Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 03/22/23
Area Forecast Discussion
National Weather Service Charleston SC
1012 PM EDT Tue Mar 21 2023
.SYNOPSIS...
High pressure will remain the primary feature across the region
through the rest of the week. A cold front is expected to pass
through on Saturday, followed by unsettled conditions early
next week.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
The lower levels of the atmosphere are starting to moisten as
evidenced by the 00Z soundings from KJAX and KCHS, and the
Satellite Layer Blended Percent of Normal imagery. KJAX PWat is
0.91 inches (close to normal) while KCHS PWat is 0.47 inches
(around 35% of normal). Dew points are gradually climbing
through the 40s in most places, and dew point depressions are
shrinking. The increase in moisture and the isentropic ascent
will continue to produce a further development of stratocumulus
from the south and southeast, along with cirrus clouds coming in
from the west.
Recent temp trends support lowering temps even more across many
parts of the Charleston quad-county region, where radiational
cooling will persist longer. We now have min temps as cold as
near 40 degrees in the Francis Marion National Forest to the
lower and middle 50s along the barrier islands. Cloud cover will
put a damper on the hourly decline, and temps look to hold
steady or even rise, most notably northern sections where sky
cover will transition from clear to mostly cloudy/cloudy.
Previous discussion...
High pressure will pull further into the ocean off the mid-
Atlantic region within the zonal flow aloft. During this
transition an inverted trough becomes better defined off our
coast. This feature doesn`t move too much toward shore through
the night, but it does allow for onshore moisture advection to
combine with increasing isentropic ascent on the 290K and 295K
surfaces to cause increasing stratocumulus from south-southeast
to north-northwest. Condensation pressure deficits seem a bit
too high for any showers over land, but we do show "silent" 10%
PoPs over coastal Georgia late. The increase in cloud cover and
warm advection will allow for a much warmer night when compared
to the past two nights. But temps will still be a challenge, as
there will be decent radiational cooling early on, especially
north and northwest until the cloud cover increases. This allows
us to lower some temps, most notably in the Francis Marion,
which will take the longest for skies to become mostly cloudy.
Once the cloud cover expands, temps will generally hold steady
the rest of the night.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH FRIDAY/...
Wednesday and Wednesday night: Aloft, zonal flow will prevail ahead
of an advancing and building ridge centered across the Gulf of
Mexico. At the surface, the day will begin with high pressure
centered just off the Mid Atlantic coast and a coastal trough
paralleling the Southeast coast. As the high shifts a bit further
east, the coastal trough is expected to draw closer to shore and
even push onshore during the afternoon. For the past several cycles,
several model solutions have been depicting showers breaking out
across the forecast area and the adjacent coastal waters. These
showers will be forced by convergence within the coastal trough and
the presence of a well defined thetaE ridge that is poised to extend
inland into the forecast area. Solutions such as the HRRR and the
HREF mostly isolated and light, and this makes sense given the
presence of impressive precipitable water values (1.2-1.3 inches)
but the lack of any significant large scale forcing for ascent. All
of this to say, we have introduced a 20 percent chance of showers
across much of the forecast area that roughly spans from the mid
morning hours through the late afternoon. Shower activity should
come to an end quickly through the evening and the rest of the
overnight is expected to be dry. Temperatures are expected expected
to warm considerably from previous days, though exact values will be
tricky given the presence of cloud cover. Where more cloud cover is
expected, highs should top out in the low to mid 70s which is
basically from along the Savannah River eastward. Areas further to
the west, and especially along and south of I-16, highs could reach
the upper 70s.
Thursday through Friday: Upper ridging will build across the region
Thursday and persist through Friday. At the surface, high pressure
over the Atlantic will extend westward into the forecast area
providing a nice setup for warming conditions. The main forecast
issue for the end of the week will be temperatures. Look for low to
mid 80s on Thursday with mid to upper 80s being more common on
Friday. The immediate coastline will be several degrees cooler each
day thanks to what should be a progressive sea breeze each
afternoon. Expect breezy conditions each afternoon overall, with the
strongest winds expected Friday.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
The long term period will begin with a cold front quickly
approaching the forecast area from the west Friday night and
crossing the area on Saturday. The timing of this front has shown
some run to run variable, with the overall trend showing a slightly
later passage. The later this front arrives, the more time there
will be for destabilization and the chances of thunderstorms will
increase. Therefore, we have added in a slight chance of
thunderstorms for Saturday. Also of note, model soundings show a
nice increase in mid-level flow which would yield deep layer shear
on the order of 50 knots. So, though there are lots of details to
still iron out, we can`t completely rule out a low end severe
threat. The front will move offshore Saturday night and then Sunday
should be a relatively quiet day. As we move into early next week,
model guidance now shows a front lifting into the area and producing
unsettled conditions. Overall forecast confidence is quite low at
the end of the forecast period.
&&
.AVIATION /02Z WEDNESDAY THROUGH SUNDAY/...
Cloud cover will increase and eventually lower and thicken as a
coastal trough offshore draws closer to the terminals. We have
VFR at all sites tonight into the middle of Wednesday afternoon,
followed by MVFR ceilings, especially at KCHS and KJZI. All
sites have some chance of showers after 15Z Wednesday, and for
now we have VCSH until radar trends become better defined.
Extended Aviation Outlook: Brief MVFR conditions and light rain
showers could impact the terminals Wednesday evening.
Otherwise, VFR conditions should prevail. Breezy conditions are
expected Thursday afternoon, and especially Friday into
Saturday. In addition, can`t rule out a thunderstorm as a cold
front crosses on Saturday.
&&
.MARINE...
Overnight: A 1032 mb high offshore the Delmarva will pull east,
while an inverted trough sharpens across the immediate coastal
waters. Typically this feature has a difficult time penetrating
the cooler shelf waters, which will result in E and NE winds
around 15 or 20 kt. There will be some gusts around 25 kt on the
Georgia waters early on, but they look to be infrequent. The
favorable onshore fetch will yield elevated seas as high as 4 or
5 feet within 20 nm and up to 6 feet further out, and we have a
Small Craft Advisory on the Georgia waters 20-60 nm out.
Wednesday through Sunday: Relatively light east to northeast flow
will prevail Wednesday as a coastal trough lifts through the local
waters. Behind the trough, winds will turn southerly to
southwesterly Wednesday night and continue through Friday and into
the weekend. Wind speeds will begin to increase Thursday, and
especially Friday into Saturday as a cold front approaches from the
west. In fact, conditions will increasingly become supportive of
Small Craft Advisories Friday through Saturday for at least a
portion of the local waters. Conditions should then improve into
Sunday after the front moves through.
Rip Currents: The combination of onshore winds, some swell energy,
and favorable astronomical factors will continue to produce a
Moderate Risk of rip currents at all beaches Wednesday. An elevated
risk of rip currents is possible again on Thursday though overall
conditions will be less supportive than in days past.
&&
.TIDES/COASTAL FLOODING...
One more round of minor coastal flooding will be possible with
the Wednesday evening high tide around Charleston. The
astronomical high tide will actually be at its peak (6.22 ft
MLLW) Wednesday evening, and winds (though weaker) will still be
easterly or northeasterly. High tide will likely peak right
around the 7 ft MLLW threshold and a Coastal Flood Advisory
could be needed.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...None.
SC...None.
MARINE...Small Craft Advisory until 8 AM EDT Wednesday for AMZ374.
&&
$$
NEAR TERM...
SHORT TERM...BSH
LONG TERM...BSH
AVIATION...
MARINE...
TIDES/COASTAL FLOODING...
Area Forecast Discussion...UPDATED
National Weather Service Corpus Christi TX
805 PM CDT Tue Mar 21 2023
...New UPDATE Marine...
.UPDATE...
Issued at 758 PM CDT Tue Mar 21 2023
Winds have diminished along the coast and will cancel the SCA for
the near shore waters early. Winds are at SCEC levels over the
offshore buoys, but the seas are still elevated and winds should
pick up a little bit tonight as the low level jet increases to 30
knots. Sensors along the coast show vsbys have lowered to 2-3 nm.
Will issue a Marine Weather Statement to cover the lower
visibility in fog. With strong low level flow, not expecting the
fog to become dense, but there could be some patchy dense fog at
times during the overnight period.
&&
.SHORT TERM...
(Tonight through Wednesday night)
Issued at 342 PM CDT Tue Mar 21 2023
Key Messages:
- High rip current risk continues tonight, becoming moderate
Wednesday.
- Warming trend through Wednesday.
An upper level short wave that brought cloudy skies and
drizzle/light rain/patchy fog to South Texas, will exit to the
northeast of the area by early evening. The RAP and HRRR indicated
that light precipitation will continue across the Victoria
Crossroads through early evening. Thus, kept a slight chance through
01Z for the northeastern CWA.
Mid/upper level ridging will take place through tonight bringing
drier mid/upper levels across S TX. Given the drier airmass aloft
and continued low level moisture, fog will be possible tonight.
However, winds will remain elevated, keeping the fog light and
patchy. The upper level ridge will also lead to warmer temperatures
with less clouds/more sunshine for Wednesday.
Gusty southerly winds this afternoon, will decrease tonight, but
remain around 5 to 15 mph overnight. Southerly winds are expected to
strengthen Wednesday, especially across the Coastal Bend, in
response to a tightening pressure gradient across S TX as low
pressure deepens across W TX and northeastern Mexico.
The combination of long period swells and a new moon will maintain a
high risk of rip currents tonight. As winds become more southerly
across the gulf and swell periods decrease, so will the risk of rip
currents on Wednesday with the rip current risk expected to be
moderate.
&&
.LONG TERM...
(Thursday through next Monday)
Issued at 342 PM CDT Tue Mar 21 2023
Key Messages:
-Winds could reach advisory conditions over the Coastal Plains and
Coastal Bend Thursday ahead of the cold front
-Chance of showers and thunderstorms Friday morning into the early
afternoon hours
-Fire weather conditions could develop Thursday morning in the Rio
Grande Plains ahead of the front
High pressure will remain over the Gulf of Mexico Thursday while a
trough approaches the state from the west. This will allow the
pressure gradient to tighten and create windy conditions across the
area. Moderate to strong winds, RH values in the 30% range, and dry
fuels may lead to brief elevated fire weather conditions Thursday
morning into the early afternoon hours. Additionally, winds may
reach advisory levels across the Coastal Plains and Coastal Bend, so
will need to continue to monitor and issue a Wind Advisory in a
later forecast package should this trend continue.
The trough will travel eastward across the Plains and into the Great
Lakes region Friday through Saturday, and will eject a weak front
into South Texas during the day Friday. The front is not expected to
bring too much in the way of rainfall to South Texas, with highest
PoPs existing in the northern tier counties and into the Victoria
Crossroads (20-30% chance). There is a slight chance of
thunderstorms, though with SBCAPE on the lower side, expecting
storms to be elevated in nature.
Conditions will dry out in the wake of the front; however, onshore
flow will return Saturday afternoon with PWAT values quickly
rebounding to 1.5" by Sunday. A mid-level shortwave will allow for a
slight chance of showers on Sunday and Monday.
Another mid-level trough will move across the Rockies and into the
Plains early next week; however, models remain pretty varied on
timing and strength.
&&
.AVIATION...
(00Z TAFS)
Issued at 655 PM CDT Tue Mar 21 2023
Low stratus/IFR ceilings have persisted over the central coast
northwest toward BEA, while ceilings have lifted to low MVFR over
the Victoria Crossroads. Weak low level warm air advection, with
assistance from a weak mid level disturbance, will keep isolated
to scattered light showers/MVFR vsbys going through mid evening
from the northern Coastal Bend into the Victoria Crossroads. Low
level southerly flow will increase to 30-40 knots during the night
and spread westward into the Brush Country. Expect MVFR ceilings
will return to the eastern Brush Country by 03Z and into the
western Brush Country (LRD/COT) by 08Z Wednesday. IFR ceilings
will be prevalent over the coastal plains from 06Z-15Z with patchy
fog/MVFR vsbys possible. Improvement to VFR will occur from
17-19Z over the Brush Country as clouds scatter out, while
ceilings will lift to VFR over the coastal plains by mid afternoon
Wednesday. Gusty south-southeast winds are expected from 16Z
through the afternoon over the coastal plains with gusts over 30
knots at CRP in the afternoon.
&&
.MARINE...
Issued at 342 PM CDT Tue Mar 21 2023
Patchy light rain is expected to continue through early evening,
then slightly drier conditions filter into the area overnight with
the precipitation exiting to the northeast. Winds are expected to
decrease tonight with wind speeds dropping below advisory levels.
However, seas will remain around 7 feet across the offshore waters
through mid morning Wednesday. Therefore, have extended the Small
Craft Advisory for the offshore waters until 10 AM Wednesday. Moderate
to strong onshore flow and elevated seas will continue through
early Friday morning with periods of Small Craft Advisory
conditions possible through the week. Chance of showers and slight
chance of thunderstorms on Friday as a cold front approaches the
coast. Brief offshore flow may develop Friday night if the front
pushes into the waters with weak to moderate onshore flow
returning by Saturday afternoon. Another cold front may push
through the waters Monday into Tuesday.
&&
.PRELIMINARY POINT TEMPS/POPS...
Corpus Christi 68 81 69 83 / 0 0 0 0
Victoria 67 80 68 82 / 20 0 0 0
Laredo 70 90 71 95 / 0 0 0 0
Alice 66 84 67 91 / 0 0 0 0
Rockport 66 77 67 78 / 10 0 10 0
Cotulla 68 88 70 95 / 0 0 0 0
Kingsville 68 83 68 89 / 0 0 0 0
Navy Corpus 68 76 70 77 / 10 0 0 0
&&
.CRP WATCHES/WARNINGS/ADVISORIES...
TX...High Rip Current Risk until 7 AM CDT Wednesday for TXZ345-442-
443-447.
GM...Small Craft Advisory until 8 PM CDT this evening for GMZ231-232-
250-255.
Small Craft Advisory until 10 AM CDT Wednesday for GMZ270-275.
&&
$$
SHORT TERM...TE
LONG TERM....HA
AVIATION...TMT/89
Area Forecast Discussion
National Weather Service Dodge City KS
505 PM CDT Tue Mar 21 2023
...updated aviation section...
.SHORT TERM...(This evening through Wednesday night)
Issued at 357 PM CDT Tue Mar 21 2023
The mid afternoon water vapor loop and RAP analysis continued to
reveal a rather perturbed west-southwest flow pattern across much of
the CONUS. One embedded shortwave trough raced across Kansas earlier
today which was located near St. Louis, MO as of 20Z. A weak surface
low within the broader leeside trough pushed east into central
Kansas, but afternoon surface observations were showing this weak
surface low slowly dissipating as a new leeside low was developing
across southeast Colorado.
Tonight, the new southeast Colorado surface low will also push
quickly east across Kansas through Wednesday morning as another in
the series of low-amplitude shortwave troughs races across the
Central Plains. In addition to this, a shortwave trough across
Wyoming will move east tonight across the southern Dakotas, which
will push a polar front south across Nebraska, reaching north
central Kansas late tonight into early Wednesday morning. The
strength of this cold frontal push into Kansas early Wednesday
morning will be key to the remainder of the day forecast across our
northern counties -- particularly the I-70 corridor. The latest
forecast now calls for much of Trego and Ellis County remaining just
north of this polar front all the way through the afternoon and
early evening Wednesday...with areas of fog and low stratus through
the late morning hours.
The much more significant Southwest CONUS storm and associated
intense jet streak out ahead of it...will favor eastern Colorado for
the strongest low level response in terms of northward advancement
of the polar front as a warm front. In fact, the latest 18Z NAM
model that rolled in now has the front as far south as Jetmore at
21Z...keeping I-70 much cooler in the afternoon than our new going
forecast of around 70 for Wakeeney and Hays. There is big
temperature bust potential up along I-70 and even farther south
toward Scott City to Larned line.
Southwest of the front, the warm and windy forecast remains on
target. That said, we will keep the High Wind Watch going for the
western six counties (along/west of Highway 25), as 80% confidence
for warning criteria being met is not there with this latest
forecast update. The best forecast is peak wind gusts in the 50 to
55 mph range, but gusts up to 60 are still in question...at least
enough to not warrant an upgrade to a warning. We will keep the
"patchy" blowing dust going in the forecast for areas greater than
40 mph wind gusts and "areas" blowing dust for areas generally
greater than 50 mph wind gusts, which matches fairly well with WFO
AMA, PUB, and GLD (thanks for the collaboration).
The Wednesday storm will rapidly shear out across Colorado and lift
northeast across the Dakotas Wednesday night with trailing southwest
to northeast upper level jet remaining in place all the way down to
Baja Mexico where the next shortwave disturbance will be advancing
from (see the Long Term section for discussion on this system). A
lot going on...except for precipitation, unfortunately.
.LONG TERM...(Thursday through Tuesday)
Issued at 357 PM CDT Tue Mar 21 2023
As mentioned in the last paragraph of the Short Term section, a
trailing upper level jet streak will extend down into Baja in the
wake of Wednesday Night`s storm. This will result in only a modest
cold front passage with fairly weak winds poleward of the front, as
yet another surface low develops along the front. In fact, there may
be more than one sub-synoptic scale surface low along the front from
the Red River northwest up into the western Oklahoma Panhandle by
late Thursday afternoon. This setup will keep our southwest Kansas
region in the cooler airmass with northeasterly winds much of the
day. As the next shortwave trough within the larger scale southwest
flow pattern approaches Thursday Night, mid level frontogenesis will
increase in the 800-600mb layer across southwest Kansas. This will
favor at least light accumulating precipitation for our region. As a
result, 12-hr POPs have been bumped up to 40 percent or slightly
higher over a larger area of southwest Kansas for the Thursday Night
and also Friday periods.
The latest ECMWF deterministic model valid 18Z Friday shows a little
more concentration and favorable shape/positioning of the mid level
potential vorticity anomaly -- which would focus frontogenesis in
the 800-700mb layer squarely across southwest and west central
Kansas. All that said, the mid level wave will remain open, at least
at 500mb and will also be moving fairly quickly during the day
Friday, so while there is hope for widespread accumulating
precipitation, the quantity of precipitation will likely be in the
0.20 to 0.35 inch range for much of the forecast area. This is
suggested by the latest EPS means as the latest EPS 12Z run has a
pretty nice greater than quarter inch signal across much of
southwest and west central Kansas. The latest thermodynamic
soundings for late Thursday Night and Friday suggest a cold rain
event, although some wet snow cannot be ruled out before ending
and/or in small regions of stronger mesoscale upward vertical
motion.
The Thursday Night into Friday storm system will eject northeast
quickly and another one will be developing out across the southern
Rockies/Southwest late in the weekend. NBM POPs continue to increase
as confidence and model support increase (both deterministic and
ensemble). This late weekend storm system looks colder, so
probability of type being snow is better than the Thursday
Night/Friday system.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 502 PM CDT Tue Mar 21 2023
GOES16 Day Cloud Phase Distinction product is showing areas of
thin mid water cloud overspreading the west central and far south
west central Kansas counties – and none of this will impact local
terminals Tonight. Light and variable winds will continue to be
the rule as well before a frontal boundary slides south into the
area overnight, stalling probably south of Hays based on some of
the models. Additionally, some lower ceilings might occur based on
Hires Ensemble forecast for cigs < 1000 ft , but the
probabilities are not very high, (mainly in the 50-60 percent
range). And even at that, it’s likely to be limited in duration as
the warm front redevelops, spreading north early Wednesday.
Details on the ceilings levels at Hays will be tough to pinpoint
now and may still be a challenge to forecast Tonight.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 40 78 40 62 / 0 0 0 0
GCK 38 78 39 59 / 0 0 0 0
EHA 47 75 42 64 / 0 0 0 10
LBL 46 76 42 66 / 0 0 0 0
HYS 38 70 35 56 / 0 0 10 0
P28 47 82 48 66 / 0 0 0 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
Red Flag Warning from 1 PM CDT /noon MDT/ to 8 PM CDT /7 PM MDT/
Wednesday for KSZ043-061>063-074>076-084>086.
High Wind Watch from Wednesday afternoon through Wednesday
evening for KSZ061-062-074-075-084-085.
&&
$$
SHORT TERM...Umscheid
LONG TERM...Umscheid
AVIATION...99
Area Forecast Discussion
National Weather Service Lincoln IL
832 PM CDT Tue Mar 21 2023
.SYNOPSIS...
Issued at 832 PM CDT Tue Mar 21 2023
Breezy and damp conditions will prevail across central Illinois
tonight with temperatures remaining nearly steady in the upper 30s
and lower 40s. Warmer weather will arrive on Wednesday as highs
climb well into the 50s.
&&
.UPDATE...
Issued at 832 PM CDT Tue Mar 21 2023
A few light showers linger along/northeast of a Bloomington to
Mattoon line this evening as the short-wave trough responsible for
the rain pushes eastward into Indiana. Based on radar timing tools
and latest HRRR data, it appears the showers will end within the
next 1-2 hours...followed by cloudy and mostly dry conditions
through the night. A second short-wave trough further upstream
across the Plains will arrive by Wednesday morning, but its
associated showers will hold off until after sunrise. Low
temperatures tonight will drop just a degree or two from current
readings into the upper 30s and lower 40s. Thanks to continued
brisk S/SE winds gusting 15-20mph, wind-chill values will dip into
the 20s.
&&
.SHORT TERM...(This evening through Wednesday)
ISSUED AT 357 PM CDT Tue Mar 21 2023
An upper level shortwave will continue to produce rain especially
from near I-72 and southward this afternoon into evening, then
depart quickly to the east this evening. However, warm, moist
advection will continue behind this feature, and could continue to
bring scattered showers through the night, although with less
distinct lift and therefore lighter amounts likely.
Another shortwave looks to bring another more distinct region of
showers crossing the area sunrise to noon or so Wednesday,
tracking roughly along I-72, and have higher chance PoPs for that.
After that, a surface low will take shape in eastern CO and head
eastward, with the attendant warm front lifting into central IL.
Showers could continue through the day Wednesday, but thunderstorm
activity looks minimal during the afternoon with stronger
instability developing to the southwest behind the warm front.
Subtle warm advection at the surface, southerly winds, and cloud
cover look to bring mild temperatures overnight tonight, dipping
to near 40 at midnight and then subtly rising the remainder of the
night. Highs Wednesday should peak in the early evening behind
the warm front, reaching lower 60s in the south, but likely
remaining in the 50s for northern portions of the forecast area.
.LONG TERM...(Wednesday night through Tuesday)
ISSUED AT 357 PM CDT Tue Mar 21 2023
Main forecast concerns...
1. Thunderstorms, possibly severe, late Wednesday night
2. Heavy rainfall Thursday evening to Friday evening
3. Thunderstorms continuing into Thursday afternoon or evening
Late Wednesday night the surface low approaching from the west
arrives in west central IL, with several hundred J/kg elevated
CAPE possible, and could result in some strong thunderstorms
mainly with a potential for isolated hail north of I-72. Behind
the low, a cold front will sag southward through the area
Thursday, shifting precipitation chances southward through the
area and possibly stalling out in southeast IL Thursday night into
Friday as another low tracks out of the southwest along the front.
Heavy precipitation could result especially from I-70 southward,
where somewhere in the neighborhood of 3 inches could be common
for Thursday-Friday night totals. To the north, amounts should
taper off, being generally under an inch north of I-72. Severe
thunderstorm potential looks rather low Thursday but not out of
the question, with the front sagging through the area and limited
instability of a few hundred J/KG CAPE. Friday evening, a potent
low looks to finally arrive in southern IL. This will likely
provide some more severe thunderstorm potential and heavy rain,
but it is unclear how far north the track of this low will go.
A few additional disturbances could track through the area over
the weekend into early next week, but do not appear to be as
strong/wet as late this week.
Temperatures look to fluctuate near normal values in the Thursday
through early next week period, with no snow forecast.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 640 PM CDT Tue Mar 21 2023
An upper-level wave is currently triggering an area of light rain
across central Illinois...primarily along/east of a KPIA to KDEC
line. The rain will persist at the E/NE terminals for a couple
more hours followed by mostly dry conditions across the board for
the remainder of the night. MVFR ceilings will lower to IFR by
02z-03z, then remain IFR for the rest of the 00z TAF period. S/SE
winds will gust to around 20kt tonight, then gusts will increase
to 20-25kt east of I-55 by Wednesday afternoon.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...Barnes
SYNOPSIS...Barnes
SHORT TERM...37
LONG TERM...37
AVIATION...Barnes
Area Forecast Discussion
National Weather Service Lubbock TX
640 PM CDT Tue Mar 21 2023
...New AVIATION...
.SHORT TERM...
(This evening through Wednesday)
Issued at 309 PM CDT Tue Mar 21 2023
Early afternoon visible satellite imagery shows generally clear
skies overhead with high clouds to our southwest and west over New
Mexico. Temperatures at 2 PM are on track to hit forecasted highs in
the 70s over much of the area, with breezy southwesterly winds at 20-
25 mph gusting to 30 mph through sunset. High clouds to our west
will move over the area tonight, acting as a blanket and keeping low
temperatures in the upper 40s and 50s.
An upper low currently (2 PM) noted on upper-level water vapor and
RAP analysis entering the west coast will continue its trek east and
open into a trough. As this trough moves east, a lee cyclone over
eastern Colorado will strengthen, bringing breezy westerly winds for
tomorrow. Something that may help to tame winds some will be the
potential for high clouds over the area during the day on Wednesday.
These clouds may also knock temperatures down a few degrees compared
to what is currently forecasted in the 80s. Clouds or no clouds, we
will probably still climb to around 10 degrees above normal. These
dry, breezy, and warmer-than-normal conditions will bring increased
fire weather concerns and the potential for blowing dust tomorrow
afternoon. Thus, a Fire Weather Watch has been issued for much of
the area for tomorrow afternoon and early evening. More will be
discussed about fire weather concerns in the Fire wx section of
this discussion. GKendrick
&&
.LONG TERM...
(Wednesday night through next Monday)
Issued at 309 PM CDT Tue Mar 21 2023
By Thursday morning, troughing will be established to our west over
the Great Basin. Weak surface troughing will remain positioned
across the forecast area with a dryline bifurcating the forecast
area keeping surface moisture confined to the far southeastern
Texas Panhandle and portions of the Rolling Plains. This is where
some morning fog may be possible as Gulf of Mexico air continues
to advect into the region. As the trough approaches the forecast
area a surface low will emerge from southeastern Colorado and
bring a Pacific cold front through the forecast area. This will
bring some breezy westerly winds and drier air to locations on the
Caprock which may allow for elevated fire weather conditions.
East of this front, the northeast to southwest oriented dryline
should remain in place across the eastern portions of the forecast
area. Model guidance may be a bit aggressive with moving moisture
out of the forecast area therefore as the cold front overtakes
the dryline thunderstorm initiation is expected to occur within
our forecast area with storms then quickly moving to the east and
out of our area of responsibility. Depending on how quickly these
storms exit the forecast area a severe weather threat may be
possible across the eastern Rolling Plains but the greatest severe
weather threat will remain east of our forecast area.
Our upper-air pattern will remain nearly zonal through the remainder
of the forecast period which will keep our forecast area quiet.
Behind the front on Friday winds will be gusty out of the west
during the day but gradually diminish during the afternoon hours
as the core of the 700 mb jet moves east of the forecast area.
While high temperatures will be cooler on Friday (mainly in the
60s) very dry surface air will combine with the strong winds
leading to near-critical fire weather conditions area wide. Fire
weather will also be the main concern through the rest of the
weekend as the dry surface air remains in place although wind
speeds won`t be quite as strong but still breezy. Another cold
front is expected to drop south into the forecast area early next
week dropping temperatures a bit more but with dry air remaining
in place this will be a dry frontal passage. Fire weather concerns
may persist through the middle of next week as well as dry
surface air remains in place. /WI
&&
.AVIATION...
(00Z TAFS)
Issued at 640 PM CDT Tue Mar 21 2023
Continued VFR. Outside chance tonight for some LLWS at all the
terminals, although this remains marginal overall so will omit
mention from the TAFs. Else, gusty SW winds of 20-30 knots will
taper around sunset and then resume by late morning.
&&
.FIRE WEATHER...
Issued at 309 PM CDT Tue Mar 21 2023
A strengthening lee cyclone over eastern Colorado will bring breezy
downslope winds to the region, resulting in warming and drying of
the near-surface layer. This will allow for highs to be 10-15
degrees above normal, resulting in the potential of mixing up to 650
mb where 35+ kt winds will exist. Something that will help to reduce
mixing, and warming to a lesser extent, is an expected high cloud
layer over the region. However, there is disagreement in regard
to how dense high clouds will be, with global data having thicker
clouds than higher-res data. Nevertheless, warmer than normal
conditions, min RH 12-18%, and winds 20-30 mph, along with drying
fuel (ERCs exceeding the 70th percentile over the northern South
and Rolling Plains and southern TX Panhandle) will still bring
critical fire weather to much of the forecast area. Therefore a
Fire Weather Watch is in effect for tomorrow afternoon into the
early evening hours. GKendrick
A Pacific cold front will move east through the forecast area on
Thursday bringing breezy westerly winds to locations on the
Caprock as well as drier surface air. This may lead to a period of
elevated fire weather concerns across the western South Plains and
far southwestern Texas Panhandle during the afternoon and early
evening hours. More widespread critical fire weather conditions
will be possible Friday and persist through the weekend as very
dry surface air remains in place. Westerly winds will be strongest
on Friday with sustained winds around 30 mph leading to RFTI
values of 5-7 across a large portion of the forecast area. Wind
speeds will diminish some for Saturday and Sunday but with
sustained winds remaining around 20 mph RFTI values of 3-5 will
continue to be possible.
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
Fire Weather Watch from Wednesday afternoon through Wednesday
evening for TXZ021>037-039>042.
&&
$$
SHORT TERM...10
LONG TERM....58
AVIATION...93
Area Forecast Discussion
National Weather Service Nashville TN
753 PM CDT Tue Mar 21 2023
...New UPDATE...
.UPDATE...
Issued at 747 PM CDT Tue Mar 21 2023
Light rain is slowly spreading across Middle Tennessee this
evening. The 00Z sounding from OHX shows the results of
considerable moisture advection the past 12 hours, with PWAT
having jumped from 0.15" at 12Z to 0.70" now. The surface map
shows a warm from extending across the Tennessee Valley, with
existing showers all occurring north of the front. The latest
HRRR shows at least scattered showers lasting through the night
and tomorrow morning across Middle Tennessee, although QPF values
remain relatively low. No forecast changes are planned this
evening.
&&
.SHORT TERM...
(This afternoon through Thursday)
Issued at 145 PM CDT Tue Mar 21 2023
Not a half bad day across Middle TN, though clouds continue to pile
into the area ahead of our next weather maker. Radar across the mid-
state has had these light returns all morning and into the afternoon
hours. However with 30 deg dew point depressions across the area,
rain is finding difficult to reach the ground. This will change as
we move into the late afternoon hours. Heavier precip being shown
across West TN will finally make its presence felt in our
northwest counties over the few hours and this will spread across
the rest of the area this evening. Rains will last through mid-
afternoon tomorrow on the Plateau with expected rainfall totals
averaging around 0.5".
This current weather system will get completely out of here by
sunset tomorrow and without a frontal passage, along with a
strengthening upper ridge to our southeast, we are going to warm up
considerably on Thursday. Many spots will be pushing 80 degrees.
&&
.LONG TERM...
(Thursday through next Tuesday)
Issued at 145 PM CDT Tue Mar 21 2023
In any other forecast package, I`d be telling you that this Thursday
warmup would be setting the stage for a classic spring-time
severe weather threat. While a few strong storms and potentially
even some marginally severe storms will be possible Friday
evening, I`m still not completely sold on widespread severe
chances with this next system -- but I am seeing a couple of
things in forecast soundings that I`m paying more attention to.
First, there`s more dry air aloft ahead of what looks to be a line
of storms Friday evening. This could go towards intensifying
updrafts, which has not been shown in previous model runs. Lapse
rates are better than they have been, as well. CAPE is still not
impressive. A few hundred J/Kg is still the best I see, but with
the proximity of the surface low to Middle TN, we could get some
frontogenetical forcing to help overcome a lack of instability.
With that said, a line of thunderstorms is likely to move into the
area Friday evening and right now, I like areas west of I-65 (and
even better south of I-40) for a chance of strong to marginally
severe storms. Biggest concern will be damaging straight line
winds and maybe even some hail. Rainfall totals on the order of 1
to 2 inches will be possible, with higher amounts in our northwest
counties. If it so happens that these totals come with just the
line on Friday evening, some localized flooding will become
possible, as well. The catch with this is the inconsistencies of
QPF setup in the models during the day Friday. A couple models
have showers and maybe few storms up in the LBTL area Friday
afternoon, but many leave the entire mid-state dry due to
atmospheric capping ahead of the front. It`ll be close, but if we
can spread out the rainfall amount over 12 hours instead of 2-3
hours, flooding concerns should be pretty limited. What this does
mean is my PoP forecast consists of a pretty tight gradient across
the area on Friday. Coordination with HUN/MRX allowed me to
eliminate some of the stray WPC QPF across the south and east
during the 06-18Z time frame on Friday.
(Deep breath)
Storms should exit Middle TN Friday night and in their wake, we
don`t get a big cool down (break for celebratory cheers).
Temperatures should remain the 70s Saturday and Sunday, making for a
very nice weekend. Models have been decently in agreement with rain
chances returning Sunday night, but the evolution of this system is
still quite in disarray. For now, we`ll carry a decent chance for
just rain Sunday night into Monday morning.
&&
.AVIATION...
(00Z TAFS)
Issued at 643 PM CDT Tue Mar 21 2023
Showers will impact Middle Tennessee terminals overnight and
through Wednesday morning. Showers will slowly end from west to
east Wednesday afternoon. Cigs will decrease to MVFR Wednesday
morning with temporary reductions in visibilities with heavier
showers. MVFR cigs may improve to VFR at the end of the forecast
period, but will likely wait until after the taf period. Winds
will be southerly for the forecast period. Winds will increase to
around 10 kts by mid morning with some gusts to around 20 kts from
late morning through the afternoon.
&&
.PRELIMINARY POINT TEMPS/POPS...
Nashville 49 65 56 79 / 90 80 0 0
Clarksville 47 65 57 78 / 90 60 10 10
Crossville 42 57 49 74 / 90 90 10 0
Columbia 47 64 54 78 / 80 90 0 0
Cookeville 45 60 53 76 / 90 90 10 0
Jamestown 42 57 50 75 / 90 90 0 0
Lawrenceburg 47 62 54 78 / 80 90 10 0
Murfreesboro 47 62 54 79 / 80 90 0 0
Waverly 45 65 57 77 / 90 60 0 10
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
UPDATE.......Rose
SHORT TERM...Unger
LONG TERM....Unger
AVIATION.....Reagan
Area Forecast Discussion
National Weather Service Pocatello ID
119 PM MDT Tue Mar 21 2023
.SHORT TERM...Tonight through Wednesday night.
A warm frontal boundary will approach from the south and expect
snow to move south to north overnight tonight into Wednesday. A
winter weather advisory is in effect for the Bear River Range
where over 6 inches is expected through Wednesday night.
Elsewhere 3 to 6 inches is possible in mountains with locally
higher amounts far east at pass levels and 1 to 3 inches in Snake
Plain. Expect a change to rain in magic valley Wednesday afternoon
and a change or mixed precipitation American Falls to Pocatello.
Snow levels reach valley floors again late Wednesday. Temperatures
tonight will be near normal under cloud cover and remain well
below normal Wednesday with highs in the 30s and 40s.
GK
.LONG TERM...Thursday through next Tuesday. A cold upper level
trough remains anchored over the Western US through the period.
Weather is expected to remain cool and unsettled. Models swing a
series of shortwaves through the trough Friday and through the
weekend, but are rather inconsistent with the timing. The wave on
Friday appears the most consistent among deterministic models. The
06Z GFS/ECMWF ensembles are comparable with the shortwave, though
the GEFS is slightly faster in timing. Winds will still be gusty on
Friday and there may be some issues with blowing snow across the
Snake Plain and Eastern Magic Valley. The weekend will still be
dominated by a broad upper trough with fairly disorganized snow
showers. Some convective instability is noted in the models,
particularly in the afternoon, which may lead to some thunder or at
least some enhanced showers with some graupel. Another upper low is
seen in model forecasts early next week, leading to a continuation
of unsettled weather. Hinsberger
&&
.AVIATION...We sit between two systems today: a shortwave departing
to the east, and a second that will lift across NV today. Current
guidance shows improvements in ceilings this afternoon in wake of
the departing wave. The second wave will draw in some snow late
tonight, with best chances of onset as early as 06Z-07Z at PIH and
BYI, and around 10Z to 12Z at DIJ and SUN. While NBM MOS is favoring
MVFR conditions for the event, HRRR VIS guidance is indicating a
band of VIS < 1SM surging northward with the snow around 09Z to 13Z.
Interestingly, NBM MOS and HRRR are supporting fog development
around DIJ this evening. Hinsberger
&&
.PIH WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory from midnight tonight to 6 AM MDT
Thursday for IDZ060.
&&
$$