Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 05/12/23
Area Forecast Discussion
National Weather Service Amarillo TX
822 PM CDT Thu May 11 2023
...New AVIATION...
.SHORT TERM ...
(This evening through Friday night)
Issued at 229 PM CDT Thu May 11 2023
18z RAP analysis and mid-level water vapor imagery show the
disturbance responsible for last night`s storms currently churning
over SE CO. At the sfc, a 1000mb low has a Pacific front draped
from its center through the eastern Panhandles with drier air
filtering in behind it. Downsloping gradient winds are out of the
southwest at 15-25 mph, gusting over 30 mph at times. The sfc low
will continue to advance eastward through the day and drop a cold
front through the area later this evening. This front will only
have minimal impacts on temperatures, with the northwest portions
of the CWA remaining slightly cooler in the 70s tonight and
tomorrow. Elsewhere, highs will be in the 80s.
The aforementioned cold front will gradually stall somewhere
south of I-40 as influence of the upper-level low will depart into
the central and high plains Friday. Calm weather is expected
behind the front where subsidence will be dominant. Going into the
evening and overnight hours, a new upper low will develop over
the Big Bend region and deepen as it lifts north towards the
Panhandles this weekend. Rain or storms could be possible along
and south of the stalled front Friday night where some instability
and high moisture content (anomalously high PWATs >1.00") may
provide adequate fuel for development. There is still doubt
amongst models on position of the boundary, as well as timing of
rain/storm initiation. Per usual, the 12z NAM is the aggressor in
terms of initiating more robust convection late Friday night, with
forecast soundings hinting at an environment favorable for
marginally severe hail and wind in our far south/southeast. Right
now current thinking is for most development (especially any
potentially severe convection) to occur south of our area and to
hold off until late Friday night into Saturday when better
dynamics from the low will be closer to our area. With that said,
the southern half of the TX Panhandle will have a decent chance
(30-50% POPs) for rain to start at the end of the short term
period after 06z.
Harrel
&&
.LONG TERM ...
(Saturday through next Wednesday)
Issued at 229 PM CDT Thu May 11 2023
A strange upper level pattern for this time of year has the
potential to bring several days of rain chances from Saturday
through next Wednesday.
A broad upper level trough will be generally stationary across the
western U.S. under high pressure over southwest Canada through
Sunday. Several upper level short wave troughs are expected to move
across the Panhandles Saturday and Sunday on the eastern edge of the
main upper level trough. These disturbances will couple with plenty
of low level moisture to bring rounds of showers and thunderstorms
to the Panhandles this weekend. At this point, the best chance at
seeing the heaviest rain looks to be across the south-central and
southeast Texas Panhandle. This is where the best dynamics will
pass over. If thunderstorms can become robust on Saturday, they may
pose a flooding threat given the large scale lift and light winds
aloft across the south-central and southeast Texas Panhandle.
The center of an upper level high initially over the southeast U.S.
will build back to the west and it will set up shop over the
southern Rockies by late in the day on Monday. Moisture trapped
under this high should continue to be abundant, so showers and
thunderstorms continue to look likely even as the high builds back
to the west.
The upper level flow will then become northwesterly for Tuesday and
Wednesday which will help to bring any mountain convection this way.
High temperatures Saturday through next Wednesday look to be below
normal with readings generally in the 60`s and 70`s.
&&
.AVIATION...
(00Z TAFS)
Issued at 817 PM CDT Thu May 11 2023
For the 00Z TAFs, winds will diminish this evening. A cold front
will move across the region this evening and tonight with north
winds in its wake. Overall, VFR conditions are forecast to prevail
at KGUY, KDHT, and KAMA through late Friday afternoon.
02
&&
.PRELIMINARY POINT TEMPS/POPS...
Amarillo TX 51 86 54 69 / 0 0 30 70
Beaver OK 52 84 52 77 / 10 0 10 30
Boise City OK 46 76 47 71 / 0 10 10 30
Borger TX 53 88 56 76 / 0 0 20 60
Boys Ranch TX 50 86 54 72 / 0 0 20 60
Canyon TX 50 86 53 67 / 0 0 40 80
Clarendon TX 54 87 57 69 / 0 0 40 80
Dalhart TX 46 80 49 71 / 0 0 20 50
Guymon OK 50 81 50 76 / 0 0 10 30
Hereford TX 50 87 53 67 / 0 0 40 80
Lipscomb TX 51 87 53 76 / 0 0 20 40
Pampa TX 52 86 54 72 / 0 0 30 70
Shamrock TX 54 88 57 72 / 0 0 40 80
Wellington TX 54 90 58 72 / 0 0 50 90
&&
.AMA WATCHES/WARNINGS/ADVISORIES...
TX...None.
OK...None.
&&
$$
SHORT TERM...38
LONG TERM....89
AVIATION...02
AREA FORECAST DISCUSSION
National Weather Service Bismarck ND
1032 PM CDT Thu May 11 2023
.UPDATE...
Issued at 1030 PM CDT Thu May 11 2023
Changes at this update mainly based on radar trends. Showers with
a few thunderstorms continues to be found across western and
central portions. CAPE is starting to diminish while shear also
remains modest but not fully aligned with the higher amounts of MU
CAPE. Lapse rates are also not quite as steep with the setting
sun. Overall the threat for severe weather tonight is rapidly
diminishing. Decided to make one HWO segment for tonight for the
mention of lightning and sub severe thunderstorms. Other change is
to lower PoPs for southeastern portions of the CWA. Here it looks
like dry air aloft will inhibit chances for rain tonight and
quite possibly through Friday morning. Perhaps some of these areas
without rain may see some patchy fog tonight, although confidence
was not high enough to include at this time. Otherwise forecast
remains mainly on track.
UPDATE Issued at 645 PM CDT Thu May 11 2023
Overall minor updates made to adjust for ongoing radar trends of
precipitation mainly along and west of Highway 83 at this moment.
Marginal risk for severe thunderstorms remains across much of the
central and southwest portions of the CWA. Current mesoanalysis is
showing a pocket of weak to modest ML CAPE in these ares. Shear is
better than last night, although is not quite aligned with the
best instability. DCAPE is also fairly low at this time. A few
thunderstorms are starting to develop in these areas, although it
does seem evident parameters are just not aligning up at this
time. That being said cannot rule out an isolated stronger storm
through the evening, especially in south central portions. Hail
will be the main threat with any storms, with perhaps some gusty
and erratic winds as well. Otherwise forecast overall remains on
track for a showery night and day tomorrow. Winds may be breezy at
times. Low temperatures tonight look to generally be in the 50s.
&&
.SHORT TERM...(This Evening through Friday)
Issued at 339 PM CDT Thu May 11 2023
Increased precipitation and colder weather is expected through the
short term.
An upper low over eastern Colorado continues to move northeastward
toward the Northern Plains. Widespread divergence aloft has lead
to synoptic scale lift across the Dakotas. Multiple impulses are
forecast to move across the jetstream this afternoon and tonight.
Deep warm advection spanning over a stationary boundary over
western North Dakota is causing a precipitation axis spanning from
western into south central North Dakota. Thunderstorms and
showers are going to expand across the west this evening as the
upper low continues to draw closer. There is a chance for
isolated severe thunderstorms across southern half of the state,
but the window for severe weather remains short. Effective bulk
shear around 20 to 30 kts is present across the southwest, but the
RAP moves much of the shear ahead of the precipitation this
evening. MUCAPE around 1000 j/kg will also be a limiting factor
for severe weather as instability is a bit on the weaker side.
A surface low over western South Dakota is forecast to move up
into western North Dakota tonight leading to heavy rain. Heavy
rain is going to lead to high probabilities around 80% for 1 inch
or more of rain. Probabilities begin to drop for 2 inches or
more of rain. Precipitation increases tonight through tomorrow as
a stronger impulse moves through the Northern Plains.
Temperatures tomorrow will remain in the 60s, below normal, due
to precipitation. Gusty winds will be observed across the state
through the short term.
.LONG TERM...(Friday Night through Thursday)
Issued at 339 PM CDT Thu May 11 2023
Warmer and drier weather is expected through the long term.
Precipitation will begin to ramp down Saturday as an upper low
retrogrades across Western CONUS. A col causing synoptic scale
divergence could keep lingering showers into Sunday morning. Skies
will begin to clear out Sunday afternoon as surface high pressure
moves into the state. More of the mundane weather pattern will
set up next week. A large ridge across Alberta will slowly move
eastward resulting in eastern edge of a low thermal ridge spanning
into eastern Montana. Temperatures will begin to warm up by the
middle of next week into the 70s and 80s. The warmer drier weather
will linger through most of next week. By the end of next week
there could be increased chances for precipitation as a wave moves
in from the northwest.
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday Evening)
Issued at 645 PM CDT Thu May 11 2023
Showers and thunderstorms will bring MVFR to perhaps brief IFR
conditions through much of the forecast, with perhaps some VFR
conditions in between showers. This evening showers and
thunderstorms look to be mainly along and west of a line from KBIS
to KMOT. Here MVFR conditions are expected, although VFR
conditions may be found when there is not any rain. East of this
line looks to be mainly VFR this evening. Tonight into Friday,
lower clouds increase in coverage across the area. This could
bring widespread MVFR to IFR conditions. Rain showers with perhaps
some thunderstorms will also be possible at times for most TAF
sites. Some breezy north to northeast winds may also be found for
Friday.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
UPDATE...Anglin
SHORT TERM...Johnson
LONG TERM...Johnson
AVIATION...Anglin
Area Forecast Discussion
National Weather Service Grand Rapids MI
810 PM EDT Thu May 11 2023
LATEST UPDATE...
Aviation
.DISCUSSION...(This evening through next Thursday)
Issued at 345 PM EDT Thu May 11 2023
--Showers Friday, Mainly South--
Weakening/shearing shortwave comes into srn lwr MI on Friday
afternoon and evening, with abrupt jump in PWATs from around 0.5
inches to over 1.5 inches. Any showers on the leading edge of the
PWAT gradient may struggle to reach the ground initially due to
lingering dry air below 10K ft. However once the higher PWATs
arrive that will support deeper/locally heavier showers and the
rain should have no problem at all reaching the ground.
Swaths/areas of over a quarter to perhaps one half inch of QPF
are likely before the rain diminishes Friday night, mainly south
of I-96. It is worth noting that there is still some ensemble
support for locally up to two inches of rain near the I-94
corridor, and the latest deterministic RAP shows these excessive
amounts as well. This is an unlikely scenario but is supported by
the high PWAT values that the srn stream shortwave currently over
MO sends in our direction Friday. Rain probabilities Friday
decrease substantially north of I-96 and especially north of M-20.
Sfc based convection seems unlikely Friday afternoon if the sfc
dew points do not come up appreciably. NAM dewpoints near 60 are
probably overdone with no good inflow from the south expected and
the sfc winds remaining light southeasterly. However dry subcloud
air may support some briefly gusty winds in any heavier rain
showers that do occur.
--Dry/Warm Saturday, Cooler with Low Chance of Showers Sunday--
Renewed shortwave ridging in the wake of Friday`s shortwave and a
new push of drier air from the northeast supports a mainly dry
day on Saturday. Highs will depend on the degree of mid and high
level clouds, but at least partly sunny skies should send highs
into the upper 70s.
On Sunday it looks we will see considerable clouds from upstream
convection well west of MI, and some of the remnant showers from
that convection could be sliding into srn lwr MI in the afternoon
in a decaying mode. Also a shortwave is progged to slide in from
the north later in the day. Temps will be held down Sunday due to
the clouds and arrival of cooler air in the low levels from the
northeast. Highs may struggle to reach 70.
Another stretch of dry/pleasant weather is expected for much of
next week as sfc ridging and dry air dominates again.
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 752 PM EDT Thu May 11 2023
The dry atmosphere will start to moisten up on Friday as a low
pressure system approaches from the south. By the afternoon, there
may be some rain falling out of a VFR cloud deck. Toward 00z
Saturday, the low level lift increases. This may result in a MVFR
cloud deck which may start to lift in from Indiana. They would
impact KAZO and KBTL first. The pressure gradient remains weak so
any winds will be mostly under 10 knots. Slight instability is
forecast over far southern lower Michigan later Friday, mainly
after 22z, but the confidence for an isolated storm is too low to
include it in the forecast at this time.
&&
.MARINE...
Issued at 345 PM EDT Thu May 11 2023
Light winds continuing on Lk MI into Friday before moderate
northeast flow of 10-20 kts develops for the weekend. This may
support locally rough conditions up near Big Sable Point, but no
marine advisories are anticipated at this time.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...None.
LM...None.
&&
$$
DISCUSSION...Meade
AVIATION...MJS
MARINE...Meade