Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 03/31/23
Area Forecast Discussion
National Weather Service Amarillo TX
706 PM CDT Thu Mar 30 2023
...New AVIATION...
.SHORT TERM ...
(This evening through Friday night)
Issued at 100 PM CDT Thu Mar 30 2023
High-end critical fire weather conditions are expected today in the
western combined Panhandles. High-end critical fire weather
conditions are expected again tomorrow for the south half of the
area. High wind and blowing dust will be a concern for travel on
both days. There`s a very small chance for a thunderstorm this
evening. If a thunderstorm does develop, it may become severe with
hail as a primary hazard.
A lee surface low will be intensifying through the day, tightening
the surface pressure gradient. Toward the late afternoon hours, a
700mb jet will develop over the area and particularly the northwest.
That area will also have subsidence aloft from the right exit region
of an approaching 500mb jet streak. All of these factors support a
very dry, very windy, and warm day for the northwest combined
Panhandles. 30-40 mph sustained southwesterly winds are expected
there, though wouldn`t be surprised if winds can be sustained over
40 mph at times. As the 700mb jet comes in, there will be a window
for wind gusts to approach 60 mph, with a very small chance (<20%)
for gusts to exceed 60 mph. The southwest Texas Panhandle will need
to be watched, too, for strong winds, blowing dust, and fire
weather. 30-35 mph sustained winds are expected, gusting up to 50,
with very dry conditions.
A dryline will be set up over the eastern portion of the area today.
50 degree dew points will be in place east of the dryline, though
there will be a strong cap just above 850mb. There`s a very small
chance for the cap to weaken just enough for a thunderstorm to
develop this evening. If one does, it would be toward the eastern
edge of our CWA and therefore may not be mature enough to reach
severe strength by the time it moves out of the area. All that said,
a severe thunderstorm is in the realm of possibilities with the
primary impacts being damaging winds and hail, but it`s unlikely.
However, will need to watch the stream of cirrus observed over the
southern half of the area this morning as that may slightly stunt
daytime heating/mixing just enough to leave the cap too strong to
breach.
Subsidence related to the 500mb jet streak and mixing related to 20-
30 mph southwesterly winds may keep sporadic strong wind gusts going
through the evening. However, any gusts that can continue through
the evening should be weakening in magnitude and frequency. A
Pacific front will move through the area between roughly 1am Friday
through 5am. This front will wipe out much of a nocturnal inversion
that developed over the south half of the area, though a weak near-
surface inversion may remain. Surface pressure gradient will tighten
up again behind the Pacific front, and westerly winds are expected
to strengthen to 20-25 mph.
It may only be an hour or two after sunrise when strong wind gusts
begin, because the shallow near-surface inversion won`t last long
as the onset of daytime heating and breezy westerly winds should
erode the inversion and we should begin mixing. A 50-60 mph 700mb
jet will be set up over the southern half of the area through Noon
on Friday, though it may be a challenge to mix to that level by
then. The 700mb jet will move out in the afternoon, though 40-55
mph 700mb winds will remain. We`ll also be in the left entrance
region of the departing jet streak, which should help with
subsidence and bringing stronger winds to the surface. 30-40 mph
sustained westerly winds are expected with gusts up to 60 mph in
the southern half of the Panhandles. Winds will begin to die down
in the late afternoon as the system departs.
&&
.LONG TERM ...
(Saturday through next Wednesday)
Issued at 100 PM CDT Thu Mar 30 2023
Dry and warm conditions are expected through the long term leading
to multiple days of fire weather conditions. First, temperatures
will be near normal on Saturday with RH values falling to around
10 percent in the west to 20 percent in the east. Fire weather
conditions will be limited to the western half to third of the FA
Saturday afternoon. Saturday is looking to be a mostly elevated to
low end critical fire weather day and mostly RH driven. Winds are
progged to be in the 10 to 20 mph range out of the south to
southwest.
For Sunday, an upper level shortwave trough is progged to pass
over the far southern FA but will not be doing anything for the
combined Panhandles. This shortwave is not expected to trigger any
rain until it is well east of the Panhandles. A LLTR is progged to
set up over the area going into Sunday afternoon with H85
temperatures reaching 20 to 22 degrees C. Higher winds aloft will
be lacking a bit with the jet stream displaced to the north.
However, breezy downsloping winds will bring in some drier air
with Tds falling into the lower teens across the west. The warm
H85 temperatures will help temperatures rise into the upper 70s
and lower 80s. This in turn will lead to RH values falling into
the upper single digits and bringing forth RH driven elevated to
low end critical fire weather conditions on Sunday afternoon in
the west.
Monday will continue to be unseasonably warm with temperatures
rising into the upper 80s for portions of the area. H85
temperatures are also progged to warm again to 23 to 25 degrees C.
Hence, the warmer daytime temperatures. RH values are once again
progged to fall into the single digits. These consecutive days of
low RH are expected to worsen the state of fuels enhancing fire
weather conditions. Especially for Tuesday, as the next upper
level trough moves into the Inter Mountain West. The trough will
bring H5 winds upwards of 80 to 110 kts over the FA for Tuesday
afternoon. Surface winds are progged to be on the windy side as
the surface pressure gradient steepens with lee cyclogenesis
taking place in eastern CO. Also, H85 winds are progged to be near
50 kts indicating a wind highlights may be needed for Tuesday
afternoon. Combined that with some warm temperatures, low RH
values, and worsening fuels, wide spread critical fire weather
conditions are expected for Tuesday at this time. This same system
will bring in a cold front Tuesday night leading to a significant
wind shift if any fires do develop Tuesday. The front will bring
in come cooler temperatures for Wed.
36
&&
.AVIATION...
(00Z TAFS)
Issued at 650 PM CDT Thu Mar 30 2023
For the 00Z TAFs, winds will diminish some this evening, then
increase again and become strong and gusty by mid morning Friday
at the terminal sites. Very strong winds will then continue
through Friday afternoon. The earlier issued Aviation Weather
Warning will expire at 01Z this evening for KAMA. Another AWW will
likely be needed for KAMA sometime Friday morning through the
afternoon hours. Periodic episodes of blowing dust are also
expected during this forecast cycle. However, confidence is low as
to whether or not surface vsbys will be impacted at any one TAF
site so have opted to omit from this forecast at this time.
02
&&
.FIRE WEATHER...
Issued at 100 PM CDT Thu Mar 30 2023
High-end critical fire weather conditions are expected today in the
western combined Panhandles. The greatest concern will be in the
FIRE WEATHER...northwest where the highest sustained winds, wind
gusts, and driest fuels are located. In the northwest, sustained
southwesterly winds of 35-40 mph is expected, though could exceed
40 mph. Gusts could reach 60 mph. RH values are expected to be
around 8%, but lower values will be possible. In fact, HRRR
suggests RH less than 5%, which would send the area into low-end
extremely critical fire weather conditions. In any case, any fire
that does start in the west today could get out of control
quickly. Critical fire weather conditions will continue through
the evening, though it will be a lower threat.
High-end critical fire weather conditions continue tomorrow in the
south half of the area. There`s expected to be a 2-3 hour difference
between the strongest winds and lowest RH values, limiting the
potential for low-end extremely critical fire weather conditions.
From 10am-4pm, sustained westerly winds of 35-40 mph are expected
with 10-15% RH. From 4pm-7pm, 25-35 mph westerly winds are expected
with RH less than 10%. HRRR suggests RH may be as low as 4-6%.
Critical fire weather conditions are expected to continue nearly
every day through Wednesday. Read the long-term discussion above for
more information.
Vanden Bosch/Meccariello
&&
.PRELIMINARY POINT TEMPS/POPS...
Amarillo TX 44 64 35 72 / 0 0 0 0
Beaver OK 43 67 29 69 / 0 0 0 0
Boise City OK 36 62 28 68 / 0 0 0 0
Borger TX 47 68 33 73 / 0 0 0 0
Boys Ranch TX 43 66 32 74 / 0 0 0 0
Canyon TX 43 65 34 73 / 0 0 0 0
Clarendon TX 46 67 38 70 / 0 0 0 0
Dalhart TX 37 64 28 70 / 0 0 0 0
Guymon OK 42 66 28 69 / 0 0 0 0
Hereford TX 41 64 33 74 / 0 0 0 0
Lipscomb TX 45 68 31 68 / 0 0 0 0
Pampa TX 45 65 33 70 / 0 0 0 0
Shamrock TX 47 70 37 69 / 10 0 0 0
Wellington TX 48 71 39 70 / 0 0 0 0
&&
.AMA WATCHES/WARNINGS/ADVISORIES...
TX...Blowing Dust Advisory until 9 PM CDT this evening for TXZ001-002-
006-007-011-016.
Red Flag Warning until 1 AM CDT Friday for TXZ001>003-006>008-
011>013-016>018-317.
Red Flag Warning from 9 AM to 10 PM CDT Friday for TXZ001>020-
317.
High Wind Warning until 9 PM CDT this evening for TXZ001-006.
Wind Advisory until 9 PM CDT this evening for TXZ002-007-011-016.
High Wind Watch from Friday morning through Friday evening for
TXZ006>020-317.
OK...Blowing Dust Advisory until 9 PM CDT this evening for OKZ001-002.
Red Flag Warning until 1 AM CDT Friday for OKZ001-002.
Red Flag Warning from 9 AM to 10 PM CDT Friday for OKZ001>003.
High Wind Warning until 9 PM CDT this evening for OKZ001-002.
&&
$$
SHORT TERM...52
LONG TERM....36
AVIATION...02
Area Forecast Discussion
National Weather Service La Crosse WI
1000 PM CDT Thu Mar 30 2023
.DISCUSSION...(This evening through Thursday)
Issued at 319 PM CDT Thu Mar 30 2023
Key Messages:
- Potent spring storm system to bring a wide range of impactful
weather to the region tonight into Saturday morning.
- Severe storms expected over northeast Iowa and southwest Wisconsin
Friday afternoon and evening. The threats from this fast-
moving complex of storms could include damaging winds of 60-70
mph, tornadoes (some possibly strong), and large hail of 1-2".
- Heavy rain potential tonight into Friday night from south-
central Minnesota to central Wisconsin with amounts of 1 to 2
inches likely. River flooding risks along smaller rivers such
as the Black and Trempealeau are on the rise.
- Heavy snow threat from south-central Minnesota through west-central
and north-central Wisconsin Friday night into Saturday
morning. Amounts of 5-10 inches are expected under this snow
band, though confidence in amounts at a given location remain
in flux. Strong winds may result in blowing snow and reduced
visibilities during the times the snow is falling.
FREEZING RAIN THREAT IN NORTH-CENTRAL WISCONSIN TONIGHT:
Surface and satellite analysis shows the warm front and moisture
surge with ~0.7" precipitable water into the Topeka/Kansas City area
steadily moving north. This surge arrives across the area through
the mid-evening spreading north through the overnight with excellent
moisture transport convergence on the nose of the low-level jet,
which is also isentropically lifting. Text book case of elevated
convective forcing with MUCAPE in the CAMs suggesting >0 J/Kg
southwest of I-94 overnight and by sunrise 750 J/Kg into northeast
Iowa. Overall this means showers and thunderstorms should become
widespread overnight. There may be enough moisture convergence
remaining later tonight as this somewhat higher CAPE moves in, and
RAP indicated bulk wind shear from 2-7 km at about 35 kts, to
provide a low severe sized hail threat there.
Further north the surface temperatures will remain quite cool at the
surface. Trends today in the CAM guidance indicate a well formed
deep warm layer aloft building into the area under strong warm air
advection this afternoon and early evening. By mid-evening, the warm
layer will shift into northcentral WI where surface wet-bulb
temperatures will be in the 30-32F range, promoting a scenario of
freezing rain and icing. With the "most likely" precipitation
amounts in the 0.50 to 1.00" range overnight, it will be challenging
to know the impact and how much ice will form. SPC HREF FRAM mean
output from the morning 30.12Z run indicates 0.25-0.50" of ice
accumulation in eastern Taylor county by Friday morning, decreasing
southwestward. Forecast soundings confirm the threat but also
indicate surface T/Td right near freezing. So, a challenging
forecast right on the edge. NBM and HRRR guidance are very similar
with 0.25-0.35" of ice in northeast Taylor county. Continued warming
and higher dewpoints in the morning Friday should diminish the
threat with mainly all rain expected. This will need to be monitored
for an upgrade to an ice storm warning, but for now have issued a
Winter Weather Advisory to cover the threat.
Precipitation is expected to move off or diminish as the main low
shifts into the Plains in the morning.
OVERVIEW...LATE WEEK STORM SYSTEM
The forecast remains on track for numerous weather impacts Friday
afternoon through Saturday morning. The probability of severe
weather south of Interstate 90 on Friday afternoon continues to
increase. Then, gusty synoptic winds and heavy accumulating snow
combine for winter storm impacts north of Interstate 90 Friday night
into Saturday morning. Lastly, river rises are expected this weekend
in response to the heavy rainfall and snow melt from this system.
The Black and Yellow Rivers in Wisconsin have a high likelihood of
reaching flood stage this weekend.
The culprit, a potent low pressure system, is currently located over
the Rocky Mountains near the Colorado/Wyoming border. After ejecting
into the Plains this evening, the cyclone intensifies as it slides
east-northeast towards the Upper Mississippi River Valley. The
following ensues...
STRONG TO SEVERE STORMS LIKELY FRIDAY PM-
There is good agreement in the hi-res models for the warm sector to
set up along and south of Interstate 90 with dewpoints nearing 60
degrees by late morning. As dewpoints climb, the HREF mean surface-
based CAPE builds to 1000-1500 J/kg in northeast Iowa, southwest
Wisconsin, and southeast Minnesota counties that border Iowa. This
is where the highest risk of severe storms in the local area resides.
Little to no CIN is present in model soundings which increases the
potential for storms ahead of the cold front. Storms could initiate
as early as 1 to 2 PM. If supercells form, the hail and tornado
threat increases. Hodographs are mostly linear in model soundings
which indicates no preference between right-moving or left-moving
supercells, but instead highlights the potential splitting
supercells. There is a lot of uncertainty surrounding how many
storms develop ahead of the moisture boundary and what type of
interactions they may have with each other. Storms could split,
merge, or destructively interfere.
A less likely scenario of storms developing and tracking along the
warm front would lead to an increased tornado threat near the
Interstate 90 corridor. It is more likely that storms would become
elevated if they encounter the warm front, making large hail the
primary threat.
A moisture gradient will precede the cold frontal passage, and hi-
res models all show linear storm development along this boundary.
This is where the highest threat for widespread damaging wind lives.
Bowing segments could easily form, especially if/when the squall
line catches up and merges with isolated storms in the warm sector.
The high speed of the squall line itself poses a damaging wind
threat as it will not take much to mix down stronger wind speeds.
The severe weather threat pushes east of the local area by 7 PM with
non-severe showers and storms lingering across portions of the area
through the evening, especially north of Interstate 90.
SNOW POTENTIAL FRIDAY NIGHT INTO EARLY SATURDAY-
Rain transitions to snow from northwest to southeast overnight
Friday as temperatures fall below freezing. There continues to be a
heavy snow threat, especially north of Highway 10 in Clark County,
Wisconsin. The EPS, GEFS, and hi-res models all favor a slightly
different location for the heavy snow band in the deformation zone.
The EPS is a southern outlier, the GEFS is 2-3 counties north of the
EPS, and hi-res guidance is somewhere in between. Because of the
model differences, it is likely that the southern gradient of the
accumulating snow will exhibit a sharper cutoff in higher
accumulations than currently forecast. There is a 50 to 70% chance
of snow rates greater than two inches per hour in the heart of the
heavy snow band. Rapid accumulations will lead to hazardous travel.
Light snow is likely across much of the forecast area into Saturday
morning as the deformation zone rotates around the back side of the
surface low. Light accumulating snow could continue as late as mid-
morning, especially in central Wisconsin.
GUSTY WINDS FRIDAY NIGHT-
Confidence remains high for gusty winds (35-45 mph) Friday night
into early Saturday morning as the strong pressure gradient sets up
on the backside of the surface low and ridge to the west. There is a
high (80%+) chance for 40 mph gusts but the probabilities fall
under 50% for gusts greater than 45 mph. This poses a blowing snow
risk, but the ability for the snow to blow after the snow ceases
falling is less certain given the potential wet nature of the snow.
However, during the falling snow, these is high confidence for
reduced visibilities, even where lower accumulations are forecast.
Winds subside quickly Saturday mid-morning with high pressure
building into the region.
LOOKING AHEAD: ACTIVE PATTERN CONTINUES
A zonal upper-level flow pattern sets up on Sunday and persists into
the new week. Periodic precipitation chances exist with a train of
shortwaves embedded in the mid-level flow. Rain will be the primary
precipitation type except in north-central Wisconsin where cooler
temperatures could lead to some snow or a rain/snow mix, especially
precipitation falls overnight.
Another low pressure system looks likely around mid-week. It is too
early to dive into the details, but all of the ensemble clusters
bring sensible weather to the Upper Mississippi River Valley. The
global deterministic models currently show the surface low tracking
just to the northwest of the forecast area, but there are a lot of
differences in the timing, strength, track, and progressiveness.
&&
.AVIATION...(For the 06Z TAFS through 06Z Friday night)
Issued at 1000 PM CDT Thu Mar 30 2023
CIGS: cigs will lower into IFR/MVFR tonight, continuing to drop to
mostly LIFR/IFR overnight through Fri morning. Some improvement Fri
afternoon, but trends favor keeping low cigs until responsible storm
system exits east Sat.
WX/vsby: scattered/numerous showers expected to develop overnight at
the TAF sites. Could be a rumble or two of thunder. This activity
should wane toward mid/late morning Friday with more vigorous showers
and storms developing by mid afternoon, a few could be strong-
possibly severe (higher threat south of the TAF sites). Will add
VCTS for thunder threat for now. The band of showers/storms looks to
lift north of the TAF sites by late Friday evening, with periods of
rain/snow or just snow overnight. Some snow accums expected.
WINDS: east/southeast around 10 kts (or so) into Fri evening,
becoming north as sfc low exits east. Some LLWS concerns for a few
hours later tonight...mostly from differences in direction from sfc
to 2 kft (roughly 40 kts at top of that layer).
&&
.HYDROLOGY...
Issued at 319 PM CDT Thu Mar 30 2023
Consistent signal, with just a smidge of southward drift, for 1-2
inches of rain along and north of the I-90 corridor should lead to
minor to moderate flooding on many rivers in that area. This will be
exacerbated by snowmelt runoff in the northernmost basins. River
forecasts have steadily increased in their peak crests on the Black,
Yellow, Trempealeau, and Zumbro as confidence increases. There are
certainly some signals for hitting major flood stage, mainly on the
Black river, and those signals are growing. Most of the crest
information suggests late weekend to early next week for the
crests.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...Winter Storm Watch from Friday evening through Saturday
afternoon for WIZ032-033.
Winter Weather Advisory from 10 PM this evening to 10 AM CDT
Friday for WIZ017.
Winter Storm Watch from Friday evening through Saturday
afternoon for WIZ017-029-034.
MN...Winter Storm Watch from Friday evening through Saturday
afternoon for MNZ079-086>088.
IA...NONE.
&&
$$
DISCUSSION...KAA/Baumgardt
AVIATION.....Rieck
HYDROLOGY...Baumgardt
Area Forecast Discussion...UPDATED
National Weather Service Brownsville TX
1047 PM CDT Thu Mar 30 2023
...New UPDATE...
.UPDATE...
Issued at 1035 PM CDT Thu Mar 30 2023
Added 20 percent chance of a shower or thunderstorms for areas
west of I-69C with radar picking up on a few elevated echos. HRRR
is the only model of consequence showing convection the next few
hours but each hourly run has been fluctuating on intensity and
areal coverage. Observations sites from Laredo, Hebbronville and
Zapata have not reported any precipitation and lower cloud cover
has been limited if not totally absent. Brownsville 00Z sounding
shows dry air in the deep mid-layer so would assume most of the
rainfall is evaporating before it reaches the ground. Lighting is
being detected so can not rule out a brief thunderstorm over the
next few hours.
&&
.SHORT TERM...
(Tonight through Friday night)
Issued at 229 PM CDT Thu Mar 30 2023
Temperatures are finally warming into the lower 80s early this
afternoon, as forecast, in the mid/Lower RGV after some fog/mist
and low clouds slowed the climb this morning. HBV and APY still
struggling to reach 70F under thicker cloud cover and without the
benefit, as of yet, of warm advection from SE winds. Made a few
tweaks to temperature trends for the rest of today to try to
capture this.
No major features aloft are evident in the short-term. Winds at jet-
stream level are in the process of backing a bit toward the SW as a
strong trough aloft progresses eastward from the Great Basin. A
minor ripple in the mid-level SW flow has been consistently
portrayed in the NAM/GFS deterministic runs to clip Zapata/Starr/Jim
Hogg counties this evening (03-06Z). NBM slight chance PoPs in this
time/space looked reasonable, so have kept them intact. Otherwise,
not expecting any measurable precip through Friday night, with
atmospheric moisture limited to a shallow layer near the surface.
A low-level jet (30-40KT at H85) is progged to march across the CWA
from west-to-east overnight, as cyclogenesis in the lee of the
Rockies takes place. This jet is not quite as strong as in previous
model runs, but could still keep winds elevated, around 15-20mph,
for areas west of I-69C/Hwy. 281 overnight, including the McAllen
metro. With these winds, and another low cloud deck expected to
form this evening, overnight lows should stay on on the warm side,
in the lower 70s for most locales. The elevated flow should
keep fog from re-forming tonight.
The warming trend continues for Friday, with a breezy to windy day
also in store, ahead of an approaching cold front. Went a shade
below NBM guidance for high temps, but still have upper 80s-lower
90s for all but the coastal/island zones. Wind speeds reach 18-22
knots sustained, with some gusts just above 30 knots, in the usually
windier areas of southern Hidalgo and Cameron counties, but don`t
believe a Wind Advisory will be needed.
The aforementioned frontal boundary sags its way into the northern
Ranchlands Friday night, then most likely will stall. Looks like
another warm and muggy night, with potential for some fog to form,
with light wind speeds in the vicinity of the stalling front.
&&
.LONG TERM...
(Saturday through next Thursday)
Issued at 229 PM CDT Thu Mar 30 2023
The general trend of the long term forecast is mostly dry with above
normal tempeatures. Starting with Saturday, a stationary front is
expected to be just north of Deep South Texas. While PWATs will be
around one and half inches, QPF remains very low, even almost non-
existent. In short, current forecast on Saturday has isolated
showers, mostly for areas west of I-69E. Moving into Sunday, that
frontal boundary will retreat northward and way from Deep South
Texas, taking the rain chances with it. A short wave trough will
move to the north of our CWA with only minor effects being felt for
the region. Southerly winds will return on Sunday which will help
in our next warm up period. Late Monday into Tuesday the pressure
gradient will tighten up as a cold front starts to approach the
area. This will enhanced winds over Deep South Texas, in particular
for the Lower Rio Grande Valley.
The next system will begin to push into the area late Wednesday into
Thursday as a cold front. Current forecast does not have the front
make it through the CWA. Potential is there for isolated showers and
thunderstorms over the area as the front stalls out. Given how far
out this is, there are still opportunities for this forecast to
change as the models continue to reanalyze the front along with the
long wave trough that will be responsible for how far the front
moves through.
As for temperatures, mostly looking at highs in the upper 80s to 90s
for Deep South Texas. However, Monday and Tuesday could see more
widespread triple digits mostly in the Upper Valley and Brush
Country. The lows on the other hand will be in the range of upper
60s to low 70s Saturday through Monday, while Tuesday and Wednesday
will have lows in the 70s for all of Deep South Texas. As for
Thursday, due to the forecasted rain and expected cloud cover
associated with the front, temperatures will be cooler with highs in
the upper 70s to low 80s, while the low temperatures will be in the
upper 60s to low 70s. Once again, there is still plenty of time for
this Thursday forecast to change.
&&
.AVIATION...
(00Z TAFS)
Issued at 631 PM CDT Thu Mar 30 2023
Increasing and lowering clouds overnight with MVFR ceilings
developing. Probability of IFR ceilings is moderate but consensus
shows ceilings approaching and not reaching IFR with KBRO having
the best chances around sunrise Friday. Ceilings are expected to
lift a few hours after sunrise as southerly winds increase to
strong levels with gusts from the south to southeast approaching
35 knots. Winds overnight remain gusty ranging from 15 to 25
knots.
&&
.MARINE...
Issued at 229 PM CDT Thu Mar 30 2023
Now through Friday Night: Marine fog has been slow to dissipate
today, though the overall extent has been difficult to gauge, with
the satellite view obscured by higher clouds. Visibility has finally
improved greatly on the Laguna Madre as of early this afternoon, but
Gulf-facing webcams from South Padre Island still indicating
visibility of less than 1 nautical mile, so have extended the Marine
Dense Fog Advisory through 4PM CDT for the 0-20nm Gulf waters. As
far as winds and seas, Small Craft Exercise Caution (SCEC) is
currently in effect for the Gulf waters, with SE winds of 15-20
knots and seas at Buoy 42020 consistently running around 6 ft., with
an ENE swell of period 8 seconds contributing to the total seas.
Winds tick up again for the Gulf late tonight, approaching 20 knots,
with the Laguna Madre following suit during the daytime on Friday.
Small Craft Advisories may be needed; otherwise, SCEC will prevail
until Friday night, when the pressure gradient slackens ahead of an
approaching (and eventually stalling) cold front.
Saturday through Next Thursday: Generally favorable conditions
for the weekend and Monday morning. However, winds will start to
increase late Monday into Tuesday as the pressure gradient
tightens resulting in Small Craft Exercise Caution conditions for
the rest of the period. Low end Small Craft Advisory conditions
may also be possible late Tuesday into Wednesday.
&&
.PRELIMINARY POINT TEMPS/POPS...
BROWNSVILLE 72 85 71 84 / 0 0 0 10
HARLINGEN 70 88 70 87 / 0 0 0 20
MCALLEN 71 90 71 89 / 10 0 0 30
RIO GRANDE CITY 70 92 71 89 / 20 0 10 30
SOUTH PADRE ISLAND 71 78 70 77 / 0 0 0 10
BAYVIEW/PORT ISABEL 70 84 70 82 / 0 0 0 10
&&
.BRO WATCHES/WARNINGS/ADVISORIES...
TX...None.
GM...None.
&&
$$
SHORT TERM...59-GB
LONG TERM....64-Katz
AVIATION...59-GB
Area Forecast Discussion
National Weather Service Des Moines IA
650 PM CDT Thu Mar 30 2023
...Updated for the 00z Aviation Discussion...
.SHORT TERM.../Tonight through Friday Night/
Issued at 339 PM CDT Thu Mar 30 2023
Forecast Impacts for the week:
...Major storm arrives with significant severe potential/synoptic
wind threat over the region tomorrow
...Warm spring conditions Sunday to Tuesday
...Next major storm next Tues/Wed will be similar to tomorrow
Confidence Short Term: Medium
Questions remain about the initiation timing and location as some of
the higher resolution models are suggesting the location may be
east of I35 or possibly as far east as the I380 corridor to the
Mississippi River. Confidence is unfortunately lower today
regarding the evolution of the timing and placement of the higher
end severe weather this period. Transition day today as warm air
advection now in full force. High pressure already exiting to the
northeast today with large scale system beginning to shed some
energy into the lee of the Rockies. Initial surge includes some
mid level lift which is brought some elevated returns and a few
showers on radar at mid to later morning. A large shield of
stratus is also being advected north into Missouri and has caught
up to Iowa late this afternoon, though we did have some sunshine
in the afternoon hours. Subjective surface analysis at 900 am
shows sfc low pressure near Denver with a warm front extending
east across KS, southern NE and over north central MO. A rapid
increase in dewpoints is occurring in a corridor from Texas north
to northern Oklahoma where dewpoints have already reached the 50s;
around 60 in central Texas. A pronounced dryline has developed
from eastern Colorado to New Mexico and will eventually work
northeast during the night into Friday. H850 subjective analysis
shows a 135 dm low near Cheyenne, WY with a strengthening low
level jet this morning of 45 to 55 kts already from Dodge City to
Topeka. Judging by the height fields, there are about 3 separate
waves embedded in the flow with the strongest low over Wyoming.
Moisture is expanding north out of the Gulf with a 10C area of
dewpoints riding a 40 to 45kt low level jet over southeast Texas.
By 06z tonight, synoptic models are fairly consistent with a
992-995mb surface low over southwest NE with a warm front
extending northeast to the Iowa MN border. Convection will fire
along and just north of the boundary with some thunderstorms
focused into northern Iowa from 06-12z. Though the CAPE/Shear
parameter space varies among the NAM/GFS/Euro/HRRR solutions, the
NAM and HRRR show a few stronger elevated storms near the border.
So, a small hail potential there overnight while most of the
remainder of the forecast area will see lesser chances of some
scattered convection overnight. Both the HRRR and most of the
synoptic models are now suggesting that the dryline will outrun
the onset of convection due to limited mass convergence at the
surface along the trailing dryline. The more ominous models
continue to be the NAM/NAMNest with lesser emphasis in our area
for convection in the GFS/HRRR mainly occurs nearer the
Mississippi River. The Euro/NAM still show initiation closer to
the I35 corridor or just east of here. For now we will still
consider the potential for storms initiating near the I35 corridor
with the higher end potential ramping up as it tracks toward the
Mississippi River. There is the potential that few if any storms
may initiate soon enough to affect our forecast area in central
Iowa and we will need to look at more mesoscale details;
especially the amount of surface convergence, through late evening
tonight into early Friday morning. Given the spread of solutions,
if the earlier initiation takes place, very strong wind gusts and
some tornadoes would still be favored as the primary concerns
with large hail possible as well.
Despite the major uncertainty in initiation, there remains a signal
in the model data over southern Iowa especially into Missouri and
portions of Illinois, where the upper level jet will have a better
chance of descending toward the surface due to increasing subsidence
behind the system. By 18z the surface low is forecast to be near
Spencer with the warm front over northern Iowa. As the system
translates and deepens into far northern Iowa/southeast MN the
dryline/front will race into western Illinois with the trailing
stronger cold front near Ottumwa. Winds at H850 increase to 45 to
55kt over the south with 40kt common south of I80 through 06z while
another burst of higher momentum air will accompany the deformation
axis and band of snow tracking southeast from 06z to 12z. By the
early afternoon, we also will see some increase in fire weather
threat over the south behind the line of storms as drier air mixes
into the region. Have addressed that with a Fire Weather Watch for
18z through 00z in the south third of the area. We will likely need
wind advisories over much of the area during the later day to
overnight periods, but with everything else now occurring will opt
for the mid shift to work that into the forecast. There remains a
conditional chance that jetstream level winds may follow the storms
tomorrow afternoon, but this remains conditional as well. Lows
tonight will drop to the mid 50s; highs tomorrow in the 50s to lower
70s and mins tomorrow night in the lower 20s northwest to the lower
30s southeast.
&&
.LONG TERM.../Saturday through Thursday/
Issued at 339 PM CDT Thu Mar 30 2023
Confidence: Medium
Saturday will remain cooler, but with few changes expected. By
Sunday, increasing warm air advection will move into the region with
a chance for some light precipitation over the area. Temperatures
continue to warm into Sunday and Monday ahead of the next stronger
system to reach the Central Plains. A similar storm in strength and
evolution is anticipated, caveat, looking at the guidance today. The
bulk of the forcing will come through Tuesday into Wednesday with
cooler air heading in for Thursday. Plenty of time to dig into the
details in subsequent shifts as the bulk of todays discussion has
been focused on the impending significant storm and myriad of other
challenges.
&&
.AVIATION.../For the 00Z TAFS through 00Z Friday evening/
Issued at 638 PM CDT Thu Mar 30 2023
VFR cigs will become MVFR within the next six hours with
thunderstorms expected near northern terminals. Low confidence
showers for southern terminals so left out of TAF. Gusty winds
will continue overnight and into most of tomorrow. Thunderstorms
become increasingly likely after 18z and will be focused east.
Winds increase upon thunderstorm passage, gusting to 40kts at
times through the end of the TAF period.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
Fire Weather Watch from Friday afternoon through Friday evening
for IAZ070>075-081>086-092>097.
&&
$$
SHORT TERM...REV
LONG TERM...REV
AVIATION...Jimenez
Area Forecast Discussion
National Weather Service Austin/San Antonio TX
926 PM CDT Thu Mar 30 2023
...New UPDATE...
.UPDATE...
Issued at 921 PM CDT Thu Mar 30 2023
A marginally strong storm cluster is throwing out frequent lightning,
suggesting the SB CAPE value potential to 2000 J/kg is being tapped
into. These storms should continue racing off the NE across the
Coastal Prairies through 1 AM. Little or no activity is depicted
afterwards by the latest NAM and HRRR runs. Updated PoPs and QPF for
the next 4 hours.
&&
.SHORT TERM...
(Tonight through Friday night)
Issued at 104 PM CDT Thu Mar 30 2023
With a moist southeasterly flow at the surface and a moist
southwesterly flow aloft, high PWATs are in place today and cloudy
skies will remain. Isolated rain showers continue this afternoon
over mainly eastern portions of the region, with total QPF less than
0.10". Isolated thunder cannot be completely ruled out, but is
rather unlikely. Temperatures will max out in the upper 60s and 70s
today for most locations, though some southern/southeastern
locations could hit 80.
Cant rule out patchy light rain or an isolated thunderstorm
continuing this evening into tonight mainly over the southern
Edwards Plateau and Hill Country as a weak shortwave move through
the SW flow aloft, but have removed mentionable POPS after 06Z due
to low confidence. If there is any isolated rain late tonight into
early Friday morning it would likely be along and east of US-281.
Look for clearing skies during the day with seasonally warm highs in
the 80s and lower 90s.
Later in the day as a relatively deep upper low traverses the
central to northern Plains and spins up a significant sfc low ahead
of it, a Pacific cold front will move into our region from the NW
during the afternoon. It will take some time to move all the way
across the area, stalling some and likely not clearing the Coastal
Plains until Saturday morning. It should mostly be a dry FROPA, but
there will be a chance for shower and thunderstorm development in
the afternoon and evening across our northeastern areas,
particularly northeast of La Grange to Austin to Burnet. Can`t rule
out some hail or gusty thunderstorm winds in these regions, and SPC
has added a small sliver of Williamson and Lee counties to their
level 1 of 5 risk area. Any storms that develop will exit to the
east by 10pm. By Saturday morning, temperatures will bottom out in
the upper 40s and lower 50s north, with upper 50s to low 60s south.
&&
.LONG TERM...
(Saturday through Thursday)
Issued at 104 PM CDT Thu Mar 30 2023
A steady warm-up begins on Saturday afternoon as temperatures warm
well into the 80s for South-Central Texas. Surface flow will
generally remain east-northeasterly through the day Saturday, but
that will begin to change on Sunday as an approaching shortwave
moves in from the west on Sunday afternoon. This will induce
southeasterly surface flow and breezy conditions on Sunday afternoon
ahead of the 500mb shortwave over central Texas. At this time, SPC
does not have any sort of risk for severe weather over the CWA,
however, I would not be surprised at all to see at least a Marginal
Risk introduced for the Hill Country and perhaps portions of the I-
35 Corridor in the coming days. The reason being? Instability will
be in place, with guidance indicating a moist warm sector and MLCAPE
of 1000-1500 J/kg, 0-6km shear of 50-60 kts, and modest ML lapse
rates of 6.5-7.5 C/km. Additionally, a sfc dryline will slide
eastward through the afternoon and perhaps reach as far east as the
Hill Country, potentially providing a boundary to focus storm
development. This could be a sneaky severe weather day for the
region as these types of setups can lead to some decent wind or hail
reports in the past.
Once any storms clear the region late Sunday night, Monday and
Tuesday look to be downright H-O-T, HOT! We will most certainly get
our first taste of summer-like weather with highs in the 90s
areawide, and triple digit heat over the Rio Grande Plains and
locations just south of the San Antonio metro. Inverted V sounding
profiles and 850mb temperatures in the 22-27 range will result in
substantial mixing down to the surface, along with breezy 10-20 mph
sustained surface winds out of the SSW to SSE both days, temperatures
will easily climb into the 90s. The dryline will work its way
eastward both days, with a sharp contrast in humidity from west to
east. Expect the Hill Country, Edwards Plateau, and Rio Grande
Plains will see dewpoints fall into the 30s and 40s both afternoons,
while the I-35 Corridor and Coastal Plains will see dewpoints hover
in the upper 50s to upper 60s. Both Sunday night and Monday night
will be fairly muggy as gulf moisture returns westward each evening,
along with morning lows dipping into the mid to upper 60s and lower
70s.
Changes are on the horizon mid to late week as a large upper level
trough takes shape over the western CONUS, sending periodic waves of
energy (shortwaves) through the Austin/San Antonio CWA. At this
time, the NBM guidance has some high chance PoPs starting early
Thursday and we will go with that at this time. Confidence isn`t
particularly high at the moment, but there are signals for perhaps
some beneficial rainfall late next week.
&&
.AVIATION...
(00Z TAFS)
Issued at 626 PM CDT Thu Mar 30 2023
A fairly tight pressure gradient causing gusts early this evening
will relax later tonight as surface troughing builds south over the
area. This lowering of winds plus abundant Gulf moisture will lead
to some more IFR cigs as early as midnight over the I-35 Terminals
and closer to daybreak at DRT. A dryline and cold front combo will
bring a faster mixing to VFR skies in the late morning and midday
hours as winds shift to SW then NW to clear out the moisture. No
significant gusts are expected behind the front over I-35, but some
gusts to 30 knots may occur in the late afternoon at DRT.
&&
.PRELIMINARY POINT TEMPS/POPS...
Austin Camp Mabry 69 89 53 84 / 20 20 0 0
Austin Bergstrom Intl Airport 68 89 52 84 / 20 20 10 0
New Braunfels Muni Airport 68 90 55 85 / 20 10 0 0
Burnet Muni Airport 67 86 49 81 / 20 20 0 0
Del Rio Intl Airport 65 90 55 87 / 10 0 0 0
Georgetown Muni Airport 68 88 50 82 / 20 20 0 0
Hondo Muni Airport 67 91 55 86 / 10 10 0 10
San Marcos Muni Airport 68 90 53 84 / 20 10 0 0
La Grange - Fayette Regional 70 86 57 82 / 30 20 30 0
San Antonio Intl Airport 68 90 56 85 / 20 10 0 10
Stinson Muni Airport 70 91 60 86 / 30 10 0 10
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
Short-Term...18
Long-Term...Platt
Aviation...18
Area Forecast Discussion
National Weather Service Grand Rapids MI
1104 PM EDT Thu Mar 30 2023
LATEST UPDATE...
Update
.UPDATE...
Issued at 1104 PM EDT Thu Mar 30 2023
No changes to the going forecast. We are still expecting a round
of showers and embedded thunderstorms late tonight. The latest
runs of the HRRR continue the theme of an increase in
precipitation late tonight and Friday morning. Precipitation
should increase after about 300am, but especially after 500am.
500am to 1000am should be the time frame of the most significant
precipitation. The increase in precipitation is coincident with
the 850mb low level jet working through the area. The max speeds
are centered around 500am when 50-60 knots rolls through the
forecast area. We are not expecting any severe weather, but there
will likely be some embedded thunder. Heaviest precipitation
tonight looks to be over West Central Lower Michigan north of
Muskegon along the lakeshore. HREF probability matched mean
precipitation values are over an inch just between 200am and
800am tonight alone.
&&
.DISCUSSION...(This evening through next Thursday)
Issued at 336 PM EDT Thu Mar 30 2023
- Risk for severe weather Friday into Friday night
The combination of favorable deep layer bulk shear values of over
50 knots...steep mid level lapse rates and a warm front near or
just north of the CWA will raise the risk for the severe weather
potential Friday afternoon into the night. MU CAPE values are
forecast to increase to over 1000 J/kg during this period which
will help to fuel the thunderstorms. The forcing Friday afternoon
may be limited but during the evening that changes as the low
level jet strengthens ahead of a potent mid level wave tracking
through. Also the left front quadrant of a stronger upper level
jet will be in the CWA Friday evening enhancing the lift along the
path of this wave. The instability is elevated Friday afternoon
which would favor hail and perhaps localized high winds as the
main risk. During the late afternoon into the evening hours a
narrow plume of surface based instability may advect in from the
southwest. That would increase the damaging wind risk and also
warrant the potential for an isolated tornado. It is possible that
the surface based instability dissipates as the wave moves
in...it is just too early to say at this point.
- Impactful winds could occur Friday night into Saturday
Wind gusts around the frontal passage Friday evening may top out
over 40 knots in the CWA...especially near any heavier
downpours/convection. Also...the 1-2k ft winds on the backside of
the departing storm are shown to increase to 40 to 50 knots
especially along the lakeshore. The mixing heights reach into
these winds so we could see occasional gusts hitting wind advisory
criteria. As a result...we may see scattered power outages from
this storm system.
- Another strong storm possible Tuesday into Wednesday
An intense low pressure system is forecast to track northeastward
from WI through Lake Superior during this period. Warm and moist
air advection through the CWA will lead to an unstable
environment. Deep layer shear is progged to be quite
strong...especially Tuesday night into Wednesday. Thus an
increased risk for organized thunderstorms may develop. GFS
ensemble QPF values are still showing a lot of spread with the
QPF...but some potential for heavy rain is still shown.
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 817 PM EDT Thu Mar 30 2023
A band of precipitation is working through the area this evening
with both rain and snow occurring as it moves through. This
rain/snow should be north and east of the area by 02z-03z. Other
than some brief MVFR restrictions to visibility, it should not
affect aviation too much.
The next item to watch is a batch of showers and storms that are
forecast to develop off to our west over IA/IL/WI around 04z and
move east. A round of showers and perhaps a few embedded
thunderstorms will move through the TAF sites between 09z and 16z
late tonight and Friday morning. Ceilings will drop precipitously
from VFR levels to IFR and in a few spots LIFR. Visibilities will
predominantly stay MVFR in the rain/fog, but some IFR is possible
especially at MKG and GRR.
Friday afternoon the showers/storms will become more scattered,
but the low ceilings (IFR/LIFR) will hold in place as will the
MVFR visibilities.
Finally, winds will increase out of the south steadily the next
12-18 hours. South winds of 10-20 knots with gusts between 20-30
knots will become common late tonight and into Friday. A strong
core of winds aloft between 06z-15z will create low level wind
shear conditions. Winds at 2,000 feet during this time frame will
be from 200-210 degrees at 45-50 knots.
&&
.MARINE...
Issued at 336 PM EDT Thu Mar 30 2023
The arrival of the warm front and associated low level jet will
generate high winds and building waves over the nearshore waters
tonight into Friday. The wind veer with time from southeast to
south which will support the building waves. Conditions will
become hazardous to small craft.
Then for Friday night into Saturday a deep storm system tracks
through the zones. Gales are looking likely with a low end risk
for storm force winds. Cold air advection Saturday will enhance
the wave buildup with values over 14 ft possible.
&&
.HYDROLOGY...
Issued at 336 PM EDT Thu Mar 30 2023
- Heavy rain possible tonight into Friday night
Modeled PWAT values in the CWA increase to over 1.1 inches Friday
into Friday night. One round of heavy rain looks likely tonight
was the warm front moves in. This feature will be accompanied by a
low level jet...which will enhance the rainfall rates. As the
surface warm front slows down over the northern zones...those
locations may see the most rain through the morning. A second
round of heavy rain is looking likely for later Friday afternoon
into Friday night. This is when the mid level wave and associated
forcing moves. Showers and thunderstorms will be on the increase
then...peaking during the late evening hours. Given the saturated
conditions that will likely exist ahead of this evening surge of
rain...runoff should be efficient. That could lead to urban and
poor drainage issues. Total rainfall from the storm system is
expected to cause steady rises on the rivers. The Muskegon and
Pere Marquette basins are forecast to see the most rainfall from
this system with values over 1.5 inches possible. These values and
location is supported by the latest SPC HREF QPF. This would be
enough rain to generate minor flooding for several sites in the
Muskegon basin.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...None.
LM...Small Craft Advisory until 11 PM EDT Friday for LMZ844>849.
Gale Watch from Friday evening through Saturday evening for
LMZ844>849.
&&
$$
UPDATE...Duke
DISCUSSION...MJS
AVIATION...Duke
HYDROLOGY...MJS
MARINE...MJS
Area Forecast Discussion
National Weather Service North Platte NE
610 PM CDT Thu Mar 30 2023
...00Z AVIATION UPDATE...
.SYNOPSIS...
Issued at 323 PM CDT Thu Mar 30 2023
Key Messages:
-SPC expanded the marginal severe weather risk this evening to
include areas along and east of highway 83. The concern is large
hail.
-Wind gusts of 50 to 55 mph are expected Friday afternoon.
-1 to 6 inches of snow is predicted across nrn Nebraska. Highest
totals are expected across northern Sheridan county.
-The primary concern for Nebraska with the storm next Tuesday is the
potential for high winds Tuesday and Wednesday.
&&
.SHORT TERM...(This evening through Friday night)
Issued at 323 PM CDT Thu Mar 30 2023
The CAMs backed by the HREF show one or more elevated storms
developing this evening as far west as highway 83. Storm motion will
be quick, east-northeast at 50kts and the RAP suggests elevated CAPE
around 1500 J/KG. SPC expanded the marginal severe weather risk
accordingly to include areas along and east of highway 83. The
concern is large hail. This storm activity should commence 02z-03z
with the approach of a warm nose aloft moving northeast out of
KS. Storm activity exits ncntl Nebraska by 05z-06z.
The next concern is the prospect of high winds Friday. The models
are in very good agreement displaying a PV1.5 anomaly near the SD
border Friday afternoon. Across swrn Nebraska, the BUFkit momentum
transfer procedure shows several sites with gusts to 50kt or higher
for a few hours during the afternoon. These gusts will occur just
ahead of a strong cold front advancing south and there is the
potential for convectively induced gusts also. The momentum transfer
should shut off by early evening.
A blend of the NBM 75th percentile winds and gusts would place High
Wind criteria across the srn Sandhills east into Custer county and
then south across Interstate 80. Since the deterministic models
suggest gusts to around 50 mph, wind speeds have been backed down
slightly for gusts to 55 mph and this forecast will be revisited
Friday morning for a possible High Wind Warning.
The models have trended north with the track of a closed h700mb low
placing the low mostly across srn SD Friday. This should preclude
the development of longer lived convectively enhanced snow across
nrn Nebraska- the better QPF is solidly across SD. The concern for
significant Black Hills convergence driven snow continues across
nwrn Nebraska. The RAP, NAM and HREF appear to be favoring the area
between Chadron and Hay Springs for the best snowfall (4 to 6 or
more inches). This is related to the direction of the moist winds
blowing around the hills and it`s worth noting the models show this
area sheltered from the stronger winds predicted south. QPF across
nwrn Nebraska gets a boost from the GFS and SREF leading to totals
of 4 to 6 inches across the Pine Ridge in northwest Sheridan county.
All together, the Winter Storm Watch in effect across nrn Nebraska
will be downgraded to a Winter Weather Advisory with this forecast
issuance.
.LONG TERM...(Saturday through Thursday)
Issued at 323 PM CDT Thu Mar 30 2023
Attention turns to a storm system located across the Gulf of
Alaska this morning which is progged to slice south along the coast
of British Columbia this weekend and be located across WY Monday.
The models are in good agreement tracking the low through nwrn
Nebraska and SD Tuesday. The GFS, ECM and ensembles show the best
forcing and resultant QPF across SD. The primary concern for
Nebraska is mainly the potential for high winds Tuesday and
Wednesday. The storm, 985 mb or deeper in the GEM, GFS and ECM, will
still be swirling across MN Wednesday.
Wind speeds Tuesday and Wednesday have been spiked with the NBM 90th
percentile for speeds 25 to 30 mph and gusts 35 to 45 mph.
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 603 PM CDT Thu Mar 30 2023
Expect both terminals to begin in VFR but rapidly deteriorate by
early Friday morning as the next winter system approaches from the
west. Strong LLWS overnight will translate to afternoon winds
Friday approaching 40 knots from the northwest at both terminals.
For LBF: Will be closely watching potention for convection
developing invof a weak warm front to potentially encroach on
terminal airspace. Will omit for now and monitor closely over next
few hours for possible amendments. Winter impacts will remain
more limited to threat for isolated -SHSN in the afternoon hours
Friday. Given limited coverage anticipated, have covered with a
VCTS mention for now. Low stratus will work in and though signals
exist for IFR criteria, will limit to low-end MVFR for now.
For VTN: Greatest local impacts will occur here as signals suggest
widespread fog and/or -FZDZ arriving by early Friday morning. As
the storm system traverses the area, precipitation in the form of
snow will increase by daybreak with strong winds leading to
blowing snow concerns and visibility restrictions. IFR conditions
are likely with periodic LIFR possible, especially in the
fog/blowing snow periods, so refinements with later forecasts are
likely.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory from 6 AM to 6 PM MDT Friday for NEZ004-
094.
Winter Weather Advisory from 7 AM Friday to midnight CDT Friday
night for NEZ005>008.
&&
$$
SYNOPSIS...CDC
SHORT TERM...CDC
LONG TERM...CDC
AVIATION...NMJ
...Updated Aviation Forecast Discussion...
.DISCUSSION...
Issued at 320 PM CDT Thu Mar 30 2023
Key Messages:
- Isolated thunderstorms with large hail will be possible in parts
of northeast NE this evening and the early morning hours of
Friday. Strong southerly winds are expected over much of the
area tonight, gusts 40 to 50 mph possible.
- Some risk of severe storms Friday, mainly in IA. Chances are
much higher east of our area. Strong northwest winds may gust
over 50 mph for much of the area in the afternoon and evening.
Also, some light snow accumulations possible in northeast NE
Friday afternoon into the evening.
A strong mid level disturbance is located over the western United
States this afternoon. The system had 12 hour height falls in excess
of 100 meters over parts of CA/NV/AZ this morning. That system will
move east toward the western high Plains tonight. Expect that a
closed low with heights around 537 dm at 500 mb will be over
northwest NE by daybreak Friday morning. The center of the low is
likely to reach northeast NE by Friday evening. Snow is likely in
the deformation zone on the north and northwest side of the 500 mb
low, which will track rapidly east through IA Friday evening.
Highest potential for severe storms Friday is east of our area, but
will have to monitor for at least a few isolated severe storms in
our area Friday (highest chances in our local area are across
southwest IA).
Tonight...Strong low pressure center at the surface over the western
high Plains will start to track eastward tonight. Center of the low
could reach near the NE/SD/IA border by 12Z Friday. Strong southerly
winds will occur ahead of the low over much of eastern NE and
southwest IA tonight. A wind advisory was issued earlier for parts
of the area with potential wind gusts 40 to 50 mph.
The airmass in our area will destabilize this afternoon and evening
with MUCAPE values from recent RAP model runs up to about 1500 J/kg.
Isolated strong to severe storms (with potential for mainly hail) may
focus along a low level front in northeast NE to the northeast of
the surface low, but other storms (with lower severe potential) are
possible from eastern KS into southeast NE, northwest KS and
southeast NE. Much of area could be dry after midnight into the
early daylight hours of Friday but will maintain at least some low
POPs for parts of the area.
Friday...This will be a very active day for parts of IA southward to
MO and AR. There does appear to be a window of opportunity across
western IA, some of the convection allowing models (CAMs) show that.
If storms occur in western IA, they will have the potential to
become severe. Look for a big range of high temperatures Friday,
from the lower 40s at the SD border to lower 70s at the MO border.
Will issue a Fire Weather Watch in parts of southeast NE and
southwest IA where Extreme Fire behavior is possible, but not a slam
dunk. RH values could drop to around 25 percent or lower. Wind gusts
could reach 40 mph in the early afternoon and 50 mph late afternoon
into the evening.
Now to the winter weather potential. Some accumulations - under 2
inches - are possible in the northwest part of northeast NE from the
late afternoon into the evening. We may need a winter headline for
that with the snow and potential for reduced visibilities. The
precipitation type will change to all snow showers Friday night.
Saturday through Sunday evening. This period looks dry. Highs should
be mainly in the 50s Saturday, then mostly mid 60s to mid 70s
Sunday. Sunday could be a busy fire weather day, so will keep an eye
on that.
Monday and beyond. We will include some low POPs Monday and Monday
night but it looks much more active Tuesday and Tuesday night. A
strong mid level system (not too much different that the one that
will be in our area in the shorter term) will move through the
region with potential for thunderstorms in the warmer air and
potential for snow once the cold air wraps in from the north and
west.
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 630 PM CDT Thu Mar 30 2023
Another busy set of TAFs are out for the 00z period, with strong
winds ongoing across the KLNK and KOMA TAF sites while KOFK is
seeing lull. Early in the TAF period are some lower end storm
chances (30 to 40%) KOFK and KLNK, but are not high enough to
include in the TAF, with the best chances lying north of the KOFK
area. If storms were to form, they`d be quick-hitting and move in
and out in an hour, with some hail possible. Also early in the TAF
period are MVFR ceilings that are currently in northeastern
Kansas, and should spread north in around 3 hours affecting all
sites. Low-level wind shear should develop overnight as well as 50
kt winds develop at FL016 through sunrise, and winds begin turning
northwesterly Friday afternoon.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...Wind Advisory until 7 AM CDT Friday for NEZ015-033-034-043>045-
050>053-065>068-078-088>093.
Fire Weather Watch from Friday afternoon through Friday evening
for NEZ066>068-078-088>093.
IA...Wind Advisory until 7 AM CDT Friday for IAZ043-055-069-079-080-
090-091.
Fire Weather Watch from Friday afternoon through Friday evening
for IAZ079-080-090-091.
&&
$$
DISCUSSION...Miller/last
AVIATION...Petersen
Area Forecast Discussion
National Weather Service Pocatello ID
837 PM MDT Thu Mar 30 2023
.UPDATE...
Not planning an update this evening although am concerned about
potential for heavier snowfall amounts from upslope flow into the
Pocatello region. Current forecast is for 1 to 3 inches tonight,
which seems reasonable and in line with most model forecasts. But,
upslope flow events can overperform and the HREF is certainly
higher pushing more of a 2 to 5 potential in Pocatello. Picked
apart the HREF members, specifically the HRRR and NAMNest, which
looks to support more of the 1 to 3 line of thought. With that
said, there`s just too much uncertainty to upgrade zone 54 to an
advisory overnight. Will allow headlines set to expire at 3z to
expire and continue other products as advertised, which do include
many of the south highland zones which do support the higher snow
totals tonight.
13
&&
.PREV DISCUSSION... /issued 231 PM MDT Thu Mar 30 2023/
SHORT TERM...Today through Friday Night.
Early afternoon satellite imagery shows a broad area of low pressure
centered over NE Idaho and SW Montana continuing to bring wrap
around bands of snow favoring NW upslope regions. May see a bit of a
rain/snow mix below 5000 feet at times with all precipitation
favored to change over to snow if not already later today. Heavily
utilized the HREF for POPs and QPF with the latest forecast package
with a brief break for S-CNTRL Idaho before one final push of
moisture as the low pulls northeast helping to bring heavier snow
down from the Frank Church in addition to amplifying snow bands
across the lower Snake and ERN Magic Valley south to the Utah
border. By sunset tonight, predominantly dry conditions will return
across CNTRL Idaho outside of lingering mountain snow showers as
heaviest precipitation shifts to along the southern Snake Plain down
to the Utah border.
Have adjusted WINTER WEATHER HEADLINES to support this change in
timing with removing the Island Park and now only light snowfall is
expected in a NW shadowing regime that is unfavorable for bringing
heaviest snow over the Continental Divide. Additional snow across
the ERN Magic Valley and Snake Plain will be between 0.5 to 2 inches
with the potential for locally higher totals in the Pocatello area
dependent on if the band of snow the HREF picked up on hangs around
in the area. Current snow totals in the Pocatello area look to be
between an another 3 to 4 inches but lighter elsewhere in the zone
which will continue to need to be monitored this evening.
Winds from the ERN Magic Valley NE up to the Arco/Mud Lake
Desert are already fairly breezy with gusts to around 30 to 40 mph
which may leading to patchy areas of blowing snow. In the ERN Magic
Valley, South Hills, and Raft River Valley especially, winds will
steadily increase as drier conditions return behind the exit of the
low to the NE bringing wind gusts between 40 to 55 mph to the area.
Have continued the WIND ADVISORY to account for this which goes into
effect this evening through Friday morning.
Breezy winds will continue to work up the Snake Plain throughout the
day Friday staying sub-wind advisory increasing diurnally Friday
afternoon with gusts between 30 to 40 mph shifting northeast into
the Teton Valley. This will lead to areas of blowing and drifting
snow wherever snow is low density enough to be carried with the
mention of patchy blowing snow included. Winds also look to be
strongest in particular around the Botts area of the NRN Teton
Valley downsloping off the Big Holes. Snow showers Friday
afternoon will remain predominantly bound to the higher terrain.
Further to our northwest in the Gulf of Alaska, another broad Pacific
trough will descend along the British Columbia Coast Friday into
Saturday as moisture streams in out of the NW. Snow and wind looks
to be the primary hazards with this incoming system with strong
mountain winds mixing down to the surface as 40 to 50 kt 700 mb flow
leads to widespread strong winds. Will continue to look at products
to handle this event with the brunt of precipitation arriving into
the long term period. For Friday night, snow will first begin
further north before overspreading SE along with the winds. MacKay
LONG TERM...Saturday through next Thursday.
Models remain steadfast on the refusal of winter to let up across
eastern Idaho during the extended portion of the forecast. Saturday
looks to be a rather raw day across the region with widespread gusty
winds, with wind advisories very likely across a good chunk of the
region not already included in a winter weather headline, along with
widespread precip chances. Valley locations will likely see
temperatures warm enough to avoid any snow accumulations. But
locations in the high country may see localized near blizzard
conditions with falling snow and such strong wind. As we get into
Sunday, and especially Mon - Wed, as a potent upper low moves
overhead expect temps to run well below climo with snow chances
across all of eastern Idaho with some ample snowfall likely in the
high country adding to our already high snowpack. Winds will remain
a touch breezy early next week but nothing like what we will see on
Saturday. Winter time pattern COULD break as we get into next
weekend but still time for much to change but maybe some hint of
relief from winter in the close future. McKaughan
AVIATION...For the 18Z TAFS through 18Z Friday.
Upper low over the region keeps widespread cloud cover and precip in
the forecast at all terminals for much of the next day. Overall hit
and miss nature of the activity makes it difficult to pinpoint exact
impacts and timing but overall MVFR cigs will be most common into
the morning hours tomorrow, with some occasional breaks possible. Hi-
res models bring more impactful snow into KSUN, KBYI and KPIH later
this evening with impacts at KIDA and KDIJ potentially less but
still not non-zero. IFR to LIFR reductions quite likely with
heaviest snow activity. KBYI will be the windiest terminal the next
24 hours with gusts nearing 30 kts but KPIH and KIDA will see gusts
nearing 25 kts at times. McKaughan
&&
.PIH WATCHES/WARNINGS/ADVISORIES...
Wind Advisory until noon MDT Friday for IDZ055>057.
Winter Weather Advisory until 3 AM MDT Friday for IDZ056>059.
Winter Storm Warning until noon MDT Friday for IDZ060.
Winter Weather Advisory until 9 PM MDT this evening for
IDZ062>064-067-068-070-075.
Winter Storm Warning until 9 PM MDT this evening for IDZ069-
071>074.
&&
$$
Area Forecast Discussion
National Weather Service San Diego CA
900 PM PDT Thu Mar 30 2023
.SYNOPSIS...
The storm which brought precipitation to the region is exiting to
the east, so we`ll see drier and warmer weather Friday and into
the weekend. Another system will move into California by Monday,
where gusty winds and a chance for light precipitation is
expected. The troughing pattern looks to continue into the middle
of next week, where cooler than average weather will stick around.
&&
.DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE...
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
COUNTIES...
Update:
The showers hung on awhile this evening, but have finally come to
an end. See rainfall summary on our webpage weather.gov/sandiego
A tranquil and chilly night is in store. No changes were needed to
the forecast. See previous discussion below for forecast details.
Previous Discussion:
.SHORT TERM...(Today through the Weekend)...
An area of low pressure spinning off San Clemente Island will
continue to produce isolated showers and thunderstorms for our
region through the afternoon, before winding down by the early
evening. Latest run of the HRRR depicts the last of the showers
diminishing across inland areas this evening. Breezy west winds
will continue for the desert slopes of the mountains through the
evening, calming overnight.
A dry and warmer period will occur Friday into the weekend. Friday
morning low temperatures will be on the cooler side after the area
of low pressure departs with cool northwest flow aloft. Areas of
the high desert into coastal valleys west of the mountains will
dip into the 30s. We`ll warm back into the 60s for areas west of
the mountains and high desert, with 40s/50s across the mountains.
The weekend will warm a bit more with 60s/70s west of the
mountains and 80s into the Coachella Valley and Anza Borrego
desert regions.
&&
.LONG TERM...(Monday through Mid-Next Week)...
A potent trough of low pressure will plunge into the western U.S.
on Monday. There still exists some uncertainty on how strong and
where specifically this feature will go. Model ensemble guidance
continues to point to a slight chance of light rain/snow showers
in the mountains during this time. Confidence is higher, however,
on more cooler weather coming into the picture, along with
stronger winds. This pattern may bring an enhanced shortwave close
to our area with stronger upper level winds, some of which may
surface. Model ensembles indicate coastal areas with wind gusts
25-35 MPH, with higher winds in the mountains. Breezy conditions
may last into Tuesday as well. The middle of next week looks to
favor more troughing and cooler weather.
&&
.AVIATION...
310330Z... SCT to locally BKN clouds with bases 2500-3500 ft MSL
tonight into Friday morning, with patchy fog possible in the
valleys. Clouds and fog gradually clearing Friday morning, with SCT-
BKN high clouds at/above 20,000 feet MSL moving in Friday afternoon.
&&
.MARINE...
Winds and seas will continue to diminish tonight. No hazardous
marine conditions expected Friday through Sunday. Stronger west-
northwest winds gusting over 25 kt and rough seas are possible again
Monday into Tuesday.
&&
.SGX WATCHES/WARNINGS/ADVISORIES...
CA...None.
PZ...None.
&&
$$
PUBLIC...Gregoria (Update)/APR (Previous Discussion)
AVIATION/MARINE...Connolly