Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 05/29/24
Area Forecast Discussion
National Weather Service Cheyenne WY
540 PM MDT Tue May 28 2024
.KEY MESSAGES...
- Strong to severe thunderstorms mainly along and east of I-25
into the Nebraska Panhandle Wednesday afternoon with large
hail and strong winds.
- Active weather pattern will continue through the weekend with
daily chances for showers and thunderstorms.
- Summertime temperatures will be on the horizon next week.
&&
.SHORT TERM /THROUGH WEDNESDAY NIGHT/...
Issued at 155 PM MDT Tue May 28 2024
Visible satellite imagery shows clouds developing over the high
terrain early this afternoon. From this, a few isolated showers and
thunderstorms are likely to develop later this afternoon. Per Hi-Res
guidance, any storms that develop will stay confined to the
Interstate 80 corridor in southeast Wyoming. Both surface
observations and model soundings show dry low-levels across the
area, so expect high-based storms with little to no rain and strong,
erratic winds. Could also see a few dry lightning strikes with these
storms as well. Showers and storms will dissipate later this evening.
Overnight, a LLJ will develop over the Nebraska panhandle.
Besides being a bit breezy in the panhandle overnight, south to
southeasterly flow will advect warm moist air into the eastern
half of the CWA. This will steadily increase dewpoints, leading
to the potential for some patchy fog, but will also help set the
stage for severe weather on Wednesday.
A few different dynamics at play will help spark potentially severe
convection across our eastern plains Wednesday afternoon. A strong
shortwave will move into the northern Rockies, increasing PVA across
the the CWA. At the surface, a trough across eastern Wyoming
will keep southerly winds and moisture advection into the
panhandle. This moisture will keep dewpoints in the upper 40s to
potentially low 50s across western Nebraska, favorable for the
development of storms. Most Hi-Res guidance has storms
developing off the high terrain during the early afternoon and
pushing eastward into the plains throughout the afternoon and
evening. Early on, storms will most likely be discrete, leading
to more of a hail threat. Still some model discrepancies
regarding how much MUCAPE will be present, which will likely
affect hail size and how many storms could contain large hail.
But a safe bet, based on the HRRR and GEFS will be roughly 1200
to 2000 J/kg of MUCAPE. This could lead to hail up to ping pong
ball size. As storms push further east, they will become
clusters, and lead to more of a wind and strong outflow threat,
with possibly a few embedded hailers. By the evening, most of
the storms will have pushed out of the CWA.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
Issued at 155 PM MDT Tue May 28 2024
The main concern with this portion of the forecast is when the
best chances of convection will be through the remainder of the
week into the weekend.
After an active day on Wednesday, we are looking at a frontal
boundary moving through the forecast area late Wednesday night
into Thursday morning. This front will bring breezy and drier
conditions to the area on Thursday which will limit our
convection chances compared to Wednesday. Some locations such as
Arlington and I-80 summit may even see some 45 to 50 mph wind
gusts Thursday morning into the early afternoon after the front
passes through due to some decent winds aloft combined with
downward vertical motion. Still cannot rule out a few isolated
showers and thunderstorms developing along the southern Laramie
Range on Thursday afternoon, and affect parts of the I-25
corridor during the late afternoon. However, we are not
confident that this convection will hold on past sunset
especially if anything that does develop closer to the I-80
corridor may peel off to the southeast in response to the
steering flow turning northwest and weak instability. Although,
still cannot rule some potential for strong wind gust due to
inverted V soundings. The GFS/ECMWF and NBM are showing some
signs of isentropic lift around 300k early Friday morning
across Nebraska panhandle in response to the low level jet and
moisture advection. Therefore, we are keeping some small
precipitation chances in that region.
On Friday, the deterministic solutions are still showing a
subtle shortwave moving through the eastern half of Wyoming.
As this shortwave moves across Laramie Range, we may see more
convection initiate and shift east of the I-25 corridor during
the late afternoon and evening. Cannot rule the potential for
more strong to severe storms especially in the southern Nebraska
panhandle where the shear and instability will be the greatest.
Saturday-Tuesday:
Quasi-linear upper level flow will be the main theme this
weekend. This will set the stage for daily afternoon showers and
thunderstorms especially along and east of the I-25 corridor.
Not confident about the severe potential at this point, but the
GFS/ECMWF are showing some signs of subtle shortwaves moving
through, but the exact timing of these shortwaves is uncertain
at this time. WPC clusters are still showing signs of the upper
level ridge building over the area next week. If this continues
to pan out, we will mostly likely see a switch to summertime
temperatures.
&&
.AVIATION /00Z TAFS THROUGH 00Z THURSDAY/...
Issued at 540 PM MDT Tue May 28 2024
Broad upper level ridge axis will remain over the area tonight ahead
of the next cold front. A weak disturbance aloft will result in a
few showers and thunderstorms over southeast Wyoming this evening,
mainly impacting KCYS and KLAR through 03z. Higher coverage of
thunderstorms expected for Wednesday afternoon across most of the
region.
HAZARDS/WEATHER TRENDS: Generally VFR conditions expected this
evening and tonight with increasing winds across western Nebraska
due to the low-level jet between 03z and 11z Wednesday. For KLAR and
KCYS, gusty winds over 30 knots and brief MVFR conditions with
locally heavy rainfall possible, but coverage will be less than 20
percent, so will keep VCTS in the TAF for now.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...None.
NE...None.
&&
$$
SHORT TERM...SF
LONG TERM...REC
AVIATION...TJT
Area Forecast Discussion
National Weather Service Dodge City KS
533 PM CDT Tue May 28 2024
.KEY MESSAGES...
- More showers and storms tonight
- More showers and storms tomorrow
- Relatively wet for rest of period
&&
.UPDATE...
Issued at 520 PM CDT Tue May 28 2024
Updated the short term grids to substantially raise the pops in
the west up as the HRRR has maintained the overall best
convective trends so far...and appears poised to continue the
trend with Colorado supercells congealing into more large
clusters and a line between about 00z (7 pm and late evening
from the KS/CO state line, and weakening in the less favorable
lapse rate environment east of the highway 83 corridor towards
midnight. The most favorable severe weather parameters are
focused in the far two western columns of counties, namely the
LHP (large hail parameter), boundary layer moisture and and
uncapped surface based cape area. Severe Thunderstorm Watch for
the western 6 counties remains in effect through 10 pm CDT/9 PM
MDT.
&&
.SHORT TERM /THROUGH WEDNESDAY/...
Issued at 222 PM CDT Tue May 28 2024
A complex of showers and thunderstorms will develop across the greater
region this afternoon and evening. Activity will be scattered in
nature with a hit or miss variety of activity. Rain amounts will
be widely variable with amounts between none and one inch. There
is about 30-40 kt of bulk shear, which could lead to strong to low
end severe storm activity with hail and wind being the main threats.
The main focus on this activity will be relegated to the W and SW
zones where CAPE and bulk shear is maximized. Otherwise, seasonal
lows are expected tonight with values in the upper 50s to lower 60s.
For tomorrow, PWATS will continue to remain above normal with plenty
of moisture in the lower atmosphere. As such, expect another diurnal
round of showers and thunderstorms moving out of Colorado and across
western Kansas. Some marginally severe activity with this second
round cannot be ruled out. Highs tomorrow will actually be quite
pleasant with values within a few degrees of 80F.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/...
Issued at 222 PM CDT Tue May 28 2024
The continue summer-like pattern continue through much of the business
week. This will favor seasonably warm temperatures and daily MCS
shower and thunderstorm activity. Will have to watch out for isolated
strong to severe activity each day as plenty of CAPE and marginal
bulk shear will be present for isolated bouts of strong to severe
activity. Hail and wind would be the main threats along with some
heavy rainfall. This activity will continue to remain of the hit
or miss variety, so nailing down specific rainfall amounts is an
exercise in futility. Will have to watch out though for those areas
that are lucky enough to see storms for heavy rainfall through the
next several days. Highs and lows will be relatively close to seasonal
normals with perhaps trending to slightly above normal as we finish
the business week.
&&
.AVIATION /00Z TAFS THROUGH 00Z THURSDAY/...
Issued at 532 PM CDT Tue May 28 2024
Scattered supercells in southeast Colorado are posied to enter
sw Kansas after 00 UTC, perhaps bringing severe weather with up
to 2 inch hail and 60-70 mph wind gusts initially, before
weakening as the storms reach the GCK-LBL corridor in the mid
to late evening (03-06Z). A severe risk cant be ruled out at
GCK or LBL, but heavy rain/reduced vsby/gusty outflow winds are
the heavier bet. The rain cooled boundary layer may then add to
stratus development overnight at least in the MVFR category,
developing after about 9z.
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
UPDATE...Russell
SHORT TERM...Sugden
LONG TERM...Sugden
AVIATION...Russell
AREA FORECAST DISCUSSION
National Weather Service Wilmington OH
829 PM EDT Tue May 28 2024
.SYNOPSIS...
Upper level disturbances will allow for off and on rainfall
chances through Wednesday. Dry conditions will then arrive with
high pressure Thursday through the start of Saturday before a
more unsettled weather pattern develops for the remainder of the
weekend.
&&
.NEAR TERM /UNTIL 6 AM THIS MORNING/...
Some subtle changes were made to timing of the ISO/SCT SHRA/TSRA
moving into the ILN FA this evening. Expect that this disorganized
activity will overspread the local area from W to E through the
heart of the mid/late evening hours, eventually waning toward/beyond
midnight as it approaches central OH.
The main item of interest for the mid/late evening will be the
small hail and brief gusty winds possible in the strongest
cores. Given the cool air aloft and steep LL lapse rates through
mid evening, would expect that there could be some pea-sized
hail and gusts to 35-40 MPH at times in the more well-developed
cores. But such occurrences should remain very isolated in
nature. This potential for small hail and gusty winds should
wane with eastward extent very late into the evening.
PREVIOUS DISCUSSION...
A couple of disturbances will affect the area tonight. The first
disturbance causing scattered showers across northern counties
will move east this evening, and coupled with loss of daytime
heating, showers will diminish for a time. The next short wave
arriving later tonight from the northwest is expected to
trigger additional showers and possibly a thunderstorm or two.
While still affecting mainly northern locations, the showers may
also reach farther south to the Ohio River given the stronger
and larger nature of the second disturbance. Winds gusting over
20 mph early are forecast to subside overnight. However, HRRR
shows stronger gusts occurring briefly with the second batch of
showers. By 6 am, cool lows in the low to mid 50s will be
observed.
&&
.SHORT TERM /6 AM THIS MORNING THROUGH 6 PM THURSDAY/...
Short wave energy and a surface trough will combine with a
moderate amount of moisture to produce showers and thunderstorms
on Wednesday. Area most affected will be Central Ohio where we
have categorical pops until mid afternoon. Remainder of the area
will see lower but nonzero chances for showers and a few
thunderstorms.
For Wednesday night, showers should diminish rapidly as the
disturbance weakens and moves east, coinciding with diurnal
reduction of instability.
Below normal highs in the upper 60s to low 70s are indicated,
followed by cool lows in the mid 40s to low 50s.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
Surface high pressure will remain over the region Thursday through
Friday night. Below average temperatures and dry conditions persist
on northerly, then easterly, flow.
The surface high begins to shift further to the east on Saturday
into Saturday night which will allow for the development of
southerly flow. Temperatures and moisture start to increase on the
southerly winds. Rain chances also increase on Saturday into
Saturday night as an upper level shortwave may progress through the
Ohio Valley.
Slightly above average temperatures are forecast for the start of
next week as the Ohio Valley will likely be in quasi-zonal upper
level flow. Periods of showers and storms are likely, although not
yet rendered, since the synoptic setup favors shortwaves moving
through the upper level flow.
&&
.AVIATION /01Z WEDNESDAY THROUGH SUNDAY/...
SCT to BKN VFR Cu will persist through the TAF period, with
several rounds of ISO/SCT SHRA (and perhaps ISO TS, too)
expected through the period. The first round of disorganized
SHRA will pivot through the local area between about 02z-07z,
likely impacting each site for about an hour or so each. Could
see some brief reductions in VSBYs and perhaps some gustiness
(~30kts or so) as well, but did not yet have confidence to add
in the potential to the TEMPO groups at this juncture. This
activity should push off to the E by 07z, leaving mainly dry
conditions through mid morning.
VFR CIGs will transition to MVFR by/after sunrise, persisting
through the morning hours before lifting back to VFR for the
afternoon. Additional ISO/SCT SHRA/TSRA is expected by/after
16z, with the greatest coverage focused near KILN/KCMH/KLCK
during the heart of the afternoon hours. This activity should
wane toward/after 00z Thursday, but may persist for several
hours after sunset.
WNW winds around 5kts will persist through the morning hours
before going more out of the NNW and increasing to around
10-12kts, with gusts 15-20kts, for the afternoon.
OUTLOOK...No significant weather expected.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...None.
KY...None.
IN...None.
&&
$$
SYNOPSIS...Coniglio
NEAR TERM...KC/Coniglio
SHORT TERM...Coniglio
LONG TERM...Campbell
AVIATION...KC
Area Forecast Discussion
National Weather Service Indianapolis IN
1011 PM EDT Tue May 28 2024
.KEY MESSAGES...
- Scattered showers and at least a few storms are possible late in
the day and early tonight. Strong wind gusts are the primary
hazard.
- Dry and Seasonable Wednesday through Friday, Rain chances Saturday
into Sunday
&&
.FORECAST UPDATE...
Issued at 1012 PM EDT Tue May 28 2024
Convection continues to shift east in tandem with the upper wave
passing through the region. At 02Z...storms were now across far
eastern counties and slowly weakening. Temperatures late this
evening ranged from the upper 50s to near 70.
Storms so far this evening have produced pea hail and gusty winds. A
cell merger over eastern Marion County led to a brief intensification
of the storms and penny to quarter hail in a few spots between
Cumberland and New Pal. As mentioned above...convection is weakening
but still occasionally producing gusts to near 40 mph and pea size
hail. Convection should be out of the forecast area by midnight but
a few showers may pivot back down across far northeast sections of
the forecast area late tonight as the upper wave shifts east into
Ohio.
The remainder of the night will be quiet and cool...with a steady
increase in lower stratus from the northeast during the predawn
hours. Expect these clouds to be over much of the northern half of
the forecast area by 12Z Wednesday morning. Lows will fall into the
lower and mid 50s by daybreak.
Zone and grid updates out.
&&
.SHORT TERM (This evening through Wednesday)...
Issued at 252 PM EDT Tue May 28 2024
Generally northwesterly flow exists through the depth of the
atmosphere today as a trough axis resides to our east. A short wave
embedded within the broader flow is currently diving to the
southeast out of central Canada. This feature should pass just to
our north this evening and overnight. Given the cooler air aloft,
associated with the trough, lapse rates are fairly steep today. RAP
soundings show 7-8 C/Km with super adiabatic values (up near 10C/km)
very near the ground. ACARS soundings out of IND do not show this
super-adiabatic near-surface lapse rates, however. Despite the steep
lapse rates, instability is modest with values generally between 500-
1000 J/Kg. This is in part due to a lack of moisture within the
boundary layer.
Enough lift is present within and ahead of the vort max that showers
and thundershowers are shown by most guidance. Observations tend to
agree with this, as weak radar echoes are beginning to develop in
northern Illinois and even into northern Indiana. Continued growth
is expected through the afternoon with greater concentration nearer
to the vort max. Given the steep lapse rates and relatively dry
column, strong downbursts/wind gusts are the primary hazard with any
shower or storm. Activity should diminish after 00z as diurnal
heating wanes and the boundary layer stabilizes.
Overnight, expect quiet weather with diminishing winds. Low-clouds
cover may develop towards morning from the north as the vort max
swings by. Wouldn`t rule out a few light rain showers within the
area of low clouds either. These low clouds may persist into the
morning hours but should dissipate as daytime mixing resumes and the
vort max pulls away. Surface winds should pick up again as well once
the boundary layer begins to mix. Gusts upwards of 20kt are possible
at times tomorrow afternoon. Temperatures look to be a bit below the
climatological average for this time of year due to the broad
troughing aloft. Typical values at IND are 77/57.
&&
.LONG TERM (Wednesday night through Tuesday)...
Issued at 252 PM EDT Tue May 28 2024
The long term will begin with our first consistent reprieve from wet
conditions as high pressure moves in from the north.
Troughing over the Mid-Atlantic region has brought a succession of
waves through the region, but as of Wednesday, confluence in the
upper jet stream and broad AVA will aid in raising heights through
the mid to upper atmosphere. Eventually, the amplifying ridge axis
will lead to surface high pressure over the Ohio Valley. Initially,
some semblance of surface moisture will stick around on Wednesday
(DP in the low 50s). However, by Thursday, adiabatically warmed
subsidence should drop surface dew points in the mid to low 40s.
The combination of subsidence, and drying air will lead to quiet
conditions Wednesday night through Friday. Highs will begin to
slightly increase on Thursday and Friday (Mid to upper 70s) within
well mixed PBLs. Even with deep PBLs, the lack of a LLJ should keep
winds rather calm; expect winds to top out around 10-12kts Thursday
and Friday afternoons.
The next wave of moisture/lift looks to arrive late Friday through
Saturday. Although the upper wave may arrive Friday night, the dry
low to mid levels from prior day subsidence should keep any
precipitation from reaching the ground until sometime on Saturday.
Overall this system looks to be mostly showery due to poor mid level
lapse rates, but its still too far out to have high confidence in
the details. The forecast beyond Saturday becomes much more murky
due to the relatively elevated surface moisture and remnant
boundaries and weak surface level waves in the remnants of the
Saturday upper level system.
&&
.AVIATION (00Z TAF Issuance)...
Issued at 646 PM EDT Tue May 28 2024
Impacts:
- Scattered convection possibly impacting KIND and KLAF early evening
- Gusty winds and temporary MVFR conditions possible in
showers/storms
- W/NW wind gusts to 20kt Wednesday
- MVFR ceilings expected Wednesday morning
Discussion:
Isolated to scattered convection continued across northern portions
of Illinois and Indiana early this evening in tandem with an upper
level wave. As this feature pivots southeast through the evening...
scattered convection will persist and may briefly impact KIND and
KLAF prior to 02Z. Clouds will scatter and wind gusts will diminish
into the overnight.
By predawn Wednesday...the upper wave will track into western Ohio
with lower clouds swinging back down across northern Indiana and
eventually encompassing the terminals Wednesday morning. Model
soundings support MVFR stratus with saturation through much of the
boundary layer. Cannot rule out a stray shower at both KIND and KLAF
as well in the morning but coverage too low to include at this time.
Ceilings will gradually lift into a broken VFR cu/stratocu field for
the afternoon before clouds diminish Wednesday evening. N/NW winds
may periodically gust to around 20kts on Wednesday.
&&
.IND WATCHES/WARNINGS/ADVISORIES...None.
&&
$$
UPDATE...Ryan
SHORT TERM...Eckhoff
LONG TERM...Updike
AVIATION...Ryan
Area Forecast Discussion...Updated Aviation
National Weather Service Saint Louis MO
1032 PM CDT Tue May 28 2024
.KEY MESSAGES...
- Isolated showers and thunderstorms will move southeast across parts
of northeast Missouri and west central and southeast Illinois
through early this evening. Gusty winds are possible with the
stronger storms.
- Dry weather is expected Wednesday and Thursday with near normal
temperatures.
- The chance of showers and a thunderstorms will return Thursday
night through next Tuesday with temperatures climbing above
normal. The risk for strong to severe weather remains low.
&&
.SHORT TERM... (Through Late Wednesday Night)
Issued at 158 PM CDT Tue May 28 2024
Latest water vapor imagery is showing another shortwave trough
moving southeast across the Upper Midwest that the RAP brings the
southern end of it across the area later this afternoon and early
this evening. The weak ascent provided by this shortwave and weak
instability (RAP MUCAPES in the 500-1000 J/kg range) support keeping
isolated showers and thunderstorms across northeast Missouri and
west central and south central Illinois through early this evening.
Like yesterday, RAP soundings are showing some inverted V profiles,
so couldn`t rule out some gusty winds with some of the stronger
storms. These storms will die out after sunset with the loss of
daytime heating, and then expect dry weather through tomorrow night
as the HREF is showing a upper ridge and a surface high moving in
from the Plains.
Temperatures will be slightly cooler over the next 24-36 hours as the
surface ridge moves through the area causing the winds to veer from
northwest to northeast. this will cause weak cold air advection and
temperatures too fall slightly below normal.
Britt
&&
.LONG TERM... (Thursday through Next Tuesday)
Issued at 158 PM CDT Tue May 28 2024
There is reasonable agreement in the global models with a upper
ridge moving through the area on Thursday and a shortwave trough
moving through the Midwest slightly slower on Saturday compared to
yesterday. Thereafter, we will be in quasi-zonal flow going into
early next week which the individual models have different timing
of subsequent shortwaves. At this point the LREF has the most
members (40-50%) showing precipitation chances on Friday night and
Saturday and again Monday into Tuesday with a break in between.
Severe weather chances during this period looks relative low as
the overall CAPE/shear parameter space in the model guidance is
not nearly as supportive of the level of severe weather that we
have seen in the past week and the CIPS/CSU guidance is not
particularly impressive.
Temperatures will start out just below normal on Thursday before
climbing above normal Sunday through Tuesday as 850mb temperatures
increase and low level flow turns more south-southwesterly.
Confidence in the warm up is increasing as the NBM IQR is only
4-6 degrees through next Tuesday.
Britt
&&
.AVIATION... (For the 06z TAFs through 06z Wednesday Night)
Issued at 1031 PM CDT Tue May 28 2024
Dry and VFR conditions will prevail through the TAF period.
Jaja
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...None.
IL...None.
&&
$$
WFO LSX
Area Forecast Discussion
National Weather Service Marquette MI
725 PM EDT Tue May 28 2024
.KEY MESSAGES...
- Below normal temperatures through Wednesday night, then
warming up through early next week.
- Areas of frost expected Thursday morning.
&&
.SHORT TERM /THROUGH TONIGHT/...
Issued at 241 PM EDT Tue May 28 2024
RAP analysis shows a 500mb shortwave axis over western Lake Superior
while the main surface features are a 992mb low over Quebec and a
1026mb high over Manitoba. Surface flow will be mainly northerly
through the forecast period, which will help keep the Lake Superior
shores in the 50s for highs today while the Lake Michigan shores
stay in the mid-60s. The shortwave approaching the western portions
of the UP this afternoon has been deamplifying much of today,
reducing the forcing available for showers. Persistent cloud cover
through the first portion of the day today has also limited diurnal
heating. These have factored into a reduction in the chances of
thunderstorms in the interior west and south today, though enough
CAMs have simulated reflectivity values above 40 dBZ near Menominee
to keep at least 15% chances of thunder along the WI/MI border in
Menominee County.
Overnight, a subtle shortwave will drop from the north over Lake
Superior overnight. While some model runs in the past 24 hours had
resolved showers here, the airmass descending onto the lake should
dry out the column as it approaches the UP. There is enough upslope
forcing to keep clouds in the forecast through the overnight period
for the central UP, but rainfall is not expected. This cloud cover
will act to reduce radiational cooling, with only isolated portions
of the interior west now expected to see patchy frost overnight.
Lows will mainly be around 40 tonight.
&&
.LONG TERM /WEDNESDAY THROUGH TUESDAY/...
Issued at 431 PM EDT Tue May 28 2024
The extended forecast starts off with a quiet and dry period through
Thursday night thanks to sfc high pressure and mid level ridging
moving through the region. This is followed by precip chances for
the weekend into early next week as we track out shortwaves into the
Upper Great Lakes. Temperatures are expected to be cooler than
normal through Wednesday night, warming through the early part of
next week as ridging shifts toward the Atlantic coast and WAA
increases.
Starting on Wednesday, mid level ridging will be centered over the
Northern Plains with a trough over the Pacific Northwest and a
closed low over northern Quebec. A shortwave departing southeast
from the area early in the morning with sfc high pressure building
in over the Upper Great Lakes will result in sunny skies for the
entire UP by mid morning. This sfc high pressure extending from
James Bay will also yield dry north flow to the UP with PWATs
dropping to around 0.25" to 0.3" by the end of the day. The 5/28 0Z
NAEFS indicates PWATs of these values are below the 10th
climatological percentile for our region. With model soundings
indicating mixing up to 800 mb in the interior and around 900 mb by
the lakeshores and in the east, min RHs Wednesday afternoon are
expected around 25-30%. This means the UP flirts with borderline
elevated wildfire conditions as the west is warmer with highs in the
mid 60s, but gusts stay mainly below 15 mph. Slightly cooler temps
are expected over the east in the 50s near Lake Superior to low 60s
in the interior with gusts approaching 15-20 mph. That being said,
the wet pattern we have observed over the last few days leaves
little fire weather concerns at this time.
PWATs continue to drop for Wednesday night (nearing the minimum of
the NAEFS climatology of 0.15" to 0.25") with sfc high pressure
continuing to build over the Upper Great Lakes. Good radiational
cooling will bring lows below normal into the 30s, coldest in the
interior. With near calm conditions, a dry airmass, and colder
temps, areas of frost are likely away from the Great Lakes
lakeshores late Wednesday night into Thursday morning.
Thursday sees more mixing and dry conditions similar to Wednesday as
mid level ridging builds in. While mixing is not expected to be as
high, temps are expected to be warmer in the upper 60s to mid 70s in
the interior with cooler temps by the lakeshores. This brings min
RHs in the interior into the 20% range, higher near the lakeshores
(30-50%). Winds are expected to be lighter (gusts mainly below 15
mph save for the Keweenaw), so wildfire conditions stay low.
Thursday night brings lows mainly in the 40s under mostly clear
skies.
PoPs return to the forecast on Friday as a weak cold front moves
into the west. With minimal instability (highest CAPE below 100
J/kg) and a weakening frontal boundary, mention of thunder was
removed from the forecast through Friday night. Chances for showers
and thunderstorms increase on Saturday as a shortwave moves from the
Northern Plains Friday night over just north of Lake Superior late
in the day Saturday with ridging shifting toward the Atlantic coast.
An additional shortwave lifts northeast from the Southern Plains
Friday into the lower part of the Great Lakes Basin for late in the
weekend. Another shortwave tracks east from the northern Rockies
Sunday night through the Great Lakes region Monday/Tuesday ahead of
a deeper trough for late next week. The rapid shortwaves progressing
through the region this weekend into next week yields a wetter
pattern for the weekend into early next week. That said,
accumulations are not expected to be high as NBM probabilities of at
least 0.1" of QPF in a 24 hour period for the most part stay below
50%. With spread in the guidance among timing and track of the
shortwaves, opted to leave NBM PoPs as is.
&&
.AVIATION /00Z TAFS THROUGH 00Z WEDNESDAY/...
Issued at 715 PM EDT Tue May 28 2024
Expect VFR conditions to prevail in this forecast period at all
TAF sites under surface high pressure. The biggest threat to VFR
is a low-chance probability (around 20%) of some MVFR clouds
developing at SAW this evening. Isolated showers early this
evening are not expected to impact the terminals and are not
mentioned in the TAFs. Gusty northerly winds to 20 knots at SAW
will die down after sunset.
&&
.MARINE...
Issued at 431 PM EDT Tue May 28 2024
High pressure builds southeast into the Great Lakes through tonight,
slowly continuing southeast over the Great Lakes Basin into this
weekend. This leaves light northerly winds through tonight, mainly
below 20 knots; variable winds around 5 to 15 knots are expected for
Wednesday and Wednesday night. With probabilities of winds exceeding
22 knots below 20% through this weekend, winds are expected to
mainly remain below 20 knots into the early part of next week with
no major systems in the vicinity of Lake Superior.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
None.
Lake Michigan...
None.
&&
$$
SHORT TERM...GS
LONG TERM...Jablonski
AVIATION...Voss
MARINE...Jablonski
Area Forecast Discussion
National Weather Service Pocatello ID
220 PM MDT Tue May 28 2024
.SHORT TERM...Today through Wednesday Night.
Early afternoon satellite imagery shows a H5 shortwave trough
lifting out of the Great Basin with radar imagery showing strong
thunderstorms beginning to develop in and around the Magic Valley
and WRN CNTRL Mountains. This trough will be the main driver of
convection today which aided by 300-600 J/kg of SBCAPE, 20-40 kts
of 0-6km shear, and steep 8-10 degree 700-500 mb lapse rates, will
support the potential for strong downdrafts and dry microbursts,
supporting gusts in excess of 50 mph.
We have already seen a line of showers pass through the CNTRL
Mountains earlier today which with no lightning, was able to
produce 30-45 wind gusts, indicative of the convective environment
today. CAMS remain in reasonable agreement on taking these storms
currently in the Magic Valley NE and WRN CNTRL Mountains NE and
across the Snake River Plain through this evening. With the HRRR
model showing wind gust potential in that 50-60 mph range, this
lines up well with the HREF probability of sustained winds greater
than 30 kts sitting at 70-90% for the aforementioned area.
As these storms decrease in intensity after sunset, a cold front
will begin moving through SRN Idaho tonight into Wednesday which
will support strong synoptic winds during the daytime hours in
addition to keeping our isolated to scattered showers and storms
going through the night into tomorrow. As a result in the uptick
in daytime winds, have gone ahead with a WIND ADVISORY for the
ERN Magic Valley, Arco/Mud Lake Desert, and Upper Snake River
Plain which will be in effect from 6 AM to 9 PM for sustained
winds 25-35 mph with gusts up to 55 mph.
Given it is currently 83 degrees at the Pocatello Airport as of
155 PM, today will have marked the warmest day in 232 days or
since early October as many of our climate sites also see 80
degrees for the first time this year today. These above normal
temperatures will be short lived however as colder air settles in
midweek behind this cold front with highs about 10-20 degrees
colder in the 50s/60s for Wednesday. We are also monitoring the
potential for FROST ADVISORIES across portions of the Snake Plain
and ERN Magic Valley for Wednesday and Thursday nights given low
temperatures especially further north and west, hovering in the
low to mid 30s in the latest forecast each night. MacKay
.LONG TERM...Thursday through next Tuesday.
The long term will start very dry with temperatures well below
normal on Thursday with with highs mainly in the 40s and 50s
mountains and 60s valleys. Winds will be greatly diminished in the
Snake River Plain but still breezy. Generally expect 10 to 20 mph
sustained with gusts around 30 mph. Will see a warming trend
Friday into Saturday. Highs will be in the 60s and 70s Friday and
low elevations into the low 80s on Saturday. Strong zonal flow
aloft may bring at least a slight chance of showers and
thunderstorms Saturday night into Monday mainly in the central
mountains and Upper Snake Highlands. Highs Sunday through Tuesday
will be mainly 60s mountains and 70s low elevations so near or
slightly above normal. With the stronger zonal flow aloft expect
breezy conditions to continue Sunday through Tuesday with
continuing 10 to 20 mph sustained winds with gusts over 30 mph in
the Snake Plain. GK
&&
.AVIATION...For the 18Z TAFS through 18Z Wednesday.
An approaching cold front and upper level system will bring
showers and thunderstorms into southeast Idaho this afternoon and
tonight. For now have vicinity thunderstorms this afternoon and
evening at all sites and showers through tonight into Wednesday
morning as the system works east. Winds generally around 10 knots
overnight but very strong outflow gusts near any thunderstorm.
Winds will be much stronger Wednesday and expect sustained 20 to
30 knots at BYI, PIH, and IDA with higher gusts. So will have
impacts the next two days at all sites. GK
&&
.PIH WATCHES/WARNINGS/ADVISORIES...
Wind Advisory from 6 AM to 9 PM MDT Wednesday for IDZ051>055.
&&
$$