Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 04/15/21
Area Forecast Discussion
National Weather Service Gaylord MI
1132 PM EDT Wed Apr 14 2021
.UPDATE...
Issued at 1056 PM EDT Wed Apr 14 2021
Bands of light snow and rain continue to rotate south as upper
level low pinwheels across the region. Not much change at all
expected through the remainder of the overnight, with a mixture of
rain and snow expected. Expect some minor snow accumulations,
likely remaining at or under an inch across interior
areas...perhaps resulting in local slick travel as temperatures
fall to near freezing.
&&
.SHORT TERM...(Tonight through Thursday)
Issued at 435 PM EDT Wed Apr 14 2021
Water vapor imagery and RAP analysis show an interesting pattern
across the Lower 48 and vcnty. A trio of well-defined mid-level lows
are present, one over the western U.S., one centered over the
northern Great Lakes and one off of the Canadian Maritimes. The one
over the Great Lakes has supported nmrs -shra/-shsn across northern
Lower MI/eastern Upper MI today. While pcpn earlier was more
stratiform looking ahead of a shortwave moving around the southern
side of the mid-level low, pcpn now is taking on more of diurnal,
cellular look under limited daytime heating.
Mid-level low over the northern Great Lakes will drift se
tonight/Thu, reaching the Lower Great Lakes by Thu evening. Areas of
pcpn will continue to rotate around the low, affecting eastern Upper
and northern Lower MI. Up at around 850mb, warmer air noted n and ne
of the low over Quebec into adjacent northern Ontario will be pulled
w and s toward the fcst area tonight, resulting in a zone of
isentropic ascent as viewed on the 285-290k sfcs shifting s and w
across eastern Upper and northern Lower MI (nw half in particular)
tonight, then shifting e and se late tonight/Thu. This should yield
an increase in pcpn. In general, qpf from the various models lines
up quite well with the isentropic ascent. As boundary layer cools
tonight, expect ptype to transition to predominantly snow. Fcst
reflects snow accumulations up to around 1 inch over the Leelanau
Peninsula to around Kalkaska and down to around Cadillac tonight
with less than an inch Thu morning. However, with some of the models
generating qpf in the 0.2 to 0.3 inch range, certainly possible that
a few spots could see 2-3 inches of wet/sloppy snow. Expect the snow
accumulations to occur mainly on elevated or grassy surfaces.
Outside of the aforementioned area, snow accumulations will be less.
Ptype will transition back to rain during Thu. Expect min temps
tonight a degree or two either side of 32F
.LONG TERM...(Thursday night through Wednesday)
Issued at 435 PM EDT Wed Apr 14 2021
A persistent blocking pattern upstream of the Upper Great Lakes will
bring near- to below-normal temperatures through the long term
period with minimal pcpn chances until a fropa Monday into
Tuesday. Models suggest that a pseudo Omega Block at the end of
this week off the West Coast will transition into a Rex Block
pattern across the Pacific by the start of next week.
While this blocking pattern has held a cutoff low over much of the
Upper Great Lakes region through the start of this week, this system
is expected to drift east of the area by Friday, as light northerly
flow remains across Northern Michigan. As this low exits, Northern
Michigan is left in a bit of the doldrums as upper-level flow is
light and the gradient remains ill-defined. This pattern will
continue through the weekend, with little to no precipitation
expected and temperatures running near to slightly below normal in
the low to mid 50s. By Monday morning, the Omega Block ridging is
expected to weaken as downstream troffing is expected to develop,
bringing a clipper shortwave and assoc cold front across the area
Monday evening/night. While the GFS is a bit more aggressive and
spins of an area of low pressure over Lake Superior, EC/GEM ens
means aren`t as confident and their deterministic runs remain less
aggressive looking as well. Regardless of model preference, there
is enough agreement at this point to have some confidence in pcpn
returning in combination with cooler and gusty conditions Monday
evening into Tuesday.
&&
.AVIATION...(For the 06Z TAFS through 06Z Thursday night)
Issued at 1130 PM EDT Wed Apr 14 2021
Expect cigs and visibilities to continue to trend toward IFR
overnight as round of deeper moisture pivots back south on west
side of slowly departing upper level low pressure. Will likely see
combination of rain/snow increase in coverage as this deeper
moisture arrives, but not expecting any significant accumulations.
Some improvement expected as we head through today into this
evening, but still looking at mostly MVFR cigs. Winds become
northwest and a bit gusty today.
&&
.MARINE...
Issued at 435 PM EDT Wed Apr 14 2021
Westerly winds will veer northwesterly and strengthen tonight,
continuing thru Thu. These developing nw winds tonight will be
strongest across Lake MI where gusts up to around 30kt are
expected overnight thru at least the morning hrs on Thu,
especially from the Leelanau Peninsula southward. Wind gusts of
20-25kt will likely continue into Thu night. To the e, nw wind
gusts will increase to 20- 25kt in the Lake Huron nearshore Thu
aftn into Thu night. Finally, to the n, wind gusts will increase
to 20-25kt late tonight thru Thu. Winds will then slowly diminish
all areas on Fri.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
LH...NONE.
LM...SMALL CRAFT ADVISORY until 2 AM EDT Friday for LMZ323-341-342-
344>346.
LS...SMALL CRAFT ADVISORY until 8 PM EDT Thursday for LSZ321-322.
&&
$$
UPDATE...MB
SHORT TERM...DR
LONG TERM...JAW
AVIATION...MB
MARINE...DR
Area Forecast Discussion...UPDATED
National Weather Service Corpus Christi TX
631 PM CDT Wed Apr 14 2021
.DISCUSSION...Showers and a few thunderstorms have formed north of
the sea breeze boundary and south of the slowly advancing frontal
boundary south through DeWitt County. Still narrow window for some
stronger storms to form in very unstable air mass as the short
wave trough moves into the region. Severe Thunderstorm Watch
remains in effect until 8 PM. See Aviation section for 00Z TAFs.
&&
.AVIATION...Strong convection will still be possible from BEA to
VCT through 02Z. Storms will be capable of large hail and strong
wind gusts. Expect convection will diminish by mid evening as
convective inhibition increases. Low stratus will return to the
coastal plains by mid-evening with MVFR ceilings. Expect clouds
will lower to IFR/LIFR over the coastal plains along with fog/IFR
vsbys around 10Z ahead of a weak front pushing into the area. The
IFR ceilings will hold through the morning over the coastal plains
behind the front as vsbys improve while ceilings will lift to MVFR
over the Brush Country by late morning. The ceilings will remain
MVFR over most of south Texas Thursday afternoon except for LRD
area where VFR ceilings will exist.
&&
.PREV DISCUSSION... /Issued 340 PM CDT Wed Apr 14 2021/
SHORT TERM (Tonight through Thursday Night)...
Focus in the short term will be severe threat for the northern
Coastal Bend and Victoria Crossroads into early this evening. SPC
mesoanalysis page shows MLCAPE values from 3000-4000 J/kg over the
coastal plains with marginally adequate effective shear of 30-40
knots. Water vapor imagery shows the mid level short wave trough
about to move into the western Brush Country. Convection has
slowly been increasing along a weak low level convergence axis
from a weak sea breeze/surface trough from Mathis to Port Lavaca.
Latest HRRR model continues to forecast convection increasing in
coverage and intensity as the short wave trough approaches. Severe
Thunderstorm Watch is in effect until 8 PM. Expect activity will
diminish by mid evening as CINH increases.
Fog will likely develop over the near shore waters and move inland
into the coastal plains late this evening and overnight ahead of
the weak frontal boundary that will slowly sag to the southern
part of the forecast area by early Thursday morning. The boundary
is expected to stall there and gradually move northward by the
evening hours. Warm air advection will be better over the western
Brush Country Thursday morning to provide a slightly better chance
of convection there. But models show the better lift associated
with an upper level short wave trough moving into northwest Texas
Thursday will be well north of the region. Will only hold on to
slight chance PoPs for the area Thursday. Can not rule out
isolated convection affecting the region Thursday night, but the
same reasoning applies for this period as well as another short
wave trough will be passing well north of the forecast area. Will
keep slight chance PoPs for Thursday night for possible stray
convective development.
Tide levels are running around 1.25 feet above expected along the
Middle Texas coast. Although tides are falling toward low tide,
the swell periods have increased to 9 to 10 seconds. Looking at
Port Aransas web cam, the higher periods produced tide running
up closer to the dunes. If the tidal anomalies continue along with
these higher periods, tides will likely reach the dunes at the
next high tide around 12Z Thursday. A Coastal Flood Advisory will
probably need to be issued later this evening or on the mid shift.
LONG TERM (Friday through Wednesday)...
Zonal flow aloft at 250mb with the jet over the Texas Panhandle will
shift eastward through the weekend. Meanwhile, the broad trough will
become a positively tilted trough as a strong mid-level trough
develops over the western CONUS. A mid-level low over the central
Great Plains will push a strong cold front through South Texas
overnight Friday night. Ahead of the front, isolated to scattered
showers and thunderstorms will be possible as isentropic lift and
PWATs over 1.75" (greater than 75th percentile) are in place. CAPE
values 1000-2000 J/kg with very weak to non-existent cap over the
Coastal Bend and Victoria Crossroads may develop a few strong
thunderstorms Friday. Expect greatest coverage in the afternoon,
focused over the northeastern counties. The greatest concern is
whether there will be enough lift support ahead of the front for
convection to spread further southwest into South Texas.
In wake of the front Saturday morning, there are significant model
differences in regards to QPF. The GFS and NAM have much of the
activity south of the area by Saturday morning, keeping the area
dry. Whereas the ECMWF contains noticeable accumulations over South
Texas through the day Saturday, especially over the southern half.
Due to the inconsistencies and lower confidence, have reduced PoPs
Saturday to isolated to scattered showers, with greatest coverage
expected over the waters and southern half. Removed thunderstorm
potential beginning Saturday as there is decreasing PWAT and minimal
CAPE, both surface and elevated based. Precip chances will decrease
north to south through Saturday night.
Kept only isolated showers inland during the day Sunday and Monday
as PWATs decrease to near an inch over the Coastal Bend and Victoria
Crossroads. Greatest confidence and coverage will be over the waters.
High pressure will continue to increase heading into early next
week, allowing for drier conditions to take over with cloud coverage
decreasing. There is uncertainty regarding the progression of a mid-
level shortwave trough Tuesday; the GFS plunges it southward over
South Texas while the ECMWF/CMC keeps it north. Therefore, the GFS
brings rain chances back Tuesday whereas the ECMWF/CMC remains dry.
Only included isolated showers over the waters and Coastal Bend on
Tuesday.
Temperatures on Friday will remain warm ahead of the front with
highs ranging from 80 to 95, before decreasing significantly behind
the front. Highs are expected to range from the mid 60s to mid 70s
Saturday through Monday, with Sunday struggling to reach the 70s.
Lows will generally be in the low to mid 50s Saturday night through
Monday night. Temperatures are hinted to warm up Tuesday with the
possible return of onshore flow and break of clouds. Lastly, minor
coastal flooding remains possible in wake of the front as moderate
to strong north to northeast winds persist.
MARINE...
A weak to occasionally moderate onshore flow can be expected
this evening. Isolated to scattered thunderstorms will move into
the bays and near shore waters mainly north of Rockport late this
afternoon and early this evening. Some of these storms could
become severe with large hail and strong wind gusts. Fog is
expected to redevelop later this evening over the bays and near
shore waters and continue through Thursday morning. A frontal
boundary will move into the coastal waters early Thursday morning
resulting in a weak to moderate northeast flow. Winds will be weak
to moderate easterly Thursday afternoon Thursday night.
Weak to moderate onshore flow will persist through Friday before a
strong cold front pushes through late Friday night into Saturday
morning. This will result in chances for showers and thunderstorms
over the coastal waters Friday through Friday night, with only
chances of showers Saturday through Sunday. Strong north to
northeasterly winds will follow in wake of the front Saturday
morning through Sunday afternoon, causing Small Craft Advisory
conditions. Winds are expected to decrease to moderate Sunday night
and persist through Tuesday. Slight chances of rain return Monday
and Tuesday.
&&
.PRELIMINARY POINT TEMPS/POPS...
Corpus Christi 72 83 71 84 63 / 30 20 20 30 40
Victoria 69 76 67 81 59 / 50 20 20 50 30
Laredo 71 89 73 94 65 / 20 20 20 10 40
Alice 70 85 70 89 62 / 30 20 20 30 30
Rockport 71 79 71 82 64 / 30 20 20 30 40
Cotulla 69 81 71 91 61 / 20 30 20 30 30
Kingsville 72 86 70 88 63 / 30 20 20 20 40
Navy Corpus 72 79 72 82 65 / 30 20 20 20 40
&&
.CRP WATCHES/WARNINGS/ADVISORIES...
TX...None.
GM...None.
&&
$$
TMT/89...AVIATION
Area Forecast Discussion...UPDATED
National Weather Service Austin/San Antonio TX
913 PM CDT Wed Apr 14 2021
.UPDATE...
The cold front is located across the Coastal Plains this evening. Scattered
showers and thunderstorms are occurring along the boundary with most
of our area getting limited activity. The new data suggests for
limited activity to continue late this evening through the overnight.
However, an upper level short wave out of the Mexican mountains
could bring a round of scattered showers and isolated thunderstorms
mainly across the Rio Grande. If the HRRR output verified, isolated
strong to severe storms may be possible by day break. Other models do
bring isolated to scattered showers and an isolated thunderstorm or
two along the Rio Grande but not with the intensity of the HRRR
solution. Will be monitoring closely and providing updates as new
data comes in overnight and early Thursday.
Updated zones forecast product going out shortly to reflect the
changes made this evening.
&&
.PREV DISCUSSION... /ISSUED 603 PM CDT Wed Apr 14 2021/
AVIATION...
/00Z TAFS/
All area terminals are reporting VFR conditions at this time and
this trend is expected through about 02Z Thurs. Afterward, MVFR/IFR
cigs and vsbys are anticipated for the AUS and SAT airports. There is
plenty of moisture available in the area for a quick shower or two
along the I-35 corridor as a cold front sits across the Coastal
Plains overnight into Thursday morning in addition to a quick period
of LIFR around 12Z/14Z. Chances for a thunderstorm or two slightly
increase mid to late afternoon for the AUS/SAT sites. DRT is forecast
to drop to MVFR around 06Z and then going down to IFR/LIFR from 10Z
into the late afternoon.
PREV DISCUSSION... /ISSUED 240 PM CDT Wed Apr 14 2021/
SHORT TERM (Tonight through Thursday Night)...
Biggest concern through the remainder of the afternoon and evening
will be the potential for isolated strong to severe thunderstorm
activity for portions of the coastal plains where a moisture rich
airmass is in place with dew points into the low 70s. Scattered
convection will be expected to initiate along a convergence zone
between the stationary front and the seabreeze interaction coming
off the Gulf coast. With the temperatures already reaching into the
middle to upper 80s with breaks in the clouds, MLCAPE will climb
into the range of 2500 to 3500 J/kg. Areal bulk wind shear is
limited to around 30 to 35 knots but sufficient enough to support
some strong to severe thunderstorms. The latest SPC midday update
has highlighted portions of the coastal plains from just southeast
of Pleasanton to La Grande under a marginal to slight risk. Main
hazards would be large hail and damaging winds. Otherwise, spotty
showers and isolated thunderstorm activity could develop further
west with an eastward advancement with time. The overnight period
likely sees a lull in any thunderstorm activity but anticipate the
continued chance for light showers and patchy drizzle with a low
stratus deck that develops across the area. Otherwise, a very warm
and muggy night is anticipated.
Combination of the lift from the nearby stationary front that may
wobble a bit more south into tomorrow and a ripple within the zonal
flow aloft from a subtle disturbance should help lead to our next
opportunity for scattered convection across the region on Thursday.
This activity will primarily focus across the Southern Edwards
Plateau, Hill County and along the Rio Grande Plains. Much of this
activity will be elevated through isentropic lift. However, near
the Rio Grande, models show that storms be able to root at the
surface where some SBCAPE is modeled to be located. Additionally,
there may also be a conditional risk for the possibility of an
isolated supercell or two coming off the Serranias Del Burro
mountains in Mexico and crossing the Rio Grande river sometime
during the late afternoon or evening. The latest day 2 convective
outlook from the SPC has a marginal risk for isolated strong to
severe storms across much of the region, from Carrizo Springs to
downtown San Antonio to Lavaca county. The main hazard would be
large hail but gusty to damaging winds may also be possible. The
temperatures should remain cooler on Thursday as skies will be
gloomy under mainly overcast skies. Shower and thunderstorm
potential lingers into Thursday night with warm and muggy
conditions.
LONG TERM (Friday through Wednesday)...
Friday a cold front will move through our CWA from northwest to
southeast. This will bring better chances for widespread showers and
thunderstorms. At this time models show only weak instability and any
thunderstorms should remain sub-severe. Showers will linger into
Saturday, but most places should remain dry Saturday. Behind the
front cooler, drier air will move in for Sunday and the early part of
next week. There will be a slight chance for rain along the Rio
Grande early Monday from a weak upper level shortwave trough. The
forecast will then be completely dry through the rest of the period.
The low level flow will be from the north through east into Tuesday
keeping temperatures below normal.
&&
.PRELIMINARY POINT TEMPS/POPS...
Austin Camp Mabry 61 71 63 79 52 / 30 40 40 60 30
Austin Bergstrom Intl Airport 61 72 62 79 52 / 30 40 40 60 30
New Braunfels Muni Airport 64 74 64 82 54 / 30 30 30 60 30
Burnet Muni Airport 59 67 60 78 48 / 20 50 40 60 30
Del Rio Intl Airport 68 81 68 89 57 / 20 40 20 20 30
Georgetown Muni Airport 60 70 61 78 50 / 30 50 50 60 30
Hondo Muni Airport 67 77 65 84 54 / 20 30 30 40 30
San Marcos Muni Airport 63 72 62 80 52 / 30 30 30 60 30
La Grange - Fayette Regional 65 75 65 79 56 / 40 30 40 70 40
San Antonio Intl Airport 66 74 65 81 55 / 20 30 20 60 30
Stinson Muni Airport 67 75 66 82 56 / 30 30 20 50 30
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
Short-Term/Aviation...17
Long-Term...Hampshire
Area Forecast Discussion
National Weather Service Fort Worth TX
759 PM CDT Wed Apr 14 2021
...New Short Term, Aviation...
.SHORT TERM... /NEW/
/Tonight and Thursday/
Scattered showers and thunderstorms are ongoing this evening
across northwestern portions of the FWD CWA. This convection is
occurring near the 850 mb frontal boundary, with the surface
stationary front analyzed along a line from Athens to Waco to
Llano. The environment in which the convection is ongoing is not
particularly favorable for severe weather, with the 00Z FWD RAOB
showing only about 300-400 J/kg MUCAPE and mid-level lapse rates
of only around 6 C/km. Despite this, a few thunderstorms may get
an assist from about 55 KT of effective bulk shear, and could
become capable of producing small hail. Overall though, the severe
weather threat is expected to be low. Thunderstorms should
diminish by midnight, though some low chances for showers and
perhaps an isolated thunderstorm will continue across much of the
area through the overnight hours.
After a break in convective activity during the morning hours,
another round is expected beginning Thursday afternoon and into
Thursday night. Convection should begin near the 850 mb frontal
surface once again over West Texas, with increasing synoptic-scale
ascent from an approaching upper-level shortwave trough aiding in
convective initiation. Steepening mid-level lapse rates and
increasing vertical wind shear will mean a few thunderstorms will
be capable of becoming severe, and SPC has outlined portions of
the FWD CWA within a "Marginal" risk. The greatest severe weather
threat will likely exist across Central Texas and into the Texas
Hill Country/Edwards Plateau region where HRRR forecast soundings
indicate large and curving low-level hodographs (indicative of
effective SRH in excess of 250 m2/s2) and steep mid-level lapse
rates of 7 C/km. Preventing a more robust severe weather episode
is the fact that dewpoints will struggle to get much out of the
50s, limiting boundary layer destabilization, and thus keeping
thunderstorms rooted above the boundary layer. Still, a few
thunderstorms may be capable of producing large hail given the
aforementioned lapse rates and shear.
Godwin
&&
.LONG TERM... /Issued 325 PM CDT Wed Apr 14 2021/
/Thursday Evening through the Weekend/
The end of the work week still appears wet with a strong cold
front likely to come through late Friday into Saturday. Saturday
onward is forecast to be rain/storm-free, with much cooler
conditions though there could be some caveats.
The start of the long term forecast period features some
uncertainty as the PoP and temperatures will largely hinge on the
placement of a surface front. At present time it appears that the
front will slowly lift northward toward the U.S. HWY 79/I-14
corridor between 00-06 UTC Friday (Thursday evening). Mid level
zonal flow is expected to increase upstream across eastern New
Mexico and adjacent parts of the Panhandles. Resultant
cyclogenesis should induce a WAA regime more than sufficient for
widespread convection. PoPs are broad with 50% rain/storm chances
along the Red River. Farther south, confidence is increasing that
a cluster of storms will move from the Big Country through East
Texas and PoPs have been increased into the 60%-70% range. 3 hour
QPF ensemble PMM from the HREF signal a slightly greater coverage
of convection across Central Texas and some of the extended runs
of higher resolution model guidance offers a similar solution.
Moreover, a plume of steeper 700-500mb lapse rates AOA 8 C/km is
expected to overspread from the southwest with MUCAPE increasing
to near 1500 J/kg by 12 UTC Friday and this may support a loosely
organized cluster of storms rooted along the surface warm front
across Central Texas. If convection is rooted along the front,
its location will ultimately dictate where the greatest corridor
of rain amounts and low-end severe potential will reside. The main
hazard would be marginally severe hail, though if storms are
surface based, there may be a risk for a near-severe caliber wind
gust or two.
The warm front will likely make an attempt to surge northward as
surface pressure falls continue to the north and northwest of the
region. Its northward progress, however, may be hindered if a
large mass of precipitation cooled air remains entrenched across
North and East Texas. That being said, there`s enough of a signal
to increase MaxTs across Central Texas by several degrees with a
1-2 degree nudge upward elsewhere from the previous forecast
cycle. If convection isn`t as widespread, then 75th and 90th NBM
MaxT values may be a more appropriate forecast (with widespread
upper 70 to mid 80 degree weather). It should be mostly cloudy for
most (though the cloud cover forecast has been tricky the past
few days) so we`ll be relying almost exclusively on WAA. However,
if clouds thin, then these greater MaxT`s in the higher percentile
NBM will likely score better. The greatest rain/storm chances
through the day on Friday will shift to the north and east with
what should be widespread rain/isolated storm chances. It looks
like the greatest instability will remain south of the I-20
corridor, so any severe weather threat (likely low/isolated)
should be confined to this region. Again, we`ll watch the
progression of the warm front.
By Friday evening and into Saturday morning a strong cold front
should plow through all of North and Central Texas. Unlike earlier
this week, surface pressure rises of 2-2.5 mb/hr coupled with cold
air upstream will drive the front south through the western Gulf
of Mexico. Sustained winds and wind gusts overnight Friday into
early Saturday could necessitate a Wind Advisory for parts of the
area. Speeds and gusts will approach 25 MPH and 35 MPH,
respectively and add a chill to the air. Saturday will be cool,
cloudy, breezy, but dry with daytime highs struggling to get out
of the low 60s based on the current forecast. Again, if cloud
cover thins, it`s conceivable that sunshine erodes the cooler near
surface layer and temperatures may approach NBM75/90th percentile
with highs in the 60s and 70s.
Chilly conditions will persist late this weekend into early next
week with the coolest night appearing to be early Monday morning.
High pressure settling in across West Texas should equate to a
looser surface pressure gradient. Clear skies and a dry airmass
will be ideal for radiational cooling and I`ve hedged toward the
"cooler" end of the guidance envelope with lows in the mid 30s to
low 40s. Some patchy frost will be possible, especially for some
of the rural and sheltered regions---particularly west of I-35
and north of I-20.
The forecast for next week remains dry, but as we transition out
of our mid-level Omega pattern into more of a Rex pattern, there
will likely be a conveyor of additional upper level troughs from
the southwest. The forecast remains dry for now given the high
probability that our weekend front will push much of the moisture
needed for rain southward. Stay tuned!
Bain
&&
.AVIATION... /NEW/
/00Z TAFs/
SHRA/TSRA are ongoing this evening northwest of a KGLE-KGZN north
of a stationary front stretched across Central TX. While direct
impacts at TAF sites appear unlikely given the weakening trend and
sparse coverage of this convection, some impacts will continue
within the Bowie arrival gate as well as for northbound and
westbound departures. Convective coverage should wane further
after 06Z. CIGs are MVFR across much of the region as of 00Z, but
will decrease to IFR after 06Z, persisting through at least 15Z.
An improvement to MVFR appears likely during the late morning
Thursday, but OVC skies around 015-020 will persist. Another round
of SHRA/TSRA appears likely to approach from the west after 21Z,
but timing/coverage at all TAF sites is uncertain at this time.
Otherwise, look for NE winds gradually veering from the E at 8-12
KT through the period.
Godwin
&&
.PRELIMINARY POINT TEMPS/POPS...
Dallas-Ft. Worth 57 69 56 66 47 / 50 50 80 70 10
Waco 58 70 59 76 49 / 30 60 70 50 10
Paris 52 68 51 58 46 / 40 20 80 80 20
Denton 53 67 54 63 42 / 60 50 80 80 10
McKinney 54 69 54 63 45 / 50 40 80 80 10
Dallas 57 70 56 66 49 / 50 50 80 70 10
Terrell 54 71 56 66 46 / 40 40 80 80 10
Corsicana 57 71 58 70 48 / 40 50 80 70 10
Temple 58 69 60 79 48 / 30 70 70 50 10
Mineral Wells 53 64 56 68 44 / 50 70 70 60 5
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
Area Forecast Discussion...UPDATED
National Weather Service North Platte NE
616 PM CDT Wed Apr 14 2021
.SYNOPSIS...
Issued at 335 PM CDT Wed Apr 14 2021
H5 analysis this morning had a longwave trough of low
pressure across the CONUS. Within this trough a tandem of lows were
noted over the northern half of the CONUS. The first low was
centered over western portions of the UP of Michigan, with a second
low centered over northeastern Nevada. Downstream of this second
low, a decent shortwave was noted over the Nebraska Panhandle. This
feature spread some light snow to western portions of the forecast
area earlier this morning with some light accumulations noted from
North Platte to south of Thedford and points west. At the surface,
low pressure was noted over southern Utah. A frontal boundary
extended southeast of this feature into northern portions of Mexico
and deep south Texas. Further north, a trough extended from
northeastern Montana into south central Nebraska. East of this
trough, winds were northwesterly, while west of the trough, winds
were from the northeast or east. Skies were mainly cloudy across
western and north central Nebraska this afternoon and 2 PM CDT
temperatures ranged from 34 at Gordon to 43 at Imperial.
&&
.SHORT TERM...(This evening through Thursday night)
Issued at 335 PM CDT Wed Apr 14 2021
In the short term, the potential for accumulating snow, and
widespread precipitation, mainly over the western 2/3rds of the
forecast area are the main forecast concerns. Conditions will be
relatively quiet this evening, as not much in the way of lift
exists across the western forecast area. Also, we will be dealing
with some dry air on the southern periphery of surface high
pressure located over the Dakotas. This feature will then weaken
overnight, while at the same time, surface low pressure will
deepen over southern Colorado. This will lead to increased
easterly winds across the forecast area overnight into Thursday.
Overnight tonight, as the H5 low migrates into Utah, downstream
isentropic lift will increase from eastern Colorado/western
Kansas, into eastern Wyoming/western Nebraska. This shows up
nicely on the 300K thetae surface. This isentropic lift will
persist into the afternoon hours across the southwestern and
western forecast area. With good lift noted into the afternoon
hours, increased pops, as well as qpf`s as the models are trending
higher with their forecasts. As for snow potential on Thursday,
temperatures will remain cool, especially in the western half of
the forecast where overcast skies are expected. Locations in the
western part of the forecast area will see a window of
"opportunity" for snowfall on Thursday, mainly west of highway 61.
Accumulations will be light however, given the daytime timing of
the initial surge of lift. This could end up as a case of where we
see snow off and on all day in the far western forecast area, but
little in the way of accumulations. Better chances for
accumulating snow will arrive Thursday night as temps cool back
into the upper 20s/around freezing. The upper level low will track
into eastern Colorado Thursday evening. Isentropic lift will
increase once again from southwestern into western Nebraska,
leading to good precipitation formation. The 300K GFS isentropic
chart indicates robust lift across the western third of the
forecast area late Thursday night into Friday morning. Cross
sections taken from northeastern Colorado into southwestern
Nebraska indicate strong lift from 03z-09z Friday. Some of this
lift is vertical in nature with negative EPV noted, which would
favor bursts of snow with moderate to heavy intensity,
particularly overnight Thursday night. As for snow accumulations,
forecast temperatures favor not much in the way of snow
accumulation Thursday afternoon with temps in the middle to upper
30s in the west. Temperatures will quickly cool into the lower 30s
Thursday evening with upper 20s expected overnight leading to a
much better setup for snow to accumulate. With this in mind, about
80/90 percent of the snow accumulation will occur between 00z-15z
Friday. With this forecast package, QPF`s have trended higher in
the GFS and NAM12 solns and is supported by the 12z HRRR this
morning. With higher QPF`s forecast, increased snow amounts
Thursday night. This yielded the potential for 6+ inches, mainly
west of highway 61. For this reason, will hoist a winter storm
watch for Sheridan, Garden, Deuel, Grant, Arthur, Keith, Perkins
and Chase counties. East of these counties to south of Highway 2
and west of highway 83, accumulations are more on the order of 2
to 4 inches. These areas may end up with a winter weather advisory
depending on how temperatures materialize Thursday
afternoon/evening. The upper level low will track across northern
Kansas on Friday. Meager isentropic lift will continue across
central into eastern Nebraska with the threat for precipitation
continuing into Friday evening. Temperatures will warm into the
upper 30s to around 40 Friday afternoon, which will facilitate a
mixture of rain/snow or changeover to all rain Friday afternoon.
.LONG TERM...(Friday through Wednesday)
Issued at 335 PM CDT Wed Apr 14 2021
We will see a slight warmup Sunday into Monday, followed by a
strong FROPA Monday afternoon into Monday night. Good mid level
frontogenesis will trail the front Monday night into Tuesday with
the next threat for rain/snow across the area. Dry and cool
conditions will follow behind the front Tuesday night/Wednesday
with temps well below normal.
&&
.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
Issued at 616 PM CDT Wed Apr 14 2021
A storm system affecting WY and Colo this evening will move east
tonight and begin affecting wrn Nebraska around 09z Thursday
morning. IFR/MVFR in -RASN and low ceilings is expected to become
widespread along and west of highway 83 by 00Z Thursday evening.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
Winter Storm Watch from Thursday afternoon through Friday
morning for NEZ004-022-023-035-056>058-069.
&&
$$
SYNOPSIS...Buttler
SHORT TERM...Buttler
LONG TERM...Buttler
AVIATION...CDC
Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
1102 PM CDT Wed Apr 14 2021
.UPDATE...For 06Z Aviation discussion below
&&
.SHORT TERM...(This evening through Thursday night)
Issued at 311 PM CDT Wed Apr 14 2021
The upper low this afternoon is centered over the Straights of
Mackinac. However, its cyclonic flow extends back to eastern MN,
with one more lobe over energy swinging down from the Duluth area
that`s giving us one last round of scattered showers (of the rain
variety this time!) that will persist into the early evening for
eastern MN and western WI. Tonight, the cyclonic flow pushes off to
the east and for the rest of the short term period, we`ll be stuck
in a no-man`s land between an upper low over the eastern Great Lakes
and another over the central Rockies. This puts us in a region of
subsidence and surface high pressure, which means dry weather for
Thursday/Thursday night.
For temperatures, did undercut NBM for highs on Thursday, keeping us
stuck in the 40s once again. In this cool/cloudy airmass, the NBM
has consistently been highs, so pushed highs for
tomorrow closer to what the HRRR has. We should see some sunny skies
develop in the afternoon over WI, so if anywhere is going to sneak
into the 50s on Thursday, that is where it will be.
.LONG TERM...(Friday through Wednesday)
Issued at 311 PM CDT Wed Apr 14 2021
Gloomy, cool weather continues Friday into Saturday as weak flow
aloft keeps our persistent air mass stationary. However, a weak
trough is forecast to push through Saturday night, bringing
northwest flow afterwards. This will help clear out clouds and make
for a sunnier Sunday. The weekend`s weather looks somewhat similar
as previous forecasts with dry conditions continuing through Sunday.
However, with past forecasts underestimating the coolness of the
current air mass and latest guidance trending downward, have decided
to slightly lower high temperatures Friday through Saturday. Lows
will be in the 30s while highs are in the upper 40s to lower 50s.
Sunday`s highs are still a little in question with the timing of a
cold frontal passage Sunday night.
Our next chance of precipitation arrives Sunday night into Monday
with said cold front. A trough within the northwesterly flow is
forecast to swing through the Northern Plains. However, model
differences exist in the evolution of this feature. The GFS has been
trending with a tighter, faster trough; spinning up a relatively
impressive surface cyclone that travels through ND, northern MN, and
into Lake Superior by Monday afternoon. Interestingly, the GFS`s
precip along the trailing cold front is rather meager compared to
what one would expect with such a wound up system. On the other
hand, the ECMWF has persisted with a slower, weaker solution
delaying surface low development until the early Monday morning over
northern WI. In turn, with less surface organization the ECWMF just
lazily moves a cold front with widespread, light precip through
MN/WI. NBM produces 20-30% PoPs across the region Sunday night into
Monday afternoon along the front. With still uncertainty with precip
timing and coverage, have opted to not make any changes. Regardless,
QPF amounts should be rather light with maybe a tenth or two of an
inch forecast. It should be mentioned that light snow is possible
during the nighttime/morning hours when temperatures are coolest
before a changeover to rain occurs.
Monday and Tuesday also look pretty cool as another shot of arctic
air follows the cold front. Have lowered high temperatures rather
substantially to the NBM 50th percentile based on latest model
trends, resulting in highs of upper 30s to mid 40s across the CWA.
It remains to be seen how long we will stay stuck in this cool
pattern, as northwest flow looks to continue past mid-next week.
&&
.AVIATION...(For the 06Z TAFS through 06Z Thursday night)
Issued at 1102 PM CDT Wed Apr 14 2021
TAFS are tricky given model guidance is proving to be on the
pessimistic side so far this evening. Do think ceilings will
eventually lower, but probably not as extensively to IFR overnight
as previously expected. Ceilings look to be a bit slower to
lower/thicken across eastern sites, so have delayed the arrival of
IFr ceilings by several hours. Otherwise, VFR looks to return at
eastern sites for Thursday afternoon, with MVFR lingering at western
sites.
KMSP...
Slowed down the arrival of MVFR to 08Z, and there is a chance
ceilings could stay above 1700 feet overnight. Confidence is low, but
trends are looking more optimistic to stay above IFR.
/OUTLOOK FOR KMSP/
FRI...Chc MVFR cigs. Winds N 10Kts.
SAT...VFR. Winds N 10-15kts.
SUN...VFR. Winds NW 10-15kts.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...None.
WI...None.
&&
$$
SHORT TERM...CTG
LONG TERM...MPG
AVIATION...LS
Area Forecast Discussion
National Weather Service Shreveport LA
1044 PM CDT Wed Apr 14 2021
.UPDATE.../Tonight/
Weak disturbances in near-zonal flow aloft continue to provide
just enough isentropic lift to result in patchy drizzle across
portions of the region and some heavier shwrs/tstms across our nrn
areas. Have made some updates to PoPs accordingly, particularly
across our nrn areas to account for the ongoing convection. As for
temps overnight, current temps continue to hover in the mid 50s to
mid 60s, with dew points in the 50s and 60s as well. With low
clouds continuing to linger, temps likely to be warmer than
previously fcst. Have made some adjustments to min temps as well
to warm them by a couple of degrees. Otherwise, no other major
changes are expected attm. /12/
&&
.PREV DISCUSSION... /issued 738 PM CDT Wed Apr 14 2021/
AVIATION...
MVFR/IFR cigs continue to persist across much of the region this
evening, with little to no improvement expected overnight. In
addition, some patchy light rain or drizzle may bring lowered
vsbys to KTXK, although have left mention out attm. Cigs should
gradually lift to VFR from nw to se after sunrise Thursday. Winds
will continue out of the ene at around 10 kts or less through the
pd. /12/
&&
PREV DISCUSSION... /issued 254 PM CDT Wed Apr 14 2021/
SHORT TERM.../Tonight through Thursday Night/
Subtle forcing from weak shortwave energy in southwest to westerly
flow aloft continues to migrate to the east this afternoon, taking
most of the precipitation with it. Sfc cold front has slid just
south of the I-20 Corridor attm and will continue to make steady
progress southward through the remainder of the afternoon into the
evening hours. While upper ridging is noted overnight upstream of
present weak shortwave energy, there are weak perturbations in the
nearly WNW to zonal W to E flow across the Southern Plains
overnight into early Thursday and some medium range progs in
addition to the HRRR are picking up on some precipitation moving
out of the Upper Red River Valley and moving in our northwest
zones or the Middle Red River Valley overnight. Kept chance pops
mentioned overnight across our northwest zones and slight chance
pops elsewhere and kept mention of isolated thunder given the
mid-level lapse rates.
We will likely see a narrow window of not much in the way of
precipitation on Thursday but as we transition into Thursday
Afternoon and especially Thursday Evening, a much stronger
perturbation in nearly zonal flow should provide the necessary
forcing for increased precipitation coverage but we will need to
saturate the air column from the top-down so saturation may not be
a quick process on Thursday during the day but quickly saturate
the column Thu Evng into the overnight hours.
Concerning temperatures, given the cool easterly to northeasterly
winds at the surface, abundant cloud cover and precipitation
chances through the short term, stayed on the cooler side of
guidance tonight through Thursday Night which is a few degrees
lower than NBM values. /13/
LONG TERM.../Friday through Wednesday/
By Friday morning, the persistent omega blocking pattern across much
of the northern CONUS will continue to gradually break down with the
western trough opening up and slowly ejecting eastward out over the
Plains. This will help usher a shortwave into our region and provide
for increased forcing to initiate widespread showers and scattered
thunderstorms through the day on Friday and on into Friday night.
Due to the lack of instability in our cooler post-frontal air mass,
no severe weather is expected at this time as thunderstorms will be
mainly elevated. As the shortwave pivots eastward through Saturday
morning, most of the convection will come to an end although some of
our southern zones south of I-20 may hold on to some lingering light
showers through Saturday. However, confidence is generally low on
this possibility with dry conditions expected to eventually return
areawide for most of the upcoming weekend. Unfortunately, it doesn`t
appear that we will lose the cloud cover at all Saturday with some
sunshine finally returning on Sunday. Temperatures will generally be
slightly below normal through the weekend with highs in the 60s and
lows mainly in the 40s.
Another fast-moving shortwave will pass just north of the region on
late Sunday into Sunday night and help to clear out the lingering
cloud cover Sunday night into Monday morning. With high pressure at
the sfc, this will keep overnight temperatures running well below
seasonal averages with low to mid 40s expected and even some of our
northern zones in the upper 30s. The high will shift east on Monday
with SW flow aloft gradually increasing through Monday afternoon and
Monday night. As a result, cloud cover will begin to increase once
again but we should remain dry through mid week ahead of another
cold front dropping south. For now, the forecast remains dry due to
low confidence of any convection given the relative lack of moisture
in place through next Wednesday. /19/
&&
.PRELIMINARY POINT TEMPS/POPS...
SHV 54 71 53 63 / 30 20 60 90
MLU 54 70 51 63 / 30 10 50 70
DEQ 50 67 49 60 / 50 20 60 90
TXK 51 67 50 61 / 40 20 60 80
ELD 49 67 48 61 / 40 10 50 70
TYR 55 69 54 66 / 30 40 70 90
GGG 54 69 53 64 / 30 30 70 90
LFK 57 72 57 70 / 40 40 60 80
&&
.SHV WATCHES/WARNINGS/ADVISORIES...
AR...None.
LA...None.
OK...None.
TX...None.
&&
$$
12/13/19
Area Forecast Discussion
National Weather Service Tallahassee FL
846 PM EDT Wed Apr 14 2021
.UPDATE...
A broad area of gusty stratiform rain continues to drift across
the area this evening. A few thunderstorms will be possible,
particularly in the western Gulf waters and Panhandle later
tonight. These showers and storms should diminish in the early
morning hours as another, more robust round of showers and
thunderstorms approaches from the northwest in the morning.
&&
.PREV DISCUSSION [739 PM EDT]...
.NEAR TERM [Through Thursday]...
Strong thunderstorms will be the main concern for the next 24
hours. The radar presentation of storms coming in from the west
will appear to weaken over the next few hours, but entrainment of
dry low-level air will enhance gust potential more than one might
guess with a casual glance at radar.
Mariners and beach goers will want to watch the batch of storms
that is now moving east past the mouth of the Mississippi. All
day, the hourly HRRR runs have been showing gust potential of
35-50 knots as theses weakening storms reach the Gulf waters west
of Apalachicola. Over land, gusts may not be that high, but gusts
will still overperform based on a mere glance at radar or the sky.
For Thursday, storms will develop in advance of a slow-moving cold
front that will sag south through the tri-state area. SPC has now
expanded the Marginal Risk in the convective outlook to include
all of our FL counties and the far southern tier of counties in
Georgia. There should be plenty of instability, and there will be
respectable mid-level speed shear. This should support a risk of
isolated severe gusts and hail. Tornadoes are not much of a
concern, given a lack of low-level shear and perhaps an elevated
component to the convection. Storms will develop in place over SE
Alabama and the FL Panhandle early in the morning. The front will
move southeast through the day and exit Dixie County by late
afternoon or early Thu evening.
.SHORT TERM [Thursday Night Through Friday Night]...
Thursday`s slow-moving cold front will drag south into the Gulf on
Thursday night and turn up stationary on Friday. Here to its
north, there will be a lull in rain chances from Thursday night
into Friday morning.
A return of southerly flow is expected on Friday night, as low
pressure starts to develop along the tail end of the front over
the western Gulf. This will start to lift the eastern Gulf portion
of the front back north as a warm front. Rain and thunder will
start to blossom again.
.LONG TERM [Saturday Through Wednesday]...
Warm front will lift north into the tri-state area on Saturday,
bringing the next shot of rain and thunder as a low pressure wave
ripples east past the forecast area.
In the wake of the low pressure ripple, the front will shove back
south over the Gulf and the northern FL Peninsula. Our AL/GA
counties will dry out nicely on Sunday, but rain may keep going
over the eastern Big Bend through Monday night.
The front to our south will weaken next Tuesday and Wednesday, as
upper heights rise modestly and flow becomes more unremarkably
zonal. Even the eastern Big Bend comes up with a dry forecast by
late next Wednesday.
.AVIATION...
[Through 00Z Friday]
Messy taf period on tap with areas of rain and low ceilings moving
into the area this evening through tonight. Periods of rain and
thunderstorms are expected through much of the period at all
sites, with ceilings possibly improving from IFR overnight to MVFR
or even VFR tomorrow afternoon.
.MARINE...
The biggest threat to mariners will come in erratic and gusty
thunderstorm outflow wind gusts this evening, particularly over
the Panhandle waters west of Apalachicola. For the casual
observer, these gusts may seem like a surprise, considering the
convective cells may not visibly appear that strong to the eye or
on radar. However, the presence of dry air beneath the cloud bases
will really increase the gust factor, even from seemingly
innocuous cells. Some of our guidance is showing gust potential of
40-50 knots offshore near convective cells this evening. Small
craft operators should think twice before venturing far offshore
this evening.
A cold front will sag south across the waters on Thursday,
bringing a fairly widespread round of strong thunderstorms. That
front will stall out across the northeast Gulf on Thursday night
and Friday. Then a frontal wave will develop off to our west on
Saturday, causing southerly breezes to freshen as the wave moves
east from the Panhandle to northeast Florida.
North and northeast breezes will prevail early next week as a
surface high moves by to the north.
.FIRE WEATHER...
A slow-moving cold front will sag south across the region on
Thursday. It will be accompanied by numerous strong thunderstorms.
Slow movement of the front will enable a widespread wetting rain.
A break in the rain is likely on Thursday night, then more rain
will return on Friday and especially Saturday.
.HYDROLOGY...
Flooding concern has lessened for Thursday. Rainfall forecasts are
now in the 1-1.5 inch range, which should be manageable.
The next heavier round of rain is expected on Saturday. Forecast
rainfall is mostly in the 1-2 inch range, while river guidance
shows it would take nearly 4 inches of rain to bring most river to
minor flood. 4 inches is not out of the question, but this is an
outlier possibility at this point. Certainly, there will be rises
on rivers this weekend and early next week, but river flooding is
unlikely.
.SPOTTER INFORMATION STATEMENT...
Spotter activation is not requested. However, spotters are always
encouraged to safely report significant weather conditions when they
occur (while following all local, state, and CDC guidelines) by
calling the office or tweeting us @NWSTallahassee.
&&
.PRELIMINARY POINT TEMPS/POPS...
Tallahassee 64 75 59 74 59 / 50 80 20 30 50
Panama City 67 75 59 73 61 / 60 80 10 40 50
Dothan 63 74 54 68 55 / 60 80 10 30 70
Albany 63 75 54 71 55 / 40 90 10 20 60
Valdosta 63 76 57 73 57 / 50 80 20 30 40
Cross City 62 78 62 79 61 / 10 60 40 30 20
Apalachicola 66 74 62 72 62 / 60 70 10 40 30
&&
.TAE WATCHES/WARNINGS/ADVISORIES...
FL...High Rip Current Risk until 11 PM CDT this evening for Coastal
Bay-South Walton.
GA...None.
AL...None.
GM...Small Craft Advisory until 4 AM CDT Thursday for Coastal waters
from Mexico Beach to Okaloosa Walton County Line FL out 20
NM-Waters from Mexico Beach to Okaloosa Walton County Line
FL from 20 to 60 NM.
&&
$$
UPDATE...Merrifield
NEAR TERM...Haner
SHORT TERM...Haner
LONG TERM...Haner
AVIATION...Merrifield
MARINE...Haner
FIRE WEATHER...Haner
HYDROLOGY...Haner