate to heavy rains will move across the area
late tonight and early Thursday morning. Heaviest rain will be
south of interstate 40 where localized flash flooding is possible.
2. Isolated severe storms are possible across the southern Plateau
and southeast Tennessee late tonight and early Thursday morning.
Main concern will be damaging winds and possibility an isolated
tornado.
Discussion:
Currently, breezy southerly winds are already pulling moisture
back into the Tennessee valley with dewpoints increasing into the
lower 60s over southeast Tennessee. A frontal boundary was moving
southeast over the IL. This boundary will move into the Tennessee
valley overnight and Thursday morning.
For Tonight, this frontal boundary will continue to move southly
southeast across the Tennessee valley. A strong upper level jet
will move across the Ohio and Tennessee valley producing large
scale ascent over the region and strengthening the frontal-genetic
forcing along this front. Widespread showers and thunderstorms
can be expect with this forcing with the main time-frame between
11 pm to 5 am EST.
NAEFS tables show both 850mb moisture transport and PWs anomaly
high so do expect some moderate to heavy rainfall at times with
the greatest threat along and south of interstate 40. Would be
more concerned for the potential of flash flooding if the HREF
CAMS were showing training of storms but currently the convection
will be propressive in nature. However, due to heavy rains and
expected high rainfall rates due to the warm-rain process, do
expect localized flash flooding.
Besides the heavy rain, there is also a severe weather threat
across the southern Plateau and southeast Tennessee. HRRR and HREF
shows an environment with high shear, low CAPE and saturated.
Enough 0-3km CAPE (around 40-70) to produce decent updraft. Only
concern is will the updraft be surface based -vs- elevated. Main
threat will be isolated damaging winds and potential of isolated
tornado.
The upper dynamics will move east of the area during the morning
with a brief period of drier conditions until isentropic lift
increased by late afternoon and evening with a return of showers
and thunderstorms.
&&
.LONG TERM...
(Thursday night through next Wednesday)
Issued at 248 PM EST Wed Mar 1 2023
Key Messages:
1. Growing concern for the potential of widespread damaging wind
gusts to impact the area on Friday ahead of the line of showers and
storms. 40 to 50 mph gusts are probable across all valley locations,
with some gusts reaching between 50 and 60 mph. Wind gusts from 70
to 80 mph will be probable across our higher elevations of the east
TN mountains and foothills. If these winds materialize, numerous
downed trees and power outages are possible due to the strength of
the winds combined with saturated soils from recent rainfall.
2. A line of showers and thunderstorms will move across the area
Friday afternoon. Some of these storms could be strong to severe
with damaging straight line winds the main threat, and an isolated
tornado possible.
General Overview of Thursday night into Friday:
We start the period with a warm frontal boundary draped across our
area in a west/east orientation. Showers and a few storms will be
ongoing across the area. The front will lift north of our area
through the night into Friday morning and precip chances will
decrease as we enter the warm sector behind the front.
On Friday, a deep area of low pressure is set to move from the
Missouri River Valley up into the Ohio River Valley. A few showers
may be around through the day but then a line of showers and storms
will move into the area Friday afternoon/evening from the west, some
of which could be strong to severe. An anomalously strong windfield
will be present with this system and is cause for concern in
relation to both the severe threat and winds ahead of and long the
cold front. More below...
Severe Threat:
As is the norm with our winter/early spring events, how much
available CAPE is the big question with this system. As of now, both
GEFS and ECMWF means are showing a 10 to 20% chance of reaching 500
J/kg CAPE. This bears watching closely because shear values are very
impressive due to an anomalously strong wind field throughout the
profile. Current NAEFS table mean wind speeds and climatological
percentiles show max values for wind speeds at 700 and 500mb, with
850mb being in the 90th percentile range as well. Having said that,
the main threat *as of now* will be straight line damaging winds as
these higher winds aloft could be mixed down to the surface, with a
slight risk of an isolated tornado. Due to the impressive wind
speeds aloft, wind gusts in excess of 70 mph are possible if storms
can tap into these higher winds and bring them down to the surface.
If we can get a decent amount of instability to develop, the risk of
an isolated tornado increases.
Gradient Winds/Mountain Waves:
As noted above in the Severe Threat section, wind fields aloft will
be near or at max climatological values on Friday. A very strong
850mb jet of around 70 kts will be overhead. Down closer to the
surface, both the deterministic GFS and NAM show 925mb (about 2000
feet MSL) wind speeds around 40 kts. Damaging wind gusts across our
high terrain areas are almost a certainty due to these impressive
winds with gusts from 70 to 80 mph. We will also have to monitor the
potential for localized stronger winds due to mountain wave
enhancement due to a favorable wind/terrain orientation. Down in the
valley/rest of our area, significant wind gusts are also possible
for the aforementioned reasons with gusts from 40 to 50 mph probable
areawide, with some areas seeing gusts from 50 to 60 mph. Some type
of wind product will be needed on the following shift.
Things quiet down behind the cold front, leading to cooler and quiet
weather over the weekend and into next week. Temperatures are
expected to be near seasonal normals with the next chance for rain
coming around Tuesday.
&&
.AVIATION...
(00Z TAFS)
Issued at 641 PM EST Wed Mar 1 2023
Increasing coverage of showers and thunderstorms overnight will
result in poor flight conditions until early Thursday. Showers and
storms will gradually decrease Thursday morning but model derived
soundings suggest MVFR cigs could persist into mid-day. Winds
will generally be light at around 10kts or less but some higher
gusts could be possible with any locally stronger shower/tstorm.
&&
.PRELIMINARY POINT TEMPS/POPS...
Chattanooga Airport, TN 61 70 60 72 / 100 80 80 60
Knoxville McGhee Tyson Airport, TN 59 68 57 72 / 100 30 80 90
Oak Ridge, TN 58 68 56 72 / 100 30 80 90
Tri Cities Airport, TN 56 66 54 68 / 100 40 90 90
&&
.MRX WATCHES/WARNINGS/ADVISORIES...
NC...NONE.
TN...NONE.
VA...NONE.
&&
$$
SHORT TERM...DH
LONG TERM....SR
AVIATION...KRS
Area Forecast Discussion
National Weather Service Raleigh NC
940 PM EST Wed Mar 1 2023
.SYNOPSIS...
A weak front stretching across western and southern North Carolina
will lift slowly northward through North Carolina as a warm front
late tonight. A weak cold front will follow, shifting eastward
through the area Thursday morning before stalling over the Carolinas
and holding in place through Friday. A strong low pressure system
crossing the Ohio Valley and Great Lakes regions will drag a cold
front through the area late Friday night.
&&
.NEAR TERM /THROUGH TONIGHT/...
As of 940 PM Wednesday...
...Strong storms possible in the NW Piedmont later tonight...
The primary weather focus this evening for us is the areal expansion
of the marginal (level 1 of 5) risk of severe storms by SPC into our
NW Piedmont for later tonight, mainly a hail threat. The latest
surface analysis shows the weak frontal zone / edge of stable pool
extending from far NE NC along the S edge of the CWA and central
Foothills into far NW NC. The front then continues to a prominent
low over OH, with a trailing cold front along the IN/KY border and
through the MO Bootheel to AR/TX. A prefrontal trough is evident in
the warm sector from N LA across N MS into central TN. Between these
two latter features, widespread strong to severe convection persists
from AR and N MS/AL into central/E TN/KY. The mid level flow over
the Mid South/Carolinas remains fairly flat with a gentle
anticyclonic curve (marred only by an MCV which models depict
crossing VA/NC with the convection late tonight/Thu morning). We`ve
briefly lost much of the afternoon cloud cover which has shifted E,
however the preconvection cloud shield is already rushing into W NC.
The main challenge tonight is determining what will happen to the
ongoing convection as it shifts eastward into the Mid Atlantic
region overnight. The dynamic forcing for ascent will remain
somewhat muted, with only the MCV evident through the mid levels,
and the vigorous jet-induced upper divergence currently to our W
over TN into N MS/AL is expected to weaken as it heads eastward
overnight. The thermodynamic environment to our W and WSW supporting
the ongoing storms is decent, with moderate CAPE and fairly steep
mid level lapse rates noted on 00z soundings at JAN/BMX/FFC and
recent ACARS soundings near BHM. But the better (6+ C/km) MLLRs will
remain suppressed just S of NC and push entirely to our S overnight.
The 925-700 mb LRs are nearly 6.5 C/km over central NC currently but
are projected to shift to our E overnight. Beneath this layer, the
surface-based stable pool is expected to linger well into tonight
but weaken as it`s overtaken by increasing SSW flow (although
confidence in a nocturnal mix-out of a stable pool over the Piedmont
is usually fair to low, and I wouldn`t be surprised if the models
are wrong and the weak stable pool holds through daybreak). Chasing
the better thermodynamic environment will be the strengthening wind
field, including the arrival of a 70-80 kt mid level jet across
NC/SC very late tonight concurrent with a 40-50 kt SW 850 mb jet
nosing into the NC Piedmont. While the features don`t line up
temporally (the already-low CAPE exiting as the wind field
strengthens and hodograph lengthens and straightens), given this
robust deep layer shear, there is enough potential for a strong
storm to survive the mountains (and overall nocturnal stabilization)
for a risk of storms late tonight into Thu morning, mainly across
the N two-thirds of the CWA, according to CAM consensus including
HREF paintballs. I don`t have a lot of confidence that we`ll see
hail tonight, much less severe hail, given RAP projections with
little to no CAPE overnight along with the lack of ground truth
reports from upstream in the last few hours. Nevertheless, the risk
is non-zero, and have updated the Hazardous Weather Outlook to
include this risk. Otherwise, with minor temporal and spatial
adjustments, have retained the W-to-E trend of pops toward high-
chance (far S) to categorical (N) through the rest of the night and
into Thu morning, with an hour or two potential for isolated thunder
added in most areas. Temps are expected to move little tonight, and
perhaps rise a few degrees, with the incoming blanketing clouds and
higher dewpoints advecting in. Temps for the rest of the night will
range from the upper 40s to around 50 N to the lower 60s S. -GIH
Earlier discussion from 230 PM: Water vapor satellite showed a broad
ridge across the Caribbean providing nearly zonal flow across
central NC, an upper low lifting northeast across the Midwest and a
deep upper low across southern CA. Surface observations displayed a
warm front stretching from the southern Piedmont to the central
Coastal Plain. The warm front will continue to lift north across the
region this afternoon. This evening will be dry, then a prefrontal
trough and shortwave aloft will develop an area of showers and
isolated thunderstorms from west to east across the region tonight.
Conditions should be stable enough to prevent storms from becoming
strong, however lightning is expected as they traverse the region.
Temperatures will drop to the low-50s N to mid-60s S by late
evening, then become fairly steady the rest of the night as cloud
cover thickens and precipitation develops. Rainfall amounts will
range from just over one-half inch for the northern half of central
NC to near two-tenths near the SC border.
&&
.SHORT TERM /THURSDAY AND THURSDAY NIGHT/...
As of 300 PM Wednesday...
Broad upper ridging will remain anchored across the Caribbean
Thursday, and with a deep upper low digging across the Desert
Southwest. A strong upper jet will develop between these features,
creating several rounds of precipitation that will round the ridge
and move from TX the Carolinas starting Thursday. At the surface, a
prefrontal trough will move southeast away from the region in the
morning, then a cold front will sag southeast across the area in the
evening. Showers will linger near the NC/SC border throughout the
day as the trough slowly stalls, with areas near and north of the
Triangle having a temporary break in the rain in the afternoon.
Showers will then redevelop in the evening as the next cold front
moves towards the region, with coverage expanding across all areas
overnight as isentropic ascent develop. Rainfall amounts through the
period will generally be less than one-half of an inch. Highs: 70s.
Lows: mid-40s N to low 60s S.
&&
.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
As of 135 PM Wednesday...
Friday will be the most impactful portion of the forecast through
Wednesday, bringing a chance for severe weather, mainly across the
western Piedmont with a decreasing threat with eastward extent.
A closed low over the ArkLaTex region Friday morning will lift
northeast into the OH Valley and Lower Great Lakes region by 00z
Saturday, transitioning into an open wave by 12z Saturday over the
Northeast. At the surface, a strong surface low pressure system over
the Lower MS Valley will quickly move into the OH Valley by 7PM
Friday. Strong, warm southerly flow will pull a remnant boundary to
our south through the area by late Friday evening. There is still
fairly considerable timing differences in regard to the northward
progression of the boundary as a warm front. This boundary will be
the greatest forecast concern as along and south of this boundary
will be the primary focus for severe weather. Latest 12z guidance
shows the front anywhere from the NC/SC border (12z NAM), bisecting
central NC (CMC/Euro), or north of the NC/VA border by 00z. The
afternoon update focused more heavily on the middle-of-the-road
solution that the Canadian and Euro are suggesting, given stratiform
rain across the northern tier of counties earlier in the day may
slow the northward progression Friday afternoon/evening. Before the
convective line approaches the area, locations south of the warm
front will likely experience strong southerly winds 15-25 mph with
gusts 30-40 mph and temperatures soaring into the upper 70s to
low/mid 80s; while areas north of the front will see 10-15mph winds
and highs in the upper 50s to low 60s.
Convective evolution is still fairly uncertain as timing of
convection will become increasingly unfavorable within the diurnal
cycle and drier air aloft nipping at the heels of the convective
line. Additionally, deep layer forcing for ascent will be well to
the north of central NC as the closed low progresses into the Great
Lakes Region. However, there is enough evidence with surface based
CAPE 200-700 J/kg co-located with impressive 0-6km shear of 70-85kts
and 0-1km shear of 35-45kts, to mention the threat for damaging
straight line winds with the convective line and embedded tornadoes,
especially west of the Raleigh area. Dry air in the mid-upper levels
is expected to overspread the area after 06z and limit the deeper
convection with mainly showers as the front moves through the
remainder of the area.
Behind the front, surface high pressure builds in through Monday
afternoon bringing drier conditions and only slightly above normal
temperatures. Return flow around the high as it shifts offshore
Monday night will raise temperatures 10-15 degrees above normal
before another cold front brings cooler, drier air back into central
NC through Wednesday
&&
.AVIATION /00z THURSDAY THROUGH MONDAY/...
As of 615 PM Wednesday...
TAF period: While the TAF period will start with calm conditions or
light wind out of the south, an area of rain will move in from west
to east after midnight and last through mid-morning. MVFR conditions
are expected at most terminals, although the lower clouds appear
likely to remain north of FAY and a brief period of IFR ceilings
cannot be ruled out at RWI. Confidence in a thunderstorm occurring
late tonight around sunrise is low, but decided to keep it mentioned
in the TAF since its removal might be interpreted as no chance of a
thunderstorm. Conditions will improve by late morning, both with a
return to VFR conditions and rain moving to the east. In addition,
some marginal LLWS still remains possible near FAY, but should not
be a threat at other sites.
Outlook: A few cold fronts approaching the region will increase
precipitation and storm chances Thursday night into Friday, with
associated sub-VFR conditions. Strong SW winds with frequent gusts
of 30 to 40 kts are also expected Friday ahead of the cold front.
VFR conditions will return Friday night and should remain
predominately VFR through the weekend into early next week.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SYNOPSIS...Hartfield
NEAR TERM...Hartfield/JJT
SHORT TERM...JJT
LONG TERM...Swiggett
AVIATION...Green/JJT
Area Forecast Discussion
National Weather Service San Diego CA
200 PM PST Wed Mar 1 2023
.SYNOPSIS...
The cold Pacific storm will continue to bring showers with a few
thunderstorms to the region this afternoon, with locally heavy rain
and snow rates. Strong west winds will continue through this
evening. Precipitation will end this evening with clearing skies and
diminishing winds late which will result in a cold night tonight and
widespread frost in the valleys and even some coastal areas.
Dry weather will prevail with gradually warmer days Thursday through
Saturday. Low pressure to the north will bring slight cooling to the
region with stronger west winds in the mountains and deserts early
next week, with a small chance of precipitation.
&&
.DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE...
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
Showers with locally heavy rain rates, hail and isolated lightning
strikes are continuing this afternoon as the upper low continues to
move southeast across the Mojave Desert. Snow levels continue to
fall as colder air moves in and is mostly in the 2000-3000 foot
range. Numerous wind gusts over 50 MPH hvae been reported today with
local gusts around 70 MPH. Latest HRRR shows precip gradually
diminishing late this afternoon and this evening, and due to
developing north flow it should linger in the San Bernardino
Mountains as late as around midnight, so the winter storm warning
has been expanded until midnight there.
Skies should clear overnight, and the winds should mostly become
light by midnight as the switch to northerly winds will mostly just
occur in the San Bernardino County Mountains. With the cold air
mass, we will have some lows in the mid to upper 20s in coldest
valleys with a lot of lower 30s, but the wet ground will moderate
this slightly (if this were a dry system, we would be even colder).
There will be a lot of visible frost in this case, and near the
coast there will be a lot of 30s. We will need to issue freeze
warnings for the valleys tonight and frost advisories in most
coastal areas.
The upper low will finally move east Thursday and bring dry weather
through at least Saturday. Temperatures will gradually increase,
both day and night, but remain below seasonal levels. At least we
should have quite a few 60s west of the mountains by Friday instead
of just 50s. EPS ensemble is showing more than 50% of members
showing at least light rainfall around late Sunday or Monday next
week with GEFS members somewhat drier. Precipitable water amounts
mostly remain below 1/2" but enough saturation below 800 MB could
result in some light precip given the troughing to our north. The
cluster analysis has about half the solutions indicating a West
Coast ridge and half the solutions indicating continued troughing
(especially GEFS contributions) for the second half of next week,
meaning confidence is low for any forecast then with general
predictability ending around Tue/Wed next week.
&&
.AVIATION...
011630Z...Clouds with variable bases 1500-4000 feet MSL with
additional layers up to 10000 feet. RA and mountain SN through 20Z
with mountain slopes mostly obscured. RA/SHRA tapering off from
northwest to southeast after 20Z, ending by 05Z. CIGS locally
lowering to 1200-2500 feet MSL with vis 2-4SM during showers.
Isolated CIGS down to 800 feet with vis 1SM in heavier SHRA. Rapid
clearing north to south overnight.
Southwest to west winds gusting 25-35 kt at the coast and valleys,
and 30-45 kt in the mountains and deserts with isolated gusts to 60
kt on the desert slopes. STG-SVR up/downdrafts, LLWS, and rotors
likely over and NE/E of the mountains. Rotors likely VCTY KPSP at
times. Winds weakening for the coastal areas and valleys this
evening.
&&
.MARINE...
Hazardous winds and seas through most of tonight. West winds are
expected to gust 35 to 40 kt with combined seas of 10 to 14 feet.
Strongest winds are expected through 10 PM, then weakening Thursday
morning. Check the Gale Warning for more details. Conditions will
improve rapidly Thursday morning and no additional marine hazards
are expected through Sunday.
&&
.SKYWARN...
Skywarn activation is not requested. However weather spotters are
encouraged to report significant weather conditions.
&&
.SGX WATCHES/WARNINGS/ADVISORIES...
CA...Wind Advisory until 6 PM PST this evening for Orange County
Coastal Areas-Orange County Inland Areas-San Bernardino and
Riverside County Valleys-The Inland Empire-San Diego County
Coastal Areas-San Diego County Valleys.
Frost Advisory from midnight tonight to 8 AM PST Thursday for
Orange County Coastal Areas-Orange County Inland Areas-San
Diego County Coastal Areas.
Winter Weather Advisory until 6 PM PST this evening for San
Bernardino and Riverside County Valleys-The Inland Empire-
Santa Ana Mountains and Foothills.
Freeze Warning from midnight tonight to 8 AM PST Thursday for
San Bernardino and Riverside County Valleys-The Inland
Empire-San Diego County Valleys.
Winter Weather Advisory until 8 PM PST this evening for San
Diego County Valleys.
Winter Storm Warning until midnight PST tonight for San
Bernardino County Mountains.
Winter Storm Warning until 10 PM PST this evening for Riverside
County Mountains-San Diego County Mountains.
Winter Weather Advisory until 4 PM PST this afternoon for Apple
and Lucerne Valleys.
High Wind Warning until 10 PM PST this evening for Coachella
Valley-San Diego County Deserts-San Gorgonio Pass Near
Banning.
PZ...Gale Warning until 4 AM PST Thursday for Coastal Waters from San
Mateo Point to the Mexican Border and out to 30 nm-Waters
from San Mateo Point to the Mexican Border Extending 30 to
60 nm out including San Clemente Island.
&&
$$
PUBLIC...Maxwell
AVIATION/MARINE...PG