Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 05/20/23
Area Forecast Discussion
National Weather Service Billings MT
315 PM MDT Fri May 19 2023
.DISCUSSION...
Tonight through Sunday night...
N to NW flow aloft will persist tonight through Sunday. This will
continue to bring patchy smoke into the forecast area from
wildfires in Alberta and Saskatchewan, and the RAP model supported
this idea. Smoke could be seen in visible satellite imagery this
afternoon, as well as on the webcams. KLVM reported visibility of
5SM at 19Z. An AQA was in effect for the forecast area in MT for
moderate air quality. Will issue another SPS for air quality/smoke
for Sheridan County, WY.
Otherwise, upper ridging will bring dry conditions to the forecast
area tonight with mild weather. A shortwave, seen on water vapor
imagery over central Alberta this afternoon, will move SE through
NE MT Saturday afternoon and evening. The wave will push a weak
cold front S through the area in the afternoon. GFS and SREF
showed CAPES of 500-1000 j/kg with little shear. PWAT`s increase
to around 0.75 inches. Focus of convection will be from KBIL W
and over the NE Bighorns with PoPs of 20-40%. Kept convection
chances going through 03Z Sat. night based on deterministic
models, and spread 20 PoPs SE through Big Horn County E into
Powder River County. Convection will dissipate late in the evening
with lack of lift and insolation.
SW flow aloft increases over the area Sunday and Sun. night ahead
of Pacific NW system. CAPE and shear on Sunday will be similar to
the values on Saturday with PWAT`s 0.50-0.75 inches. Chances for
convection will be confined to over and near the mountains mainly
in the afternoon.
It will be warm both days with highs in the 80s which was 15-20
degrees above normal for this time of year. Records were mostly in
the 90s, so not looking at record heat. Arthur
Monday through Friday...
The main focus points over the long term will be ridging keeping
our temperatures above to much above average and prolonged
southwest flow next week bringing multiple precipitation chances.
Monday will be hot with widespread temperatures in the high 80s to
low 90s before a cold front passes through and the ridge axis
moves further east. We will still have anomalously high heights
the rest of the week with temperatures generally in the 70s to low
80s.
Monday will see a Pacific trough located to the west of us
bringing southwest flow favorable for precipitation chances. Winds
will also be southerly throughout the plains allowing Gulf
moisture to be advected into the region bringing high PWAT values.
There will be some instability Monday and Tuesday with poor shear.
There may be some isolated showers and thunderstorms if anything
is able to form. Tuesday night through the rest of the week,
better moisture moves in to create a more moist boundary layer
bringing the better chances for precipitation. The
shear profile may become more favorable but instability looks to
remain along the border with the Dakotas making severe storms
uncertain. Regardless, repeated precipitation chances next week gives
most locations around a 50% chance for 0.25 inches according to
NBM. This pattern change will bring about our best chance at
getting rid of the smoke early next week. Torgerson
&&
.AVIATION...
Another push of heavier smoke is expected tomorrow morning
bringing about reduced visibilities tomorrow, slant-wise
visibility will be especially impacted. Winds look to remain light
and skies remain clear until the possibility of some mid to high
level cloud tomorrow afternoon. Torgerson
&&
.PRELIMINARY POINT TEMP/POPS...
Sat Sun Mon Tue Wed Thu Fri
-----------------------------------------------------------
BIL 050/084 054/085 056/088 056/078 055/072 053/076 055/079
02/T 20/K 02/T 31/B 24/T 45/T 45/T
LVM 049/081 050/083 052/083 049/077 048/069 048/074 049/076
02/K 22/T 14/T 32/T 25/T 46/T 56/T
HDN 045/085 051/085 051/089 055/080 055/075 053/077 054/082
01/K 20/K 02/T 31/B 34/T 45/T 45/T
MLS 044/084 053/085 056/090 060/080 056/075 055/074 055/079
01/K 10/K 00/U 31/U 23/T 43/T 43/T
4BQ 045/082 052/084 054/089 057/080 056/077 055/075 054/081
00/K 10/K 00/U 21/U 23/T 34/T 34/T
BHK 041/080 050/083 052/087 056/080 053/074 053/074 051/079
00/K 10/K 00/U 22/W 23/T 34/T 33/W
SHR 044/080 049/080 049/084 051/075 051/074 049/074 050/078
00/K 11/K 01/U 23/T 35/T 45/T 45/T
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...None.
WY...None.
&&
$$
weather.gov/billings
Area Forecast Discussion
National Weather Service Glasgow MT
857 PM MDT Fri May 19 2023
.DISCUSSION...
Evening Update:
Smoke and haze mainly out to the west and east of the Glasgow
area. Late this afternoon, smoke from the Crooked Creek RX fire
from Petroleum County was visible on satellite imagery. For this
reason, I included an broad area of haze for the CWA. Aside from
that, the remainder of the forecast below remains valid.
-Enriquez
Previous Discussion:
Today through Sunday night:
The haze and smoke are temporarily holding off in central MT
through tonight, before another wave of smoke is expected to move
down into northeast MT from Alberta and western Saskatchewan by
early Saturday evening. This will promote air quality issues, with
low visibilities (as low as 1/2 mile at times) being a detector of
how dense the smoke will be. So far, the RAP model gives
confidence of smoke being over northeast MT through at least
Sunday night. It is possible for smoke to continue on to later
periods.
With the frontal passage tomorrow morning, a slight chance of
showers and thunderstorms is possible in far northeast MT near the
ND border.
Monday through Monday night:
There is moderate confidence (50 percent) of scattered
thunderstorms moving through with a shortwave trough passage.
However, uncertainty remains in the timing and location of these
storms. The warmest day of the season is possible ahead of this
wave, so lapse rates will likely be steep (7.5 to 9 C/km). Current
guidance from the NAM, GFS, and NBM agree on dewpoints being in
the mid 40s on this day, with high DCAPE possible. Overall, this
guidance suggests a few stray severe wind gusts across northeast
MT in the afternoon hours.
Tuesday into Wednesday:
There is low confidence (30 percent) in thunderstorms occurring on
Tuesday afternoon, with little agreement on a solution for storm
mode.
Wednesday night onward:
A shortwave trough is showing up in model trends such as the GFS
ensemble, but the question remains of whether or not this push
will reach northeast MT to bring precipitation to the region.
-Stoinskers
&&
.AVIATION...
LAST UPDATE: 0300Z
FLIGHT CAT: VFR until 21Z, then down to MVFR to IFR in areas of
smoke afterward
DISCUSSION: Any areas of haze are lifted to at least 10 SM for
the terminals. The line for haze continues to thin out, and will
remain this way until Saturday afternoon. A push of smoke from
Saskatchewan is expected by early Saturday evening, bringing
visibility down to 1/2 to 1 mile.
SFC WIND: Southeast at 10 to 15 knots decreasing to 5 to 10
knots. After 18Z, becoming northwest 5 to 10 knots.
-Stoinskers/Enriquez
&&
.GLASGOW WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
weather.gov/glasgow
Area Forecast Discussion
National Weather Service Goodland KS
955 PM MDT Fri May 19 2023
.UPDATE...
Issued at 951 PM MDT Fri May 19 2023
Latest short term guidance is hinting at some isolated patchy fog
to impact portions of northeast Colorado after 06z into sunrise.
based on the latest surface analysis, this looks to occur
along/ahead of the surface ridge axis, which is currently nosing
into northeast Colorado. Will have to monitor in case guidance
shows this potential to shift further east towards the Kansas
border, but for now the best chances look to occur over isolated
western portions of Kit Carson/Cheyenne counties.
&&
.SHORT TERM...(This evening through Sunday Night)
Issued at 242 PM MDT Fri May 19 2023
At the start of the short term period, the latest upper air RAP
analysis displays an upper air low over northern WI and an upper air
ridge over the western CONUS with a weak low embedded within the
ridge over southern WY on Friday afternoon. Current surface
observations report some reduced visibilities mainly in the western
portions of the CWA due to Canadian wildfire smoke with the latest
satellite imagery showing scattered to overcast clouds across the
region. Models show this upper air pattern pretty much staying in
place through the rest of Friday with a westerly upper air flow
over the CWA. At the surface, a surface high looks to move south
from the Northern Plains into NE overnight allowing for cloud
cover to lessen as well as winds to become mostly light and
variable. Dry conditions are expected for the remainder of the day
as well. Models also show some reduced visibilities remaining in
the southwestern quadrant going through the night due to the
lingering smoke. Overnight lows expect to be in the lower to
middle 40s.
On Saturday, forecast guidance shows the upper air low residing over
the CO/WY border with the CWA being barely underneath a subtropical
upper air ridge in the morning. By the evening hours, models
continue to give the CWA a westerly flow going into the night. Dry
conditions are expected for the region throughout Saturday as the
surface high slowly moves eastward during the day along with a
surface trough in CO creating a southerly surface flow for the
CWA. Precipitation chances look to stay south and west of the CWA,
but will monitor in case this changes in future runs though there
is low confidence in this happening at this time. Daytime highs
on Saturday look to range between the lower and upper 70s while
overnight lows are forecasted to be in the middle 40s to lower 50s
range.
Going into Sunday, models show the CWA underneath the area where a
split flow joins together in the morning having an upper air low
over the AZ/NM border and an upper air ridge over the northwestern
CONUS that has an embedded weak low over northern CO in the morning.
A shortwave disturbance then appears over the CWA by the late
afternoon and evening hours. At the surface, chances for showers and
thunderstorms are seen in the afternoon and evening hours
particularly in the CO and KS counties. Best chances look to be
south of I-70 in the evening. While there is a few hundred J/kg of
CAPE seen in forecast model soundings, severe weather is not
anticipated at this time as the environment looks to stay capped.
Current QPF totals look to range between a trace to a few tenths
with areas that see precipitation. Fire weather does not look to be
a concern on Sunday as with the other days in the short term period
due to minimum relative humidity values staying above criteria.
Daytime highs on Sunday range between the lower 70s and lower 80s
followed by overnight lows ranging between the upper 40s and lower
50s.
.LONG TERM...(Monday through Friday)
Issued at 201 PM MDT Fri May 19 2023
For this long-term forecast period, the overall weather pattern will
begin shifting from a split-flow and upper level ridge centered over
the High Plains to more of an amplified western United States trough.
What this will mean for our region is that flow aloft will be from the
southwest, allowing shortwave troughs to move through as they rotated
around the primary longwave trough. This should mean a return to active
weather, and with a dryline in place and return flow from the south, a
return to potentially more substantial severe weather.
For Monday and Tuesday, the High Plains will still be situated within a
split-flow pattern. Typically, this does not bring us higher chances
for precipitation. However, there should be a dryline situated
somewhere along the Colorado border, serving as the surface mechanism
for storms to form on. Instability will be on the rise with southeast
flow bringing in warmer air and a return to the Gulf moisture. That
being said, light winds aloft and the lack of substantial shortwave
trough should mean generally quiet weather. A few storms can`t be
totally ruled out, but significant severe weather or widespread storm
coverage should not be anticipated given this setup.
From Wednesday into Friday, the upper level pattern begins to change
and the southern jet stream takes on a more amplified appearance. This
happens as a trough of low pressure forms over the southwestern United
States. As this happens, southeast flow should persist as a surface
trough forms in lee of the Rockies. Moisture return becomes quite
evident with surface dewpoints in the 50s and 60s forecast, and perhaps
into the mid 60s by Friday. Precipitable water readings should also be
on the rise, reaching the 1.3" mark for parts of the region Friday.
Each day, instability will get a little higher with SB Cape climbing
into the 2000-3000 j/kg range by late week. In addition, with the
southern jet stream amplifying across the area, the wind field
strengthens resulting in larger wind shear, with 0-6 km bulk shear
eventually reaching 25-35 kts. With a dryline ebbing and flowing each
day, anticipate thunderstorm development each afternoon and evening
across the High Plains. Some storms could certainly be severe with the
instability and wind shear anticipated, and with the amount of moisture
present, we also can`t forget the potential for heavy rainfall and
flash flooding. Keep an eye on the forecast towards the end of next
week as it would not be surprising to see several days of severe
weather.
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday evening)
Issued at 456 PM MDT Fri May 19 2023
For KGLD, mainly VFR conditions for the forecast period. There
will be periods of patchy smoke through 13z Saturday, with a
brief reduction to visibility to 6sm at times. Winds, northeast
around 10kts through 03z Saturday, then light/variable. By 13z,
south around 10kts, with gusts to 20kts from 17z onward.
For KMCK, mainly VFR conditions for the forecast period. There
will be periods of patchy smoke through 15z Saturday, with a
brief reduction to visibility to 6sm at times. Winds, northeast
10-20kts through 02z Saturday, then light/variable. By 15z, south
around 10kts.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...JN
SHORT TERM...076
LONG TERM...RRH
AVIATION...JN
Area Forecast Discussion
National Weather Service Grand Rapids MI
1059 PM EDT Fri May 19 2023
LATEST UPDATE...
Update
.UPDATE...
Issued at 1059 PM EDT Fri May 19 2023
Surface visibilities are still being affected by haze from western
fires even at this hour. Visibilities range from 9 miles along the
lakeshore to 3-5 miles towards Lansing and Jackson. RAP model
smoke progs show conditions improving through the night in the
northwest flow behind the cold front. Vertically integrated smoke
however will hang around into Saturday. Low clouds are seen off to
our north and west at this hour and those clouds will advance
into the forecast area through the night. We are expecting a dry
rest of the night from this point as the frontal precipitation in
the southeast is clearing out of the area.
&&
.DISCUSSION...(This evening through next Friday)
Issued at 217 PM EDT Fri May 19 2023
- Isolated thunderstorm risk this afternoon
MU CAPE values from SPC`s Mesoscale Analysis page were under 250
J/kg across the area at this time. The values were climbing as
this system draws in some moisture from the southwest. Projections
through 21z suggest the values will increase to around 500 J/kg
prior to the front pushing east of Jackson. Earlier there had been
a few lightning strikes down in far southern Lake MI, but since
then no storm have been observed. We will maintain a low risk for
thunderstorms for a few more hours in the forecasts.
- Warming trend early next week
Mid level heights rise Sunday into Monday as ridging starts to
move in. Down at 850 mb a southerly flow is shown to set up by
Monday with temperatures at that level climbing to near 13 deg C.
This will support temperatures reaching well into the 70`s with
some 80 degree readings possible. A cold front is shown to drop
down from the north Thursday into Friday but based on the latest
trends that feature will likely stay up in Canada. The 850 mb
temperatures are shown to climb to 14 to 15 deg C Memorial Day
weekend which suggests many locations will see the 80s...supported
by the ensemble max T`s from the ECMWF and CMC, but not by the
GFS.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 832 PM EDT Fri May 19 2023
A cold front has swept to the south and east of the TAF sites as
of 00z with a band of rain associated with it about to move east
of JXN. The remainder of the night will focus on 1) haze reducing
visibilities and 2) the formation of lower ceilings.
As for the haze, it is associated with near surface smoke from
Canadian forest fires per the RAP Smoke model. The haze is
actually forecast to improve through the night a bit from 3-5SM to
6 or 6+ statute miles. Slightly improved conditions are expected
on Saturday, but it will still be around to some extent.
As for the low clouds, a surge of MVFR ceilings will invade the
sky from the north overnight (after 04z). These ceilings will
become widespread and reach maximum expanse between 13z and 15z
Saturday morning. VFR conditions will then return for Saturday
afternoon.
Winds from the northwest at 5 to 15 mph will be common the next 24
hours. Wind gusts towards 20 knots will be possible on Saturday.
&&
.MARINE...
Issued at 217 PM EDT Fri May 19 2023
The combination of cold air advection and a tightening pressure
gradient will lead to hazardous conditions for small craft
developing for parts of the nearshore waters later tonight. The
deeper mixing persists into Saturday afternoon...especially near
and south of Muskegon. We will hoist a small craft advisory for
that region. The winds and waves will decrease considerably by
Sunday.
Webcams show reduced visibilities around Grand Haven and South
Haven. We added that risk to the hazardous weather outlook and
included it in the grids.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...None.
LM...Small Craft Advisory from 4 AM to 5 PM EDT Saturday for
LMZ844>847.
&&
$$
UPDATE...Duke
DISCUSSION...MJS
AVIATION...Duke
MARINE...MJS
Area Forecast Discussion...Updated
National Weather Service Lincoln IL
844 PM CDT Fri May 19 2023
.SYNOPSIS...
Issued at 808 PM CDT Fri May 19 2023
Showers and a few thunderstorms will continue into the evening
southeast of a Bloomington to Jacksonville line...before dry
weather returns across the board overnight. Low temperatures will
range from the middle 40s in the Illinois River Valley to the
middle 50s south of I-70.
&&
.UPDATE...
Issued at 808 PM CDT Fri May 19 2023
Showers and patchy drizzle will persist in the vicinity of the
cold front tonight, ending from north to south as the 500-mb
trough axis sweeps across the region. Temperatures will be coldest
north of I-72 where skies completely clear, radiating things down
into the mid 40s. Otherwise, smoke ought to be with us again
tomorrow as we remain in a northwest flow pattern aloft with deep
boundary layer mixing.
MJA
&&
.SHORT TERM... (Through Late Saturday Night)
Issued at 335 PM CDT Fri May 19 2023
20z/3pm surface analysis shows a cold front settling southward
toward the I-70 corridor. Scattered thunderstorms have formed
immediately along/ahead of the boundary from near Danville
southwestward to Shelbyville. Meanwhile further northwest on the
cool side of the boundary, a band of light to moderate showers has
developed along a Bloomington to Jacksonville line. Based on radar
trends and latest HRRR/RAP forecast, it appears precip chances
will linger into the evening across the southeast two-thirds of
the KILX CWA...with the primary threat for thunder shifting south
of I-70. As the front drops further south toward the Ohio River, a
few showers may linger past midnight along/south of a Robinson to
Flora line...with dry weather expected everywhere before dawn
Saturday. In addition to the showers, area obs/webcams have shown
smoke from Canadian wildfires mixing to the surface behind the
cold front. Visibilities have been reduced to 2-4 miles at times,
so have included patchy smoke in the forecast late this afternoon
into early this evening before it disperses and moves out of the
area after dark. Lows tonight will be considerably cooler than
last night...ranging from the middle 40s in the Illinois River
Valley to the middle 50s south of I-70. Despite cloud cover
departing, RAP data continues to suggest a high/thin overcast of
smoke through the night into Saturday. Highs on Saturday will be
below normal for this time of year in the lower 70s.
Barnes
.LONG TERM... (Sunday through Next Friday)
Issued at 335 PM CDT Fri May 19 2023
Upper pattern dominated by western CONUS ridging and eastern
troughing will break down early next week, resulting in a return
to more zonal flow by Monday. With ample smoke upstream across
ALberta/Saskatchewan and deep-layer northwesterly flow initially
in place, think smoky skies will still be observed on Sunday.
Despite the slight obscuration of the sunshine, rising upper
heights will allow highs to climb into the middle to upper 70s.
After that, the western upper ridge will build eastward. Models
have been consistently showing a blocking pattern forming by the
middle and end of the week...with ridging over the Great
Lakes/Midwest and troughing across the Gulf Coast. This will
ensure the continuation of warm/dry weather through the remainder
of the extended. Temperatures will climb well into the 80s after
Monday.
Barnes
&&
.AVIATION... (For the 00z TAFs through 00z Saturday Evening)
Issued at 624 PM CDT Fri May 19 2023
Showers will continue to diminish this evening at CMI/DEC/SPI as
a cold front sags further south across the state. Clouds will
diminish overnight, though some residual smokiness may reduce
visibility to between 5 and 10 SM through Saturday afternoon
before dispersing. Surface winds will maintain a northerly
component through this TAF period with sustained speeds between
5-10 kts.
MJA
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
WFO ILX
Area Forecast Discussion
National Weather Service New Orleans LA
904 PM CDT Fri May 19 2023
...New UPDATE...
.UPDATE...
Issued at 851 PM CDT Fri May 19 2023
Overall, current forecast looks to be tracking well. We`ve had a
few isolated showers flirting with the northeast corner of the CWA
since sunset, with very limited areal coverage. Even those appear
to be dissipating at this time. Can`t totally rule out additional
isolated development later in the night, but probabilities well
below the 15 percent threshold to carry in the ZFP.
Winds, temperatures and dew points currently in line with
forecast. An initial look at the 00z HRRR depicts a slightly
earlier convective initiation Saturday afternoon than earlier
runs, but not enough of a difference to shift the Saturday portion
of the forecast at this time.
Update that will be transmitted shortly is primarily to remove the
today portion of the forecast.
&&
.SHORT TERM...
(This evening through Saturday night)
Issued at 302 PM CDT Fri May 19 2023
Tonight through Sunday morning, high pressure will dominate the
upper level pattern ahead of a weak frontal system that moves
through Saturday night/early Sunday morning. Southerly surface
winds will help to enhance warm air advection and moisture
advection across the area, which will increase instability across
the environment. Weak upper level divergence during the daytime
hours Saturday will help to increase the buoyancy in the
environment. As a result, scattered showers and storms will be
possible Saturday, mainly during the afternoon hours ahead of the
system. Generally, convection will form around the coastal areas
more Saturday afternoon, especially along the MS and LA coastal
areas associated with the weak frontal boundary. Then, scattered
to numerous showers and storms will be possible Saturday
night/early Sunday morning as the shortwave frontal system moves
through the area.
As a result of lower cloud cover chances as we move
toward the weekend and generally light wind speeds, the
temperatures will be quite warm again going into the weekend with
highs in the low 90s and heat index values in the upper 90s.
There is still some models indicating high cloud cover tomorrow (~60%
or higher) due to higher rain chances and the system approaching,
so NBM temperatures were left in the forecast for now for
Saturday. People still need to remember to hydrate and wear loose
fitting clothing as we progress toward Summer. MSW
&&
.LONG TERM...
(Sunday through Thursday night)
Issued at 302 PM CDT Fri May 19 2023
Well definitely looks like we are fully in the process
of moving into Summer to start the week off next week but that could
quickly change. Warm humid conditions with daily rain chances pretty
through Tuesday, possibly Wednesday. That said there are some
sizable differences in the main two medium range operational runs of
the GFS and ECMWF with the evolution of the mid lvl pattern at the
end of the work week. Each of these also have support from their
respective ensemble means. In addition the Canadian is in its own
camp as well but does lean towards the GFS and GEFS. The GFS side
would suggest much cooler and maybe slightly better rain chances
while the EC side is warmer and drier yet also below the NBM at
this time. With that not going to make any major changes to the
forecast from the NBM except to tweak down just to get closer to
the EC temps at least until there is a better target to focus on.
In addition this is at day 6/7/8 so there is time to see how
things will evolve before jumping one way or the other and no real
need to dig too deep yet.
Beginning Sunday we will have a stalled weak boundary to deal with
just off the coast from Saturdays activity. This obviously could lead
to some coastal storms but just north of the coast along I-12 north
and across the MS coast we should see drier conditions and even drier
LL air leading to a fairly pleasant late May Sunday afternoon. H925
temps around 19-20C would translate to around lower mid 80s for much
of the area and with dewpoints in the lower 60s to near 70 the
apparent temps will not be a concern with Heat Index readings maybe
just topping 90 in a few areas; not bad for late May on the weekend.
Rain may not be completely out of the question though as there could
be a small s/w that moves across the southern Plains and through the
Lower MS Valley Sunday and could bring some showers and
thunderstorms to far eastern zones, mainly east of I-55. This is
associated with all of the energy currently over the Baja and
western Mexico but whether or not it moves over this way could be
the beginning of how we see things evolve next week. The ridge from
the extreme western Gulf and stretching to the NNW into the southern
Plains and how strong it is may give us our first clue about how the
pattern will evolve. That piece of energy will be dictated by the
strength of the ridge. A stronger ridge will slow it down, push it
more north, or even block. A weaker one will allow it to slide
through into the southern Plains and Lower MS Valley by late
Saturday and through Sunday.
To start the week the boundary will likely mix out/decay and likely
a more zonal mid lvl flow regime initially however The development of
a closed low over the sern CONUS or deep L/W trough along the
Atlantic coast will begin to take shape by Tuesday and more so
Wednesday. This should put the region into northwest flow aloft
eventually or even N to NNE flow. Monday should initially be quite
similar to Sunday but with a little moderation thus slightly warmer
and more humid. Afternoon convection is more likely Monday and then
on Tuesday just before mdls start to diverge we should be back into
the upper 80s to lower 90s with scattered afternoon convection. By
Wednesday and through the remainder of the week things are more p in
the air but at the very least we should be cooler and could be below
normal for temperatures, always a welcome site for late May and into
the Summer. /CAB/
&&
.AVIATION...
(00Z TAFS)
Issued at 631 PM CDT Fri May 19 2023
Isolated SHRA have developed over the last hour just east of KMCB
and over downtown New Orleans. Can`t rule out them impacting
terminals entirely, but with sunset approaching, they are expected
to dissipate in the next couple hours. At this time, don`t expect
TSRA near KHBG to make it far enough south to impact local
terminals before they dissipate.
Overnight, expect some MVFR visibilities at KMCB around sunrise,
and can`t rule out a brief period of IFR entirely. At remaining
terminals, threat is pretty low for any significant restrictions.
Any restrictions at KMCB should improve by 14-15z.
Question then becomes the convective threat with the frontal
boundary on Saturday. Northwestern terminals...KMCB/KBTR/KHDC
could see scattered convection by mid-afternoon, with remaining
terminals probably holding off until near or after 00z Sunday.
Currently don`t expect areal coverage to merit any more than VCTS.
&&
.MARINE...
Issued at 302 PM CDT Fri May 19 2023
Generally, we will have good weather conditions going into the
next week. Winds will be generally light to moderate (<15 kts) and
southerly to westerly through Sunday morning. A weak frontal
system will move through Saturday, so winds Sunday through
Wednesday morning will be generally moderate (<15 knots) and
northerly in direction. Wednesday through Thursday, winds will be
stronger as the pressure gradient increases some. Currently, winds
will be easterly and generally <15 kts, but conditions will be
approaching exercise caution headlines (~15 kts). So, we will
monitor for changes as we get closer. MSW
&&
.PRELIMINARY POINT TEMPS/POPS...
MCB 67 90 64 81 / 0 40 30 30
BTR 72 93 69 85 / 0 20 20 30
ASD 72 93 69 86 / 0 20 30 30
MSY 73 92 73 85 / 0 20 20 30
GPT 72 90 70 85 / 10 20 30 30
PQL 70 90 69 87 / 10 20 30 30
&&
.LIX WATCHES/WARNINGS/ADVISORIES...
LA...None.
GM...None.
MS...None.
GM...None.
&&
$$
SHORT TERM...MSW
LONG TERM....CAB
AVIATION/UPDATE...RW
MARINE...MSW
Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
629 PM CDT Fri May 19 2023
.SHORT TERM...
Issued at 250 PM CDT Fri May 19 2023
Through Saturday night...
A weak surface cold frontal trough is currently moving across
northeastern IL into northwestern IN. Areas along and ahead of
this front (generally areas east of I-55) will continue to be the
favored area for scattered showers and even a couple of
thunderstorms for the next few hours this afternoon before the
activity gradually sags southward out of the area with the front
into early this evening. Elsewhere, including most of the Chicago
metro and Rockford areas, the precipitation threat has ended.
However, hazy conditions (with reduced visibilities) are expected
to persist for a few hours this afternoon due to some of the
Canadian wildfire smoke mixing down to the surface in the wake of
the front. This is expected to only last for a few hours, with
conditions improving from north to south into this evening.
Otherwise, dry and seasonable weather is expected for Saturday,
with inland highs topping out in the low 70s under mostly sunny
skies. However, an onshore wind will make for cooler conditions
(around 60) along the northeastern IL and northwestern IN Lake
Michigan shores.
KJB
&&
.LONG TERM...
Issued at 250 PM CDT Fri May 19 2023
Sunday through Friday...
The upper-level flow pattern for the upcoming week will be
characterized by a pronounced ridge that will slowly progress
eastward across the central CONUS before a cut-off upper-level low
becomes established over the Gulf Coast Thursday into Friday and
sets up a Rex Block that appears likely to linger around through
next weekend. At the surface, high pressure will be prevalent over
the northeastern quadrant of the CONUS through much of this time
period and will keep things mostly quiet weather-wise in this part
of the country with most of any notable weather next week remaining
confined to the Great Plains and Southeast.
For the NWS Chicago CWA, this means that the Sunday through Friday
time frame will likely feature little to no precipitation, plenty of
sunshine, light winds, above normal temperature readings for this
time of year, and comfortable humidity levels. Daily lake breezes
can also be expected during this time, resulting in cooler
temperatures near the lake each day. The lone "fly in the ointment"
for next week, as the discussion from the preceding overnight shift
put it, may be the continued influence of Canadian wildfire smoke as
predominantly northwesterly flow downwind of the Canadian Rockies
will likely shuttle additional smoke plumes towards the Great
Lakes over the coming days. The latest RAP-Smoke output suggests
that skies here on Sunday will likely be bereft of any smoke,
though we may not be as lucky come Monday or Tuesday. Beyond that,
the smoky sky outlook is less clear (no pun intended), but if the
Canadian fires persist, then it`s not unreasonable to think that
we may be seeing milky skies and filtered sunshine for much of
next week, especially when considering the expected stagnant
weather pattern here.
Ogorek
&&
.AVIATION...
For the 00Z TAFs...
Aviation Forecast Concerns:
* Northeast winds shifting back to the north-northwest early this
evening at ORD, and mid-late evening at MDW.
* MVFR/low VFR visibility in smoke improving to VFR this evening.
* Wind shift to northeast with another lake breeze Saturday by
midday for ORD/MDW.
Strong lake breeze push developed into ORD/MDW behind the earlier
cold front, despite gusty north-northwest winds. MKE and ORD
terminal Doppler radars show boundary has stalled northwest of ORD
and was starting to shift back to the southeast, thus expect
winds at ORD to shift back to 340-ish in the 01Z timeframe based
on extrapolation of the boundary on radar. Should see a similar
shift at MDW, though likely not until later this evening. Winds
may continue to gust above 15 kts for a time before eventually
settling down to around 10 kts late evening/overnight. Surface
high pressure will drift into the region Saturday, with the
weakening gradient again allowing a northeast wind shift behind
the lake breeze. Could be slightly later, say 17-18Z for ORD, but
with relatively low confidence at this time have maintained 16Z
from previous forecast.
Still seeing 5-6SM visibilities in smoke across the Chicago
terminals, but RAP near-surface smoke forecasts suggests this
should clear out this evening with winds turning northwest again.
Otherwise, VFR conditions expected throughout the remainder of the
TAF period.
Ratzer
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...None.
IN...None.
LM...None.
&&
$$
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Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
1101 PM CDT Fri May 19 2023
.UPDATED for Aviation Discussion...
Issued at 1059 PM CDT Fri May 19 2023
&&
.DISCUSSION...(This evening through Friday)
Issued at 217 PM CDT Fri May 19 2023
KEY MESSAGES:
- Brisk tonight into Saturday morning as lows drop into the low to
mid 40s.
- Pleasant stretch of late-Spring weather forecast through middle of
next week.
- A warming trend is expected from the weekend onward into next week.
If you`ve been waiting for a nice stretch of Spring weather to enjoy
before the Summer heat ramps up... this is it! There has been little
change from the previous forecast update and in this case thats good
news. Today`s weather has played out as expected as our stratus deck
and cold air aloft have kept temperatures in check. Skies will clear
out this evening into Saturday morning as a sprawling surface high
pressure begins to settle in across the central CONUS. This allows
our temperatures to plummet into the low to mid 40s by Saturday AM.
Temperatures rebound quickly by Saturday afternoon with highs into
the lower 70s on Saturday and mid to upper 70s on Sunday. RAP
guidance does highlight the potential for another round of dense
elevated wildfire smoke late Saturday and will stick around for
Sunday.
Our warming trend continues into next week as upper-level ridging
builds east from the PAC NW into the Canadian Prairies and Northern
Plains by mid next week. NBM has highs in the low to mid 80s for a
majority of the CWA Tuesday through the end of the period as
southwesterly flow will advect warm air into the Upper Midwest
throughout the period. An impressive dry signal is present in both
the EPS and GEFS through next Wednesday as ridging limits any threat
of convection or precipitation. Our next potential system will begin
to suppress the ridging across the Northern Plains, but there is a
wide spread in with timing and intensity differences. This is
apparent as NBM PoPs edge higher for the end of period with slight
chance/chance PoPs Friday.
&&
.AVIATION...(For the 06Z TAFS through 06Z Saturday night)
Issued at 1059 PM CDT Fri May 19 2023
VFR conditions throughout. Expect clear skies overnight and Saturday,
with north/northwest winds becoming more southwest.
KMSP...
No weather-related aviation concerns. VFR conditions throughout.
Expect clearing skies overnight, with north/northwest winds becoming
more southwest on Saturday.
/OUTLOOK FOR KMSP/
Sun...VFR. Wind SW backing to SE around 5 kts.
Mon...VFR. Wind S 10G15kts.
Tue...VFR. Wind S 10G20kts.
Wed...VFR with -SHRA possible late. Wind S 10G15 kts.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
MN...None.
WI...None.
&&
$$
DISCUSSION...BPH
AVIATION...JRB
Area Forecast Discussion
National Weather Service Marquette MI
655 PM EDT Fri May 19 2023
.SHORT TERM...(Tonight)
Issued at 358 PM EDT FRI MAY 19 2023
Water vapor imagery and RAP analysis shows a closed mid-level low
circulation near Eagle River. Wraparound moisture and deep layer q-
vector convergence associated with the low is supporting isolated to
scattered showers mainly over Lake Superior and the western counties
of the U.P at this time. There is some conditional instability
associated with the cold core of the mid-level as noted on the fcst
soundings as mid-level lapse rates are 7C/km over central and
eastern Lake Superior. Biggest inhibiting factor for more organized
convection is abundant cloud cover over the area so only showers
expected into this evening and no thunder. Highs today under cloud
cover have ranged from only the 40s west to mostly lower to mid
50s central and east.
Tonight, models indicate the mid-level low will slide southeast of
the U.P. later this evening as CAMs show the bulk of the shower
activity shifting from Lake Superior and west into north central and
eastern counties of the U.P. this evening before sliding se of the
fcst late tonight with the exiting closed low. Clearing skies are
expected from west to east behind the exiting closed low and min
temps could get quite chilly, especially interior west where winds
will become lightest under a building sfc ridge. Look for min temps
ranging from the mid 30s interior west to the lower to mid 40s
mainly east and south central. Could be some patchy frost interior
west.
.LONG TERM...(Saturday through Friday)
Issued at 418 PM EDT FRI MAY 19 2023
By 12Z Saturday, the low that forced showers today will be departed
and PoPs will be exiting the region. In its wake, broad midlevel
ridging will be over the central CONUS, with 500mb height anomaly of
around 10 dam upstream through Monday. This will lead to a
northwesterly flow regime and quiet weather for the weekend and
start of the next work week. Saturday will be the day of highest
fire weather concern, with minimum RH`s dropping into the 20s with
wind gusts around 15-20 mph. Sunday`s RH`s are not expected to fall
much despite dueling 1020s mb high pressures over Ontario and the
middle Mississippi Valley thanks to a dry cold front keeping
temperatures especially near Lake Superior cooler.
Monday will be another quiet day across the region as the GEFS shows
a mean high pressure near 1030mb over the Ontario/Quebec line.
Little to no fire weather concerns Monday as relaxed gradients under
the high pressure will keep winds low and minimum RH`s only fall to
the 30s.
PoPs return to the forecast Tuesday with another cold front dropping
south with a surface trough. Precipitation totals are not
anticipated to be high as even outlier solutions within the NBM only
have a few tenths of an inch of rain at SAW. NBM temperature spread
is also vast going into the midweek, with Wednesday`s high at SAW
being anywhere from 55 to 80, likely due to the models not having a
good grasp of where the cold front and associated upper level
features will be and at what strength. High model spread and
uncertainty persist into the late week, with even higher ranges for
temperatures and many low but nonzero precip chances.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 655 PM EDT FRI MAY 19 2023
Low clouds, patchy fog, and spotty showers will keep prevailing MVFR
to occasional IFR restrictions going through this evening before
drier air and clearing skies work in later tonight. IWD and KCMX
should improve to VFR early evening and at KSAW late evening or
around midnight.
&&
.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 418 PM EDT FRI MAY 19 2023
Northerly wind gusts of 20 to 25 knots over the central portions of
the lake will end tonight. Winds remain below 20 knots through
Saturday afternoon when southwesterly gusts increase to 20 to 25
knots over the west half of the lake until Saturday night. Sunday
morning, a cold front passing north to south over the lake will kick
up northerly and northeasterly wind gusts of 20 to 25 knots over the
west half of the lake. Monday, winds remain below 20 knots. Early
Tuesday morning, ahead of another cold front, southerly winds
increase to 20 to 25 knots before becoming westerly at around 20
knots Wednesday.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
None.
Lake Michigan...
None.
&&
$$
SHORT TERM...Voss
LONG TERM...GS
AVIATION...07
MARINE...GS
Area Forecast Discussion
National Weather Service San Francisco CA
559 PM PDT Fri May 19 2023
...New AVIATION, MARINE...
.SYNOPSIS...
Issued at 109 PM PDT Fri May 19 2023
Morning clouds and cool temperatures will prevail along the coast
with a robust marine layer. High pressure will bring warm
temperatures to inland areas through mid week, with slight cooling
expected thereafter. Breezy winds at times for the coastal waters
and along the coastal interface.
&&
.SHORT TERM...
(This evening through Saturday)
Issued at 109 PM PDT Fri May 19 2023
Another May day, another visible satellite image depicting
stratus along the coast. This afternoon, stratus has lingered
longer over the SF Bay, so places such as the SF Peninsula are
still in the soup of low clouds. This will likely be the story for
the remainder of the afternoon with a decent onshore gradient
push continuing through the evening in addition to a persistent,
robust marine layer. Today, sunny skies prevail inland and
temperatures will feel similar compared to yesterday with highs in
the mid to upper 60s near the coast and mid 70s to mid 80s
further inland.
On the broad scale, weather pattern will not change in the short
term with ridge high pressure residing over western CONUS and an
upper level low over the Gulf of Alaska. This means similar
weather is to be expected tonight into tomorrow with stratus
making its way inland, bringing patchy fog and cloudy skies
through the late morning Saturday.
&&
.LONG TERM...
(Saturday night through next Thursday)
Issued at 109 PM PDT Fri May 19 2023
Sunday will see a slight warmup in temperatures (a few degrees)
with high pressure lingering. However, won`t be very noticeable
along the coastline with marine influence. On Sunday, expect
inland regions to be in the upper 70s to mid 80s.
A pattern shift is expected beginning Sunday night as trough moves
into the Pacific NW from the Gulf of Alaska, which will start to
break down the ridge. Both deterministic and ensemble models show
this pattern shift starting early next week. However, there are
still different solutions on the strength/amplitude of this trough
as deepens into our area midweek.
As trough settles in, amplified ridge will set up over the
eastern Pacific, tightening the onshore pressure gradient. With
this, expecting stronger northwest winds midweek. Strongest winds
expected to stay confined over the waters, but will still be
breezier during the afternoons on Tuesday through Thurs. Another
change in sensible weather will be the cool down that will take
place as a result beginning on Tuesday lasting through the work
week. Otherwise, rain chances continue to look slim but could see
some light precip/drizzle midweek.
&&
.AVIATION...
(00Z TAFS)
Issued at 559 PM PDT Fri May 19 2023
The marine layer depth varies only slightly from north to south
this afternoon, 1500 feet Bodega Bay to 1600 feet Fort Ord per
latest profiler data. Little change in the depth of the marine
layer is forecast during the 00z taf cycle, coastal stratus and
fog /LIFR-IFR/ moving back inland tonight and Saturday morning on
onshore winds. Stratus and fog mixing out to the coastline by late
Saturday morning and afternoon.
Vicinity of SFO...Low confidence VFR holds through the evening
since stratus is along the coast and there`s a robust onshore
pressure gradient and wind; recently peak gusts to the upper 20
knots range. Model output from RAP and HREF leaning a little
earlier with stratus /IFR/ intrusion than currently forecast (07z),
forecasting between 03z and 05z. Will continue to monitor and
coordinate with the CWSU for potential amendments to forecast.
The HAF-SFO pressure gradient is 1.5 mb, SFO-SAC gradient is 4.0
mb. IFR ceiling tonight and Saturday morning, low confidence stratus
mixing even as late as 19z per latest HREF output showing stratus
holding through early afternoon.
SFO Bridge Approach...Similar to SFO.
Monterey Bay Terminals...VFR, then stratus /IFR/ moving inland
through the evening, a mix of stratus and fog /LIFR-IFR/ tonight
and Saturday morning. Patchy light drizzle developing overnight.
Stratus and fog mixing out by early afternoon, though may be slow
to mix out per recent HREF output showing stratus and fog /IFR/
quickly returning inland Saturday evening.
&&
.MARINE...
(Tonight through next Wednesday)
Issued at 443 PM PDT Fri May 19 2023
Breezy northwest winds continue across the coastal waters with
favored coastal jet regions getting occasional gale force gusts
during the afternoon today. Winds expected to increase over the
northern outer waters starting Sunday lasting into midweek next
week with gale force gusts likely, primarily north of Point Reyes.
These strong winds will lead to steepened wind wave heights.
Additionally, a long period southerly swell 3 to 5 feet at 15 to
16 seconds continues through the waters and will slowly decay into
the weekend.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
CA...None.
PZ...Small Craft Advisory from 3 PM to 9 PM PDT Saturday for PZZ530.
Small Craft Advisory until 9 PM PDT this evening for PZZ535.
Small Craft Advisory from 9 AM to 9 PM PDT Saturday for PZZ535.
Small Craft Advisory until 9 AM PDT Sunday for PZZ540-565-575.
Small Craft Advisory until 3 AM PDT Sunday for PZZ545-570.
Small Craft Advisory until 9 PM PDT Saturday for PZZ560.
Gale Watch from late Saturday night through late Sunday night
for PZZ570.
&&
$$
SHORT TERM...McCorkle
LONG TERM....McCorkle
AVIATION...Canepa
MARINE...McCorkle
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Area Forecast Discussion
National Weather Service Salt Lake City UT
403 PM MDT Fri May 19 2023
.SYNOPSIS...Above normal temperatures will continue across the
region through the next seven days. Moisture remains in place and
will continue to lead to the development of showers and
thunderstorms each day, especially over the high terrain and
adjacent valleys.
&&
.SHORT TERM (Through 12Z Sunday)...Afternoon satellite and H5
analysis show the shortwave trough overhead pinching off, with
mid-level flow beginning to shift more northerly and eventually
northeasterly as the weak disturbance is advected east of the
forecast area through the evening. With that, seeing storm motions
slow over southern Utah and begin to train off of terrain, though
a decreasingly favorable environment will limit convective
potential and the ability for storms to organize. Thus, likely to
see continued shower and thunderstorm activity through the
evening, but concern regarding hydro or wind impacts is minimal at
this time.
Smoke continues to sit over the region, advected in on the
northerly flow from southern Canada and smaller fires in the PacNW
and Intermountain West. Still thin enough to have little impact on
high temperatures for the day, though enough seems to be present
in the lower levels to have some visibility and air quality
reductions across the region. RAP forecasts suggest the smoke will
stay in place over northern Utah through at least Saturday
afternoon, thinning and perhaps clearing out for central and
southern portions of the forecast area overnight tonight. With the
evolution of the pattern through the weekend, there is likely to
be periodic improvement in the smoke before the next trough
returns the area to northwest flow stretching back into
southwestern Canada again by Monday.
With split flow solidly in place for Saturday, will see continued
instability/thermally initiated showers and thunderstorms across
southern Utah where moisture is available, though terrain-tied
showers are possible through central and northern Utah as well.
Generally expecting limited impacts as the last two days proved
unproductive with more favorable environment, though will need to
watch for better potential for training/backbuilding storms as the
overall steering flow looks to be weaker.
.LONG TERM (After 12Z Sunday)...The extended forecast period
looks to remain modestly active as we continue to move into a
continually wet early spring. A progressive ridge overhead will keep
weather consistent as it has been with warmer temperatures and nice
sunny days with the chance for some isolated showers and
thunderstorms. A PNW low developing during the first half of the
upcoming work week will take a bit of the warmth away and bring back
the potential for more widespread precipitation by midweek.
The start of the extended on Sunday looks to be more of the same as
the high pressure ridge continues to sit overhead the Great Basin
region. Before it moves out it will continue to promote warmer
temperatures with most of the CWA seeing 5-10F above climatology for
this time of year. We expect there to be a decent amount of
lingering moisture left from the departed closed low, particularly in
the southwest/south central parts of Utah, which will keep the
potential for lingering isolated to scattered showers and storms for
the afternoon/evening on Sunday and Monday. Similar to the past
several days, showers/thunderstorms are once again expected to
develop over high terrain areas before migrating off of terrain and
into adjacent valley areas before diminishing, due to the weakly
sheared environment. The light steering flow and anomalously high
PWATs will contribute to an elevated flash flood risk for normally
dry washes, slick rock and slot canyons.
Temperatures peak on Monday with highs reaching the mid to low 80s
for many valley floors while areas near St. George creep into the
90s. Temperatures fall slightly after the ridge moves out but still
expected to hold just above climatology. The evolution of the
upstream trough feature centered over the PNW starts on Monday and
it slowly begins to effect the CWA. As this trough deepens over the
CA coast its amplitude will promote much more moisture supply from
the southern US into Utah. Its strengthening low will enhance the
baroclinic zone at its leading edge as well which will help develop
better large scale forcing for storms to develop by midweek. The
path of the low remains to be somewhat uncertain but with strong
S/SW flow, ample forcing and moisture profiles over the northern
half of the CWA leaves the door open to some moderate thunderstorm
development. By late week, models depict continued column drying,
suggesting a gradual decrease in shower/thunderstorm coverage. A
persistent active and wet spring continues!
&&
.AVIATION...KSLC...VFR conditions are expected through the TAF
period at the KSLC. Diurnally driven winds under mostly clear and
sunny skies will effect the terminal. Some lowering VIS cannot be
ruled out with the presence of wildfire smoke.
.REST OF UTAH AND SOUTHWEST WYOMING...VFR conditions are expected
through the TAF period at all terminals in Utah and SW Wyoming.
Diurnally driven winds under mostly clear and sunny skies will
effect the terminal. Isolated showers and storms could break up
clear skies and bring some lower criteria when present today and
tomorrow afternoon for southern sites. Some lowering VIS cannot be
ruled out with the presence of wildfire smoke for northern sites.
&&
.FIRE WEATHER...Unsettled weather under weak high pressure in place
over the region will continue through the weekend into early next
week. Periodic moisture transport will keep shower and
thunderstorm chances around each afternoon through evening, though
with little upper-level support these will be generally limited
to areas along and adjacent to high terrain. Areas south of I-70
can expect these storms to come with the potential of locally
heavy rainfall, while further north the drier low levels will
increase the chances of strong gusty winds in the vicinity of
these showers and thunderstorms. By Monday, more widespread
precipitation coverage is expected as an area of low pressure
approaches from the northwest, increasing the chances of wetting
rain statewide.
&&
.SLC WATCHES/WARNINGS/ADVISORIES...
UT...Flood Watch through Thursday afternoon for UTZ107.
WY...None.
&&
$$
Wessler/Selbig
For more information from NOAA`s National Weather Service visit...
http://weather.gov/saltlakecity
Area Forecast Discussion
National Weather Service Tallahassee FL
1031 PM EDT Fri May 19 2023
...New UPDATE...
.UPDATE...
Issued at 1030 PM EDT Fri May 19 2023
The forecast appears to be on track this evening, updates do not
appear necessary.
&&
.NEAR TERM...
(Through Saturday)
Issued at 319 PM EDT Fri May 19 2023
A backdoor front roughly bisecting the NE Gulf Coast has helped
keep a lid on convection so far this afternoon. Satellite imagery
shows a gradual erosion of an expansive low stratus deck that
blanketed our skies since the morning hours. Meanwhile, we are
caught between an upper trough sliding into the FL Peninsula and a
building ridge from the SW Gulf. As a result, current instability
is rather meager with even some CIN noted on SPC mesoanalysis
north of the FL state line. There is still a window of opportunity
for some isolated showers and thunderstorms to develop along the
seabreeze, but prevailing northeasterly low-level flow should keep
the activity confined closer to the coast, so little inland
progression is expected. The 18Z HRRR showcases this evolution by
favoring precipitation along the FL Panhandle south of I-10 from
20-3Z.
For tonight, we are looking at warm and quiet conditions as
temperatures merely fall into the mid 60s. Low stratus accompanied
by some patchy fog likely redevelops, particularly over the
western and eastern fringes of the service area. Tomorrow,
convection may initiate earlier ahead of an approaching "cold"
front from the northwest. Rain chances peak late in the afternoon,
especially west of the Apalachicola River. The airmass will
remain anomalously moist and instability should be moderate to
support scattered showers and thunderstorms, some of which could
become severe. We also cannot forget the seabreeze.
The SPC maintains a Marginal Risk (level 1 of 5) roughly
along/northwest of a Berrien-Seminole-Walton County line valid 12Z
Sat-12Z Sun. Main threats are damaging wind gusts followed by
hail. Although convective coverage does not look great, the
environment is supportive of a low-end threat given some enhanced
flow aloft ushered in by the front`s parent trough in addition to
Inverted-V modeled soundings. Storms likely continue into the
evening thanks to the upper level support offsetting lower
instability after sunset. Outside of storms, warm weather prevails
with high temperatures ranging from the mid 80s to around 90.
&&
.SHORT TERM...
(Saturday night through Sunday night)
Issued at 319 PM EDT Fri May 19 2023
A cold front is forecast to approach the tri-state region
Saturday night into Sunday. Rain chances are expected to increase
for the weekend as the front approaches. There is a little
uncertainty regarding the timing of the front, which will impact
when the precip will arrive in our CWA, whether it`ll be late
Saturday night, or more during the day on Sunday. PoPs for Sunday
afternoon range from 30%-40% south of I-10 and along the coast, to
60%-70% north of I-10. The front is expected to stall in the
region during the day Sunday. Forecast instability is elevated for
Sunday (~1000-2000J/Kg of CAPE), along with high PWATs
(approaching 2"), allowing for thunderstorms to develop with heavy
rainfall being the main concern. Thusly, the WPC has highlighted
our eastern GA counties in a Marginal Risk (1 of 4) for Excessive
Rainfall for Sunday. Some storms may be strong with gusty winds
and frequent lightning but, the SPC has not yet highlighted any
areas within our CWA for risks regarding Sunday afternoon.
Temperatures for Sunday will be in the upper 80s to around 90
degrees for the afternoon high. The overnight lows during this
term will be around 70 degrees.
&&
.LONG TERM...
(Monday through Thursday)
Issued at 319 PM EDT Fri May 19 2023
The front will still be making its way through the CWA for the
start of the work week. Showers and thunderstorms are likely for
both Monday and Tuesday afternoons with PoPs ranging from 60%-80%,
with Monday having the highest coverage. Model soundings show
decent instability with modest lapse rates around 6 C/Km in the
mid-levels. The sounding profiles shows long, skinny CAPE which is
a good indicator for heavy rainfall. Thunderstorms on Monday and
Tuesday will be able to produce gusty winds but, the heavy
rainfall will likely be the main concern.
By Wednesday, the front will have completed its passage headed
further into the peninsula. Afternoon showers and thunderstorms
will still be possible but, drier air will have filtered in as a
surface high settles through the week. This will decrease the PoPs
for the remainder of the week (20%-30%).
Temperatures for this term will be in the mid to upper 80s along
the coast and low 80s inland. Overnight lows are expected start in
the upper 60s and cool to the low-mid 60s by Friday.
&&
.AVIATION...
(00Z TAFS)
Issued at 734 PM EDT Fri May 19 2023
Persistent MVFR cigs at ABY have stuck around all day and will
likely continue through the evening hours. DHN just went VFR, but
is on the edge of the extensive MVFR stratus deck. As time goes on
tonight, expect the MVFR cigs to expand and then lower to IFR in
the 07-09z timeframe. These cigs shouldn`t make it as far south as
last night, however. After daybreak, gradual improvement in
conditions should occur with VFR all sites by 16z. Confidence in
any TSRA tomorrow are too low to include in this TAF cycle.
&&
.MARINE...
Issued at 319 PM EDT Fri May 19 2023
Tranquil boating conditions through Tuesday with winds generally
around 10 knots or less and seas of 1 to 2 feet. The only
exception will be near thunderstorms, especially with a stalled
frontal boundary near the waters. As the front moves south of the
waters by Tuesday Night into Wednesday, northeast winds will
increase up to 15 knots and seas building to 3 feet.
&&
.FIRE WEATHER...
Issued at 319 PM EDT Fri May 19 2023
A persistently moist airmass and elevated rain chances precludes
fire concerns the next few days outside of gusty/erratic winds
from thunderstorms. Scattered convection ahead of an approaching
cold front develops late tomorrow afternoon into the evening, for
which some isolated severe weather is possible. Wetting rains
appear likely Sunday and Monday when the front stalls across the
Tri-state area.
&&
.HYDROLOGY...
Issued at 319 PM EDT Fri May 19 2023
While there will be rain chances each day through the period, the
wettest days will be on Sunday evening through the day Monday as
a frontal boundary stalls across the region. Most locations will
see around 1 to 1.5 inches of rainfall over the next week.
However, the stalled front combined with Precipitable Water values
approaching 2 inches on Sunday and Monday will lead to locally
higher amounts of heavy rainfall. This may result in flooding of
urban and low-lying areas of poor drainage on Sunday and Monday,
with localized flash flooding possible. The WPC has highlighted
our eastern GA counties on their Day 3 outlook (Sunday) for a
Marginal Risk (1 of 4) of Excessive Rainfall. On area rivers and
streams, no flooding issues expected.
&&
.SPOTTER INFORMATION STATEMENT...
Spotter activation is not requested. However, spotters are always
encouraged to safely report significant weather conditions when they
occur by calling the office or tweeting us @NWSTallahassee.
&&
.PRELIMINARY POINT TEMPS/POPS...
Tallahassee 67 89 70 89 / 10 30 0 50
Panama City 68 84 72 85 / 10 10 0 40
Dothan 64 85 69 85 / 0 40 30 60
Albany 64 86 69 87 / 0 30 20 70
Valdosta 66 86 69 88 / 0 20 10 60
Cross City 67 90 69 90 / 20 20 10 30
Apalachicola 71 84 73 84 / 10 10 0 20
&&
.TAE WATCHES/WARNINGS/ADVISORIES...
FL...None.
GA...None.
AL...None.
GM...None.
&&
$$
NEAR TERM...IG3
SHORT TERM...Montgomery
LONG TERM....Montgomery
AVIATION...Godsey
MARINE...Montgomery
FIRE WEATHER...IG3
HYDROLOGY...Montgomery
Area Forecast Discussion
National Weather Service Las Vegas NV
140 PM PDT Fri May 19 2023
.SYNOPSIS...Scattered showers and isolated thunderstorms are
expected through the weekend, especially in the higher terrain of
southern Nevada and northwest Arizona. Rainfall amounts will
generally be light, but stronger storm cells may produce gusty
winds and lightning. Shower and thunderstorm coverage is expected
to shrink daily early to mid week. Above normal temperatures are
expected to continue along with increasing southerly breezes next
week.
&&
.DISCUSSION...Tonight through the weekend.
High pressure centered over western Nevada over the weekend will
continue to provide a northeast to southwest steering flow where
storms that initiate over the mountains move into a region of
higher anomalous mid-level moisture over the deserts. This will
increase chances for strong outflow winds from thunderstorms
collapsing into a dry low-level environment.
The HRRR continues to forecast a complex of showers and storms
developing or moving into central and southern Mohave County late
this afternoon that are forecast to move into the Colorado River
Valley by early evening. Shower/storm coverage elsewhere is
expected to be more isolated in the evening and on a decreasing
trend overnight.
The shower and storm coverage area is forecast to expand to
include much of the forecast area on Saturday. Hires models have
storms initiating over the mountains by noon Saturday, with
coverage expanding throughout the afternoon, decreasing in the
evening, and then decreasing or ending after midnight. Similar
conditions and a similar story on Sunday. Overall, precipitation
amounts are expected to be generally light with an exception
across the eastern half of Mohave County where enhanced rainfall
amounts are possible Saturday afternoon/evening. The wind
environment off the HREF has much of the area under a 50% or
higher chance of seeing wind gusts over 30 mph from storms on
Saturday with a signal for gusts exceeding 50 mph in Death Valley
prior to sunset. Winds not associated with thunderstorm activity
are expected to be mostly light across the area through the
weekend with high temperatures topping out around 5 degrees above
normal each day.
Monday through Friday...
The weather pattern is forecast to change early next week as high
pressure to our northwest breaks down as shortwave energy passes
from the Pacific Northwest into the northern Rockies. Low
pressure is forecast to become the dominant weather influencer as
troughing develops over the west and the upper flow becomes
increasingly southwest across our area. With the changing weather
pattern, the area of anomalous moisture becomes focused across
the Sierra and southcentral Nevada rather than the lower deserts
as we are currently seeing. Shower and storm chances thus become
focused in these area on Monday through Wednesday. Shower coverage
decreases Tuesday and Wednesday as moisture finally gets swept
out of the area. The forecast calls for typical dry conditions for
May with increasing southerly winds.
&&
.AVIATION...For Harry Reid...Easterly component at 10 kts or less
expected through 22Z. After 22Z, forecast becomes challenging due to
potential outflow boundaries from convection. Confidence not the
highest regarding potential outflow winds coming from the west or
north between 22Z and 01Z. Around 03Z this evening, there has been
better model agreement (higher confidence) that outflow winds from
the southeast will reach the valley. Those winds may peak between 20-
25 kts. After those outflow winds subside, the rest of the night
into Saturday morning will have light winds under partly cloudy
skies. Another round of afternoon and evening thunderstorms with
strong, gusty outflow winds possible on Saturday.
For the rest of southern Nevada, northwest Arizona and southeast
California...Greatest impact from thunderstorms late this afternoon
and evening will be across southern Mohave County and lower Colorado
River Valley. Easterly wind gusts up to 35 kts expected to roll into
the lower Colorado River Valley between 01Z and 03Z. That outflow
could persist and impact the Las Vegas Valley with gusty southeast
winds up to 25 kts(KHND, KVGT) after 03Z. Then reach KDAG around
05Z. Isolated light showers expected to last well into the night
across parts of the region before skies become partly cloudy with
light winds Saturday morning. Another round of afternoon and evening
thunderstorms with strong, gusty outflow winds possible on
Saturday.
&&
.SPOTTER INFORMATION STATEMENT...Spotters are encouraged to report
any significant weather or impacts according to standard operating
procedures.
&&
$$
DISCUSSION...Salmen
AVIATION...Pierce
For more forecast information...see us on our webpage:
https://weather.gov/lasvegas or follow us on Facebook and Twitter