Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 09/25/21
Area Forecast Discussion
National Weather Service Des Moines IA
642 PM CDT Fri Sep 24 2021
...Aviation Update...
.DISCUSSION.../Tonight through Friday/
Issued at 215 PM CDT Fri Sep 24 2021
Key Points
- Showers and gusty winds through the rest of the afternoon
associated with cold front currently moving through.
- Well above normal temps next week possibly pushing daily
records. See climate section for forecast/record info.
A cold front is sweeping across the state this afternoon bringing
gusty northwest winds, some showers, and cooler temps. Highest
northwesterly wind gusts are occurring immediately behind the
frontal boundary where the strongest caa and pressure rises
reside. An hour or so of 30+ kt gusts have been common before
subsiding a bit. Radar returns show scattered to widespread
showers also moving through as kinematic ascent associated with a
shortwave aloft overspreads the frontal zone. Precip trends and
wind gusts have been a chase for much of the day as hi-res models
have struggled to handle the sub-cloud dry layer. A fair share of
the rain on radar has not made it to the ground today. RAP
mesoanalysis has also shown little to no MUCAPE through the day,
however the bubbly appearance of clouds on visible satellite and
some detected lightning strikes suggests instability may be a bit
more robust than models believe. Thus included mention of thunder
in the forecast through the rest of the afternoon, mainly over the
southern half of the area. A large area of synoptic subsidence is
evident on satellite moving across the Dakotas into Minnesota.
This will slide over the forecast area tonight in concert with a
surface high dropping through the region. Expect another night of
cool temperatures as wind relax under clearing skies, providing
ideal conditions for efficient radiational cooling. Some lows in
the mid to upper 30s may occur again in parts of western and
northern Iowa. Forecast was trended toward a blend of MAV guidance
and 25th percentile of the NBM to bring lows a few degrees cooler
than previous forecast.
Temperatures warm through the weekend as an upper ridge builds
over the high Plains. High confidence in above average
temperatures through at least the first half of next week as the
upper pattern stalls a bit, leaving 850mb temps near or above 20C
which is above the 95th percentile of NAEFS climo for this time
of year. Monday and Tuesday appear to be the warmest days at this
time and may make a run toward daily record highs, possibly
exceeding 90 degrees in some areas. Upper ridge axis kicks east
toward the middle to latter half of the week as mean troughing is
established out west. Models suggest this will eventually
transition into a closed low over the desert southwest with
southwesterly flow extending into the central conus. Lift and
broad waa associated with weak waves passing through the mean flow
will bring precip chances back to the region. Highest PoPs are
focused over western Iowa which will be near the vicinity of an
inverted surface trough stretched sw-ne over the Plains. Still
quite a bit of uncertainty though considering the probable rain
resides in the Day 6-7 range and the potential for stubborn dry
air to eat into the easterly progression of any rainfall.
&&
.AVIATION.../For the 00Z TAFS through 00Z Saturday evening/
Issued at 638 PM CDT Fri Sep 24 2021
With gusty NW winds and scattered showers easing behind the
frontal passage earlier today, VFR conditions are expected to
prevail throughout this TAF period. Winds will settle westerly
overnight and may gust to around 20kts at times.
&&
.CLIMATE...
Issued at 130 PM CDT Fri Sep 24 2021
Forecast record highs for early next week....
Monday Tuesday Wednesday
Des Moines Forecast: 89 Forecast: 91 Forecast: 87
Record: 91 (1956) Record: 99 (1953) Record: 90 (2002)
...................................................................
Waterloo Forecast: 87 Forecast: 88 Forecast: 87
Record: 89 (1954) Record: 91 (1953) Record: 90 (1953)
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
DISCUSSION...Martin
AVIATION...Curtis
CLIMATE...Martin
Area Forecast Discussion
National Weather Service Austin/San Antonio TX
654 PM CDT Fri Sep 24 2021
.AVIATION...
Surface high pressure will continue to move east over the next 24
hours, resulting in a change in wind direction to east-southeast, and
the resumption of more humid Gulf air into the area. CAVU expected
tonight, with maybe a FEW015 around sunrise. Winds will be light and
variable overnight, then pick around 7-9KT after 15Z. KDRT will have
a slightly higher mean wind and gusty at 10G20KT Saturday afternoon.
&&
.PREV DISCUSSION... /ISSUED 252 PM CDT Fri Sep 24 2021/
SHORT TERM (Tonight through Saturday Night)...
As we wrap up another week we`ll take all the thank-you`s we can get
from the south-central Texans enjoying this absolutely beautiful
weather! RAP analysis depicts weak ridging aloft overhead today
while surface high pressure is centered well off to our east across
the SE CONUS. This ridging is progged to gradually strengthen
through the short term. Weak southeasterly surface flow will
continue with winds below 10mph today except across portions of the
Edwards Plateau. There, RH will fall into the upper teens and lower
20s this afternoon, and briefly elevated fire weather conditions may
result. Tomorrow will be a repeat performance in this area, mainly
west of a line from Rocksprings to Eagle Pass. Otherwise, quiet and
mostly clear today through tomorrow with moderate diurnal swings in
temperature as gulf moisture is mostly held at bay for another
couple of days. Lows will be mainly in the mid 50s to mid 60s the
next two mornings while daytime highs today and tomorrow top out in
the mid 80s to low 90s.
LONG TERM (Sunday through Friday)...
An upper low is expected to be located over the northern Baja
peninsula on Sunday. In advance of this low, a tap of mid and upper
level Pacific moisture will begin working in from the west. We will
see some moisture from the Gulf begin to move back into the region on
Sunday. However, the moisture will initially be shallow and we should
manage to see efficient mixing and lowering of afternoon dewpoints
into the 50s across all areas, except the coastal plains. Gulf
moisture return really begins to ramp-up Sunday night into Monday
morning with dewpoints back to feeling more like summer. The above
mentioned upper low will gradually move eastward and some subtle lift
could gin up a few afternoon showers and storms along and east of
I-35/I-37 and across far western Val Verde county. As the upper low
begins to open and eject northeastward on Tuesday, a subtropical jet
on the southern edge of this low will begin to move in from the west.
There is some disagreement on the location of this jet, but our
region is expected to remain in the favored left exit region of the
upper jet. In addition, the increase in mid-level shortwave activity
and plenty of moisture, should yield scattered showers and storms on
Tuesday and Wednesday. Current model data continues to show the
possibility of some locally heavy rain possible late Tuesday into
early Wednesday as the upper jet axis moves overhead. It will be
difficult to pinpoint where this will occur, but given the stronger
lift to our northwest, this would tend to favor areas along and west
of the I-35 corridor.
The active pattern looks to remain intact as we head into the latter
portion of the upcoming work week. The medium range models show
another deep upper system moving into the northern Baja/desert
southwest while the subtropical high remains over the western Gulf of
Mexico. This will keep our region in weak southwest flow aloft
resulting in daily rain chances continuing for Thursday and Friday.
High temperatures through the forecast period should remain at or
just above normal with overnight lows a good 3 to 5 degrees above
normal.
&&
.PRELIMINARY POINT TEMPS/POPS...
Austin Camp Mabry 61 89 62 90 67 / 0 0 0 0 0
Austin Bergstrom Intl Airport 58 89 59 90 66 / 0 0 0 0 0
New Braunfels Muni Airport 59 90 60 91 67 / 0 0 0 0 0
Burnet Muni Airport 59 87 60 88 66 / 0 0 0 0 0
Del Rio Intl Airport 63 90 64 91 68 / 0 0 0 0 0
Georgetown Muni Airport 59 90 60 90 65 / 0 0 0 0 0
Hondo Muni Airport 60 89 60 91 67 / 0 0 0 0 0
San Marcos Muni Airport 59 90 59 90 66 / 0 0 0 0 0
La Grange - Fayette Regional 59 90 61 91 69 / 0 0 0 0 0
San Antonio Intl Airport 62 88 62 89 69 / 0 0 0 0 0
Stinson Muni Airport 62 91 63 92 70 / 0 0 0 0 0
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
Short-Term/Aviation...Zeitler
Long-Term...09
Area Forecast Discussion
National Weather Service Gray ME
952 PM EDT Fri Sep 24 2021
.SYNOPSIS...
Slow moving cold front will produce some heavy rainfall and
embedded thunderstorms tonight into Saturday morning. Another
round of heavy showers Sunday afternoon, especially over the
mid-coast ans central Maine. More seasonal temperatures and the
threat of showers in the mountains are expected for Monday and
Tuesday,
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
Update...
Showers will continue to slowly exit to the east late this
evening in good agreement with the latest HRRR. Radar derived
rainfall rates have come down somewhat since earlier this
evening. Will continue to monitor the Midcoast for a band of
potentially locally heavy rain entering the region from Cape
Cod and the Gulf of Maine as this area will continue to have
deep moisture and high precipitable water values.
Made minor adjustments to temperatures, dew points and winds
this hour as drier air continues to pour in from the west. Will
add more fog over New Hampshire where visibilities are lowered.
Prev Disc...
Cold front is progressing through the area. To the west, across
NH the clearing skies are approaching. Meanwhile through Maine
southerly flow will continue with showers. Low level instability
remains, and some weak rotation has been observed in the
convective line. Some reports of up to 2 inches of rain within
the convective line.
Expect the front to continue to cross the region overnight. Overall
the coverage of showers has been decreasing through the day but the
HRRR continues to suggest that some re development. through
the mountains is possible over the next few hours. This is
supported by the mesoanalysis which shows the higher shear and
CAPE holding on through this area, thus have kept the thunder in
the forecast through the northern part of the area through
midnight.
Tonight the western portion of the CWA should clear out enough for
valley fog formation, and have added this to the forecast. Meanwhile
across the eastern portion of the area, the front will stall keeping
the scattered showers in place across the eastern portion of the
area.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH SUNDAY/...
For Sunday, expect additional rainfall, especially over the
eastern portion of the CWA. There are two separate features
impacting the amount of rainfall. First, a weak wave rotating
around the main low pressure aloft will push into the region.
The more negative tilt this can archive the greater the
precipitation. Secondly, low pressure along the eastern
seaboard will move northwards on Sunday, pushing additional
moisture into the stalled frontal boundary. These two factors
will combine to lead to widespread rainfall across especially
eastern Maine. With two feature competing the confidence in the
placement and precip maxima still remains fairly low. Have kept
total QPF fairly conservative, although certainly the upslope
flow does give a potential for higher totals. This time the
center of the rain will be on the upper Kennebec basin, which
has been plagued by drought.
&&
.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
Warm ridging at 500 MB will be replace by cooler and more seasonable
troughing over the NE CONUS next week, as double omega block
settles across NOAM and the Atlantic, with central trough right
overhead. This low will holds in place thru at least the middle of
next week, when models diverge on solutions.
Starting Sunday sun night should see any showers associated with the
slow moving front exiting to the NE in the evening. This will be
followed by clearing in the south, but clouds linger in the N as the
closed upper low wobbles around over N Quebec. Lows Sunday night
will be in the low-mid 40s in the mtns, to the low 50s in the S.
Mon-Tue will be similar, as 500 MB closed low hangs out to the N, a
and waves of energy move around that low. This will produce some
rounds of clouds, and the chance of showers, mainly in the mtns.
Highs will be in the low-mid 60s in the N to around 70 in the S,
which is still on the high side of normal, and overnight lows 40-45
in the mtns to the low 50s in the S. Skies will vary from partly to
mostly cloudy through the period with more clouds in the mtns.
Confidence drops off a bit Wed-Fri, with models suggesting that
another closed low breaks off on the one to out n and heads
equatorward toward the SE CONUS, with some ridging developing
between the two systems as the pull away from each other. Currently
this would call for a mainly dry and seasonable period, but, again
confidence remains low for mid-late next week.
&&
.AVIATION /02Z SATURDAY THROUGH WEDNESDAY/...
Short Term...Cold front is moving through the area, with MVFR
ceilings currently across NH and VFR and clearing to the west.
This clearing line will move eastwards overnight. Across Maine
pockets of IFR and widespread MVFR will continue until he front
clears the area late. Valley fog may bring IFR to the west in
the morning on Saturday before conditions improve to VFR for
the day.
Long Term...Any flight restrictions early Sunday evening,
should clear out overnight, except for lingering MVFR cigs at
KHIE. Will be mainly VFR Monday through Wed, but again could see
some periods of MVFR cigs at KHIE as flow from the NW persists.
&&
.MARINE...
Short Term...Gusty southerly flow and 5ft seas will keep a SCA
in place across the region through evening. By tomorrow morning,
winds and seas will subside and conditions will remain below SCA
through the weekend.
Long Term...Winds/seas expected to stay below SCA criteria Mon-
Wed.
&&
.HYDROLOGY...
Heavy rain showers will continue through this evening with the
potential threat for flooding along the Midcoast region of Maine.
The threat for flooding does increase on Sunday through the
upper Andro and Upper Kennebec basins where the focus of the
heaviest rainfall exists. 6hr RFC guidance suggests that 2-3
inches in 6 hrs would be enough to push the rivers to flood
stage but suspect the Sunday rainfall will be over a longer
period than that. Thus while flooding cannot be ruled out feel
the most likely scenario is a beneficial rain to the northern
portion of the area.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...None.
NH...None.
MARINE...Small Craft Advisory until 8 AM EDT Saturday for ANZ150>154.
&&
$$
Cannon
Area Forecast Discussion
National Weather Service Marquette MI
809 PM EDT Fri Sep 24 2021
.SHORT TERM...(This evening through Saturday)
Issued at 312 PM EDT FRI SEP 24 2021
GOES Imagery and RAP analysis show well a downstream upper level low
that`s continued to lift northward toward James Bay through the day.
Behind this and present over much of the UP for most of the day so
far, has been weak ridging. This has allow for mostly clear skies
and highs to climb into the 60s and 70s. Upstream, an upper level
low dipping southeast through Saskatchewan is pulling a shortwave
through Minnesota. At the surface, a cold has moved into western
Lake Superior and cloud cover out ahead has moved into the western
UP.
As the upper level low/trough takes on a negative tilt, it will
continue pulling this cold front from west to east through the
region this afternoon and tonight. In response to increasing upper
level divergence, surface cyclogensis is expected along the boundary
near the WI/MI stateline. The results will be increasing low-mid
level fgen that`ll result in a half inch to an inch of rain over the
central UP. Elsewhere, amounts near a quarter to half inch are
expected tonight. Expect skies to clear out soon after the front.
This should allow lows to dip to near 40 in the west. In the east
where the front will be a little slower to exit, expect lows to drop
into the 40s east; the Lake Superior will help moderate temps by the
northern lakeshores, so lows should bottom out near 50F.
Behind the cold front, CAA will bring 850mb temps down to ~1 to 3C
over the region. This, coincident with the warm lake and another
trough rotating around the upper level low will support additional
shower activity Saturday downwind of Lake Superior. Additionally,
the steeper lapse rates that develop in response to the CAA will
allow for some breezier winds near 25 mph, especially near Lake
Superior and Keweenaw. There some 30 mph gusts could be possible.
Daytime highs should climb into the upper 50s to near 60.
.LONG TERM...(Saturday night through Friday)
Issued at 321 PM EDT FRI SEP 24 2021
Saturday night, a closed upper low will be centered between Lake
Superior and James Bay. A secondary vort lobe rotating around the
ULL will drop southeastward across the U.P. overnight and kick off a
few showers, especially over the Keweenaw and eastern U.P. A warming
trend will begin on Sunday, but there could be another round of
scattered showers Sunday morning with low- to mid-level Q-vector
convergence overspreading the area associated with the WAA aloft. As
for temps on Sunday, they will depend on the wind direction which in
turns depends on whether or not a weak surface trough associated
with the ULL to the north reaches the area. If it makes it this far
south, then a cooler northerly wind with onshore flow from Lake
Superior will develop in the afternoon and keep highs down in the
low 60s, as in the NAM. If that trough washes out before it reaches
the area and the flow remains westerly, then highs would make it into
the mid to upper 60s. Opted to not go too far either direction and
keep highs mostly in the mid 60s with this forecast, warmer near the
Wisconsin state line and cooler east. Highs will be similar on
Monday as skies clear with the approach of high pressure from the
northwest.
After Monday, the story still looks like it will be the anomalously
strong ridge building over the Northern Plains and then shifting
eastward into the Great Lakes. Ensemble clusters show only minor
differences in the speed/placement of the ridge and virtually no
variability in its strength. By Wednesday and Thursday, the lion`s
share of the 00z EPS members` 850 mb temps are in the 15-19 C range
which puts the EPS mean between the 90th and 97th percentile of
climatology. Comparing that to the observed highs at IMT for 9/29
(chosen because of its long period of record and it not directly
influenced by the lakes) that would translate to highs between 76
(90th percentile of climo) and 83 (97th percentile). Therefore,
increased high temps Wednesday and Thursday into the mid to upper
70s for most. Would not be at all surprised to see some areas get
back into the low 80s this week given the projected strength of the
ridge. That warmth looks to continue right through Friday. By
Saturday, there is an indication that a short wave rippling through
the flow will begin to knock the ridge down and lead to a slight
cooling trend.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 738 PM EDT FRI SEP 24 2021
A cold front is moving through the region early this evening. The
front has already cleared KIWD and KCMX and the steady rain has
cleared KIWD. Rain will progress west to east and could reduce
visibilities at KCMX and KSAW this evening. Expect ceilings to
decrease to MVFR at KCMX and KSAW with the heavier rain behind the
frontal passage and then improve to VFR overnight. Northwest
winds are also expected to increase behind the front, especially
at KCMX where gusts could approach 30kts. Expect west-northwest
winds to diminish overnight and then become gusty again on
Saturday. Some isolated to scattered lake effect showers will
linger over northern sections of the U.P. on Saturday and could
impact KCMX at times.
&&
.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 312 PM EDT FRI SEP 24 2021
Cold front will move through Lake Superior from west to east this
afternoon through tonight. Ahead of the front, southerly winds near
20 kts are expected. As the system moves through, an area of low
pressure is expected to develop along the boundary and lift
northeast. On the backside of this system, northwest winds are
expected to increase in response to the developing surface cyclone.
I maintained the gale warning over the eastern half of the lake
given the likelihood of gale force gusts to 40 kts. As the parent
upper level low progresses slowly eastward just north of the lake,
another shortwave and shot of colder air aloft will move over the
warmer lake. This will support westerly to northwesterly winds
increasing Saturday across the lake to 20 to 30 knots by afternoon,
and 30 to 35 knots with some gale force gusts possible by Saturday
evening. Expecting winds to diminish Saturday night as ridging
builds in. This ridge will support winds of 20 knots or less through
at least the middle of next week.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
Gale Warning from 2 AM to 6 AM EDT Saturday for LSZ251-267.
Gale Warning from 11 PM this evening to 5 AM EDT Saturday for
LSZ249-250-266.
Lake Michigan...
None.
&&
$$
SHORT TERM...JP
LONG TERM...RJC
AVIATION...Voss
MARINE...JP
Area Forecast Discussion
National Weather Service Spokane WA
221 PM PDT Fri Sep 24 2021
.SYNOPSIS...
Expect warm and dry fall weather this weekend with afternoon
temperatures in the 70s. Saturday will be the warmest day with
more sunshine. Winds pickup out of the southwest Saturday
afternoon and become gusty Sunday afternoon. Chances for rain
gradually increase late Sunday into Monday with a slow moving
cold front. Cooler, showery and breezy weather prevails for the
much of the work week.
&&
.DISCUSSION...
Tonight through Sunday night: High pressure remains over the
Inland Northwest overnight through Saturday. The remains of a
weak disturbance will pass across the region with a band of high
clouds tonight. This along with a light southerly low level winds
will help overnight temperatures not dip as cool as the last
several nights and chances of patchy valley fog look limited.
Skies gradually clear Saturday morning with plenty of sunshine by
the afternoon with temperatures topping out in the mid 70s to
around 80. This is unseasonably warm for the end of September and
the warmest day for the upcoming week and beyond. Winds pick up
out of the southwest Saturday afternoon and evening as the surface
pressure trough skips east of the Cascades. Anticipate local
gusts around 15 mph from the Okanogan Valley to the Palouse.
Under southwest flow aloft, a Pacific upper level trough
approaches the region with a slow moving cold front. Will see
cloud cover and moisture push east of the Cascades Saturday night
through Sunday. In fact, the HRRR smoke model shows a return of
elevated smoke and haze from the CA fires drifting into the
southeast Washington and parts of the Idaho Panhandle. Prefrontal
southwest winds will steadily increase and become gusty Sunday
afternoon and evening with sustained winds of 10 to 20 mph and
gusts 20 to 30 mph, especially from the lee of the Cascades
across the Columbia Basin to the Palouse. It will remain dry in
most areas with considerable high cloudiness for Sunday. The
Cascade crest have the better chance for a light wetting rain.
Temperatures will experience a slight cooling of 3-6 degrees.
Precipitable waters increase above a half inch to near an inch as
the cold front finally pushes into eastern Washington Sunday night
with a band of light rain. The best chance for measurable rain
will be from the Cascade crest to the northern mountains, mere
sprinkles are likely across the Columbia Basin. /rfox
Monday through Friday: A deep low off the central BC coast will
send a cold front across the region late Monday into Monday night.
The strength of the wave combined with a 130-140 kt upper jet
paralling the front should give most locations some rain, with
the Cascade crest, SE Washington, and the ID Panhandle having the
best potential for wetting rains. Some of the ECMWF and GFS
Ensemble members have as much as 0.50-0.75 inches with the mean
around 0.25-0.50 inches. Over Central and northeast Washington
there is greater uncertainty in amounts with potential rain
shadowing off the Cascades especially from the Moses Lake area up
into the Okanogan Valley. Cool and showery weather is expected
behind the cold front on Tuesday with snow levels in the morning
as low as 5500 feet in the Cascades which includes the summit of
Washington Pass. High temperatures are only forecast to reach the
mid 50s to mid 60s which is about 10 degrees below normal. A
short wave ridge should bring drier weather on Wednesday with
patchy valley fog in the morning. Another system pushes in on
Thursday into Friday bringing a chance of rain to the region. Some
moderation of temperatures is likely as the flow turns
southwesterly, but this could be offset by cloud cover and areas
of rain. JW
&&
.AVIATION...
00Z TAFS: High pressure remains over the region through the
period, giving way to light north to easterly winds overnight. A
weak disturbance will bring a band of high cirrus across the
region during the night and exiting Saturday morning. Any patchy
fog will be very limited early Saturday morning in the valleys of
northeast Washington and north Idaho. VFR conditions are expected.
Winds switch to the south/southwest Saturday afternoon with
local gusts 10-15kt. /rfox
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 48 80 53 77 53 71 / 0 0 0 0 20 30
Coeur d`Alene 48 79 52 76 51 70 / 0 0 0 0 20 30
Pullman 45 79 50 75 47 71 / 0 0 0 0 10 20
Lewiston 53 87 58 83 56 77 / 0 0 0 0 10 20
Colville 41 80 45 75 44 66 / 0 0 0 0 20 50
Sandpoint 44 75 47 72 47 64 / 0 0 0 0 20 50
Kellogg 54 78 57 75 53 68 / 0 0 0 0 10 20
Moses Lake 47 82 51 78 54 71 / 0 0 0 0 10 30
Wenatchee 54 83 58 77 58 67 / 0 0 0 10 30 50
Omak 49 84 54 78 54 69 / 0 0 0 10 30 60
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...None.
&&
$$
Area Forecast Discussion
National Weather Service Norman OK
1031 PM CDT Fri Sep 24 2021
...New AVIATION...
.SHORT TERM...
(This evening through Saturday)
Issued at 256 PM CDT Fri Sep 24 2021
Latest observations show the weak surface boundary has reached
the Buffalo mesonet station, which is reporting light
north/northwest winds. This boundary is nearly stationary with a
cold front extending northeast across central Kansas. This front
will progress south, and now anticipated to be somewhat stronger
than previously prog`d. Guidance shows a slight dip in H850
temperatures (by 1-2 degrees), and NBM has trended downward a bit
from past runs. CAMS have trended upwards with wind speeds behind
the front, though this will be short-lived and over a rather
narrow zone behind the boundary.
Interestingly for one day out, there is a 10 degree spread for
tomorrow`s highs among the deterministic models. The NAM is at
the low end and winds are prog`d to be more east/southeast by
tomorrow afternoon. On the other hand, the GFS is the warmest
and winds are, instead, out of the south. The HRRR and RAP both
suggest more of an easterly wind component (similar to the NAM),
and therefore more inclined to agree with the slight reduction in
temperatures. Went ahead and adjusted maxT down slightly towards
CONSSHORT.
Regardless, tomorrow will be a pleasant day outside with sunny
skies and temperatures in the middle to upper 80s. Southern zones
will rise into the low 90s.
Thompson
&&
.LONG TERM...
(Saturday night through next Thursday)
Issued at 300 PM CDT Fri Sep 24 2021
A tightening pressure gradient will lead to an increase in wind
speeds during the day Sunday, especially across western Oklahoma.
The NBM has been running too high on dewpoints the past several
days, and with dry antecedent conditions, dewpoints were lowered
across portions of northwest Oklahoma during the afternoon where
models have been showing a punch of drier air during peak mixing.
This led to an expansion of near-critical fire conditions over our
previous forecast across northwest Oklahoma, with elevated
conditions expected for much of the rest of western/northern
Oklahoma and western north Texas. Some signal is there for high-
level cirrus during the afternoon, which may inhibit mixing some
(with effects on dewpoints and winds) and will need to be watched
for. Otherwise, expect breezy conditions for much of the rest of the
area with highs climbing into the low 90s for most.
By Monday, a cutoff low will begin to approach the area from the
west, eventually opening into an open wave late Tuesday. Models have
come into somewhat better agreement with regards to the overall
synoptic pattern through early next week, but some differences
remain. The GFS/GEFS are faster and bring showers and thunderstorms
into much of the area by Tuesday afternoon, while the ECM is slower
and waits until Wednesday for more widespread precipitation
coverage. For now left the model blend as is, with low chances on
Tuesday (highest across southern Oklahoma and north Texas), and much
higher chances Wednesday and Thursday. By the end of next week model
spread increases as another trough digs into the southwestern US.
Regardless of the details, continued western US troughing and
increasing PWATs point to a continuation of precipitation chances
through the end of next week.
At this time wind shear looks very weak through much of next week,
which will mitigate any organized severe weather concerns. As PWATs
increase toward the middle and end of next week, heavy rainfall and
localized flooding of poor drainage areas may become a concern.
Ware
&&
.AVIATION...
(06Z TAFS)
Issued at 1003 PM CDT Fri Sep 24 2021
VFR conditions are expected through Saturday. A front will shift
winds from south to northeast tonight as it moves southward
through Oklahoma. It will weaken through the day Saturday.
&&
.UPPER AIR...
Issued at 1200 PM CDT Fri Sep 24 2021
No upper air flights are planned at this time.
&&
.PRELIMINARY POINT TEMPS/POPS...
Oklahoma City OK 86 56 87 61 / 0 0 0 0
Hobart OK 88 55 90 60 / 0 0 0 0
Wichita Falls TX 88 55 91 60 / 0 0 0 0
Gage OK 89 53 87 61 / 0 0 0 0
Ponca City OK 88 55 84 60 / 0 0 0 0
Durant OK 86 56 90 60 / 0 0 0 0
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...None.
TX...None.
&&
$$
SHORT TERM...01
LONG TERM....08
AVIATION...09
Area Forecast Discussion
National Weather Service Paducah KY
622 PM CDT Fri Sep 24 2021
.UPDATE...
Issued at 622 PM CDT Fri Sep 24 2021
Update is for the 00 UTC TAF`s. Also, in our public products, we
added some isolated thunder for the late night and early Saturday
morning time frame. We see near to slightly below zero elevated
li`s lifting parcels from h8/h7, along with lapse rates above 6
C/KM. Also see elevated instantaneous Flash Rates in the ECMWF
data, and HRRR lightning density prog data. There may not be too
much to it, but cannot rule it out given the dynamic nature of the
vigorous mid trop s/wv.
&&
.SHORT TERM...(Tonight through Sunday night)
Issued at 233 PM CDT Fri Sep 24 2021
Southwesterly to westerly low level flow will increase late today
and tonight ahead of a cold front, driven by a mid level shortwave
out of central Canada, though surface winds tonight should be
generally light out of the south. The surface front is progged to
enter the northwestern fringes of the PAH forecast area shortly
before daybreak Sat. This feature will result in increasing
cloudiness tonight, especially overnight, and a chance of
measurable rainfall for parts of southern IL, southwestern IN, and
northern parts of the Pennyrile region of KY, mainly between
midnight and mid-morning Fri. Areas north of I-64 will have the
highest PoPs (as high as likely). The wind shift to the north
should be complete by around noon everywhere as skies rapidly
clear from west to east.
In the wake of the front, light and sometimes variable surface
winds are forecast to prevail until Sun, when the pressure
gradient increases again between departing high pressure and low
pressure in the central Plains. This will result in a
southwesterly wind 10-15 mph Sun for us, persisting Sun night,
but settling down to around 5 mph.
Meanwhile, the airmass modification/warmup will continue under
ample daytime sunshine, albeit with a brief pause because of the
cold front. Temps should rebound into the lower 80s nearly
everywhere by Sun afternoon, with lows Sun night in the upper half
of the 50s in general.
.LONG TERM...(Monday through Friday)
Issued at 233 PM CDT Fri Sep 24 2021
Ensemble modeling suggests a warm/dry long term portion of the
forecast, dominated by high pressure throughout the atmospheric
column. CIPS analog data still strongly paints a dry/below normal
pcpn period, and even the experimental CPC output indicates this
could stretch even longer, for a prolonged dry spell perhaps
measured in week(s).
That said, the mid week period does offer a possibility of rainfall,
at least west of the Mississippi, as return flow moisture works
northward from its Lower Valley. It will come down to the strength
of the holding ridge just to its east, and for now, it looks to hold
strong and even backbuilds again, so our accepted blended pops are
minimal, and restricted to the SEMO Ozarks, but still audibly
present.
The dominant high pressure and succeeding days of dry weather will
help temps run several degrees above seasonal norms through the
period, with daily highs in the mid to upper 80s and lows in the
lower 60s.
&&
.AVIATION...
Issued at 622 PM CDT Fri Sep 24 2021
A front will move through later tonight, accompanied by a band of
showers and perhaps isolated thunderstorms, best chances east of
the MS River and especially SE IL, SW IN and NW KY. Cigs will
lower but be mostly VFR with the front. Some reduced visibilities
anticipated, but confidence in precip coverage and intensity is
still lower than average. Skies will clear out from NW to SE
morning to midday Saturday. Winds ahead of the front will be SSW 4
to 8 kts, switching to the N/NW 5 to 10 kts morning to midday
Saturday. Now through 06 UTC, quiet weather with just high clouds.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...None.
MO...None.
IN...None.
KY...None.
&&
$$
UPDATE...08
SHORT TERM...DB
LONG TERM...DH
AVIATION...08
Area Forecast Discussion
National Weather Service Reno NV
128 PM PDT Fri Sep 24 2021
.SYNOPSIS...
Expect warmer temperatures with a return of west winds into the
weekend. Another cold front will bring increasing winds Sunday-
Tuesday and much cooler temperatures by the middle of next week.
Chances for light precipitation return next week, mainly in
northeast California and near the Sierra.
&&
.DISCUSSION...
Warm and dry conditions for the weekend with the current easterly
flow becoming light SW-W late this afternoon and evening. This will
bring the return of smoke and haze to the Sierra and western Nevada
Sierra Front by early this evening, based on latest HRRR Near
Surface Smoke simulations.
After typical afternoon breezes Saturday, a slight uptick in winds
is expected Sunday afternoon, with gusts of 25-35 mph possible. This
brings fire weather concerns Sunday, however, Monday will feature
even stronger winds (gusts 30-45 mph possible) ahead of an
approaching cold front, with continued breezy post-frontal winds
Tuesday. The current frontal timing looks to be late Monday night
into Tuesday morning, with a wind shift from SW-NW behind the front.
Please see the fire weather section below for additional details. In
addition to the fire concerns, expect typical travel and recreation
impacts.
The front will usher in cooler temperatures Tuesday-Wednesday, and
the spread in the guidance continues to shrink. So while there
remains some wiggle room, it does look like high temps about 10
degrees below normal will result. Wednesday morning will feature the
coldest overnight lows and temps could easily drop below freezing in
colder rural and suburban valleys.
Moisture associated with the frontal boundary is limited and the
front itself moves through rather quickly, so liquid totals are
likely to be minimal, generally under a tenth of an inch. Best bet
for measurable rain will be the northern Sierra, northeast
California, and far northern Washoe County, near the Oregon border.
A few spotty, very light, showers are possible elsewhere.
The bulk of the forecast simulations are pointing toward a transient
ridge rebuilding over the west for the end of the week, with a lot
of uncertainty thereafter. Some simulations bring another system
toward the west coast, while others maintain the ridge and keep the
trough in the northern Pacific for the start of October. Forecast
models tend to struggle with transition seasons, and this is no
exception. Check back for the latest. -Dawn
&&
.AVIATION...
Winds will begin to shift from the N/NE flow to a W/SW pattern into
this evening, which could bring smoke and haze into the area from
wildfires ongoing in California. KTVL may have lower visibility
from the Caldor fire, while KMMH could see smoke from the KNP
Complex in the Sequoia National Forest.
Dry conditions dominate the area during the weekend with chances for
increasing W/SW winds Sunday to near 30kts ahead of an approaching
trough. Potential for mountain wave turbulence to increase east of
the Sierra as the trough approaches. HRICH
&&
.FIRE WEATHER...
* Fire Weather Watch has been issued for Monday afternoon and
evening for gusty winds and low humidity in western Nevada,
northeastern California, and the Eastern Sierra.
* Low pressure moves into the Pacific Northwest on Sunday with
increasing winds across the region. Wind gusts up to 25-35 mph
will be possible Sunday afternoon, along with RH values down
near 10%. A couple hours of critical conditions may be possible
on Sunday, but no Red Flag Warning is anticipated at this time
for Sunday.
* By Monday, the low pressure moves into northern CA/NV, with winds
aloft increasing even more, as well as tightening of surface
pressure gradients. Gusts of 30-40 mph are expected for most
valley locations Sunday afternoon with gusts up to 40-50 mph
possible for ridges and in wind prone areas. Latest models show a
dry slot moving into the region on Monday as well, which will
bring humidity down to around 10-15% for areas in western Nevada
and around 15-20% west of US-395 in northeastern California and
the Tahoe Basin. Expect to see anywhere from 3-7 hours of critical
conditions, mainly during the afternoon/early evening hours.
* Gusty winds will continue Monday night into Tuesday morning as
the shortwave swings through the region. The peak ridge winds
look to be early Tuesday morning as the cold front moves
through the region. The ridge areas will not decouple Monday
night and will continue to blow through the night. Depending on
the timing of the front/shortwave, we may have to adjust the
timing of the watch and any subsequent Red Flag Warnings. Winds
shift out of the northwest on Tuesday behind the cold front,
remaining breezy through the day.
-Hoon
&&
.REV Watches/Warnings/Advisories...
NV...Fire Weather Watch from Monday afternoon through Monday evening
NVZ420-421-423-429-458.
CA...Fire Weather Watch from Monday afternoon through Monday evening
CAZ270>272-274-278.
&&
$$
For more information from the National Weather Service visit...
http://weather.gov/reno
For frequently asked questions about the Area Forecast Discussion
visit...
http://weather.gov/saltlakecity/general/afd_faqs.php
Area Forecast Discussion
National Weather Service Tampa Bay Ruskin FL
755 PM EDT Fri Sep 24 2021
.UPDATE...
Dry and stable air above 700mb (or roughly 10k feet) per the 00Z
RAOB at TBW has really suppressed any convective activity north
Hardee county this afternoon as the stalled frontal boundary
remains stretched from approx Naples to West Palm Beach according
to the latest surface analysis. RAP still shows a juicy atmosphere
south of the I-4 corridor with plenty of CAPE and no CINH - hence
the thunderstorms that persist across SWFL this evening. These
are moving rather slow due to the meager steering flow, so expect
some locally heavy rain to be possible as Lee/Charlotte/Highlands
counties have already seen solid rainfall totals this week. No
changes necessary to the current forecast. Have a great weekend!
&&
.AVIATION...
A few storms linger this evening near the KPGD terminal and have
put a brief TEMPO in for them, as well as left VCTS in at the
other southern terminals for the next few hours. Storms should
then clear out for the overnight hours, with winds generally
becoming light ENE. Winds increase from the E/SE and then turn
onshore after 15Z Saturday, with storms returning across the
southern and inland terminals generally after 20z Saturday. VFR
expected, except MVFR to IFR possible in storms.
&&
.MARINE...
Stalled frontal boundary remains stretched across south FL. East
to northeast winds will prevail this weekend, but generally remain
below 10 knots with benign seas expected. Any rain chances should
remain south of Tarpon Springs. A shortwave trough will kick the
front south of the peninsula by the end of the weekend. Overall,
nice boating conditions across the Eastern Gulf of Mexico though
at least the middle of next week.
&&
.Preliminary Point Temps/PoPs...
TPA 75 90 75 89 / 10 20 10 10
FMY 74 90 74 91 / 40 50 30 20
GIF 73 90 71 90 / 20 20 10 10
SRQ 74 89 73 89 / 20 30 20 10
BKV 68 90 68 89 / 10 10 10 10
SPG 77 89 76 89 / 10 20 20 10
&&
Sea Breeze Thunderstorm Regime For Today: Sea Breeze Thunderstorm Regime For Tomorrow:
For Additional Information On Sea Breeze Regimes go to the link below
https://www.weather.gov/tbw/ThunderstormClimatology
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...None.
Gulf waters...None.
&&
$$
UPDATE/MARINE/UPPER AIR...42/Norman
AVIATION/DECISION SUPPORT...24/Hubbard