Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 07/29/19
Area Forecast Discussion
National Weather Service La Crosse WI
619 PM CDT Sun Jul 28 2019
.SHORT TERM...(This evening through Monday)
Issued at 213 PM CDT Sun Jul 28 2019
Early afternoon analysis showed the well-advertised shortwave trough
and surface low moving across Minnesota. An attached warm front
moved northward through the forecast area during the day, with a few
showers and storms going up along and south of it. Widespread precip
was seen farther west near the surface low and southward along a
cold front. The main forecast concern in the short term is severe
weather potential as this system continues northeastward toward Lake
Superior and drags the cold front through the forecast area. The RAP
has been consistent in developing plenty of shear, especially in the
low levels, as it has the low deepening and 850 mb winds increasing
rapidly toward late afternoon. Certainly looking like enough shear
for some embedded supercell structures capable of damaging wind and
even isolated tornadoes. However, severe weather potential could be
inhibited a bit by lack of instability given all the persistent
cloud cover and precip in the area. That said, latest 18Z SPC
mesoscale analysis depicted 1000-1500 J/kg of MLCAPE across much of
the forecast area, though capping does remain in place closer to the
low where the best shear will be. Overall, thinking storms will be
able to get going along the cold front late this afternoon as shear
increases, with the greatest risk for severe weather in far
northwestern portions of the forecast area, closer to the low (see
SPC Slight Risk).
As the front advances eastward tonight, expect showers and storms to
gradually decrease in intensity, before completely exiting the area
after sunrise. Gusty northwesterly wind behind the front will usher
in some quiet and cooler weather for Monday, with highs generally in
the mid 70s to lower 80s.
.LONG TERM...(Monday night through Sunday)
Issued at 213 PM CDT Sun Jul 28 2019
Much of the upcoming week looks to be fairly quiet. The upper
level ridge axis will tilt more toward the northeast and cover
much of the Upper Midwest. This will allow an area of high
pressure at the surface to sink south over the Great Lakes from
Canada early in the week and remain through the end of the work
week. Cooler and less humid air with highs in the 70s Tuesday and
Wednesday will gradually warm into the 80s for the end of the week
with an increase in humidity as well.
The upcoming weekend still looks to be in flux as to whether a
system will move across the region and bring in some rain chances
or not. Both the 28.00Z ECMWF and 28.12Z GFS show a short wave
trough topping the upper level ridge over the Plains Friday. These
models then drastically differ with the evolution of this short
wave trough. The ECMWF brings it across the region with a chance
of rain for the weekend while the GFS quickly dissipates the short
wave trough, keeps the surface high in place and would have little
to no rain for the region. The 28.12Z GEFS is also split on the
rain chances so will have some small rain chances in the forecast
for next weekend.
&&
.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 619 PM CDT Sun Jul 28 2019
The broken line of convection moving across the area will
continue to be around both airports through about the mid-evening
and will keep thunder going for awhile. After that, the
instability should be down enough for any remaining activity to
just be showers that should then move past the area very late this
evening. An area of MVFR ceilings is expected to sweep in behind
the convection and remain into Monday morning before scattering
out or lifting up to VFR ceilings. The winds will become northwest
behind the front Monday with some gusts to around 20 knots for
KRST Monday afternoon.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
IA...None.
&&
$$
SHORT TERM...CA
LONG TERM...04
AVIATION...04
Area Forecast Discussion...UPDATED
National Weather Service Brownsville TX
635 PM CDT Sun Jul 28 2019
.DISCUSSION...Updated for latest aviation discussion below.
&&
.AVIATION...For 00z TAFs...Not many changes made to previous
aviation forecast package. Latest surface observations around the
region show southeast winds gusting around 30 knots, including at
each TAF site. Winds should subside some by 02-03z, but will
still be occasionally gusty through about 04-05z tonight. Still
expecting a period of MVFR CIGs after midnight, possibly IFR at
MFE, until around sunrise (or shortly after) Monday. Southeast
winds will become gusty again by mid-morning Monday, continuing
through the afternoon and evening. Frequent gusts between 25 and
30 knots will be likely at all TAF sites. One additional side
note will be the slight chance of isolated streamer showers after
midnight and before 15z Monday, specifically at HRL and BRO, but
not enough confidence to include in the TAFs.
&&
.PREV DISCUSSION... /issued 329 PM CDT Sun Jul 28 2019/
SHORT TERM (Tonight through Monday Night): The effects of the brief
cool down from a weak cold front last Wednesday have all but worn
off as we return back to the normal July heat across the RGV and
Deep South Texas. The outer reaches of a potent upper-level ridge
centered over the SW CONUS will continue influencing the weather
across Southern Texas over the next 36 hours, keeping things hot,
dry, and breezy.
Global and guidance models keep precip. chances very low,
generally below 10%, across the CWFA in the short term. The 18z
run of the HRRR does have some light streamer showers moving into
the lower RGV just before sunrise Monday morning. Can`t completely
rule that out, although confidence is fairly low given how
shallow the lower level moisture layer will be in the area. The
best chances of convection/precipitation will be offshore through
Monday afternoon.
Observed temperatures this afternoon have been slightly higher than
originally forecast. Thus, bumped up temperatures slightly for the
rest of the day, as well as for Monday afternoon. Still expect high
temperatures on Monday to reach the mid-upper 90s for coastal
counties, near 100 degrees in the mid sections of the RGV, and 100-
103 degrees west of I69C. Heat indices will range from 103-108
degrees in the peak heating hours. Low temperatures will remain
above normal, upper 70s/near 80 degrees. Southeast winds will once
again be on the breezy side starting by late morning Monday as the
pressure gradient tightens; gusts near 30 mph possible.
LONG TERM (Tuesday through Sunday): 12Z model suite continues on the
same trend as the last several runs with some minor differences.
Overall, consistency and persistence to play into the this forecast
package with the minor differences not expected to influence the
sensible weather in the medium-long term. Synoptic setup remains
the same with broad ridge centered over the 4-corners region
dominating the overall weather for the Deep South Texas and the RGV.
The advertised mid-level low pressure trough/low is still shows some
energy at the base of the trough to pinch off and move into the NC
Gulf Tuesday. Latest GFS and ECMWF are both more elongated with this
trough as its track slowly southwest keeping the axis over the
Western Gulf. Both the GFS/EC also show a few distinct perturbations
rotating around/between the ridge and trough being directed over
portions of the Deep South Texas later Wednesday through Saturday
night. Moisture charts indicate limited atmospheric moisture with
near average pwats however some periodic intrusions of higher pwat
values pinpoint slight higher chances of convection Wednesday and
Thursday depending on the model of choice. With this said will
maintain best pops for the eastern half/third of the CWA and the
coastal waters but may need to expand isolated pops over the Western
counties Wed night and Thursday with model agreement of the
disturbances tracking near the region. Model temperature guidance
did not show much variation for temperatures or synoptic wind flow
as we move into the beginning of August so will continue with the
near to slightly above temperatures and light to moderate daytime
breezes.
Tropics...locally are quiet but will be watching an area of disturb
weather over the Eastern Caribbean that may track near the Florida
straits by next weekend.
MARINE (Now through Monday Night): Southeast winds are expected
to decrease some by sunset this evening, but will still be breezy
enough that small craft should exercise caution both on the bay
and on the Gulf waters through at least Monday morning. A SCA may
be needed for the Laguna Madre by the late morning hours Monday as
winds increase again with diurnal heating. Otherwise, moderate
seas around 3 to 5 feet will dominate the Gulf waters through the
short term. Isolated convection will be possible on the Gulf
waters, generally farther offshore through Monday night.
(Tuesday through Friday): Weak Surface high pressure becomes
centered over the NC Gulf combining with the thermal low over NE
Mexico and West Texas much of next week. Weak to occasionally
moderate onshore flow and slight seas can be expected. Isolated
showers and thunderstorms are possible each day and overnight with
the approach of a mid-level low pressure trough.
FIRE WEATHER...Portions of Zapata, Jim Hogg, and Starr Counties have
seen relative humidity values drop into the 20s this afternoon.
Hence, the threat for enhanced fire weather danger will persist
through at least sunset this evening. Monday looks to be somewhat
similar to today, with relative humidity values in the mid 20s,
relatively dry fuels, 15-20 mph 20 foot winds, and warm/dry weather
for western portions of Deep South Texas. A fire danger statement
may be needed tomorrow for Zapata, Jim Hogg, and/or Starr
Counties.
&&
.BRO WATCHES/WARNINGS/ADVISORIES...
TX...None.
GM...Small Craft Advisory for winds until 10 PM CDT this evening for
GMZ130-132-135.
&&
$$
This product is also available on the web at:
HTTP://WEATHER.GOV/RGV
Aviation Update...Mejia-67
Area Forecast Discussion
National Weather Service Cleveland OH
928 PM EDT Sun Jul 28 2019
.SYNOPSIS...
A weak cold front has stalled over the southern shores of Lake
Erie. A stronger cold front will enter the Eastern Great Lakes
region early Tuesday morning. High pressure returns over the
region on Wednesday and remains in place through the first half
of the weekend.
&&
.NEAR TERM /THROUGH MONDAY NIGHT/...
No changes with this mid evening update. Forecast on track with
scattered showers/some thunder making their way across the lake.
A few new cells developing on land across Erie Co. PA. Most of
this will be around for the next couple of hours, but cannot
rule out an additional shower/storm or two into the early
overnight. Previous discussion follows.
A weak front has stalled from west to east across Lake Erie this
afternoon. An outflow boundary from earlier convection is
currently oriented from west to east from eastern Cuyahoga
County east to Ashtabula County and southern Erie County, PA. If
any convection were to develop this afternoon, it should happen
near the weak surface outflow boundary. The rest of northern
Ohio is very capped with the EML up to 800 mb or so. Fair
weather cumulus clouds will go away around sunset this evening.
Any convection that develops over far northeast Ohio and
northwest Pennsylvania could have some gusty winds, frequent
lightning strikes, and localized heavy downpours. The latest
HRRR and 4KM Nest Hi-Res models pick up on this potential fairly
well with the isolated strong convection.
The rest of tonight will be quiet as the frontal boundary slowly
lifts northward away from the lake. Elevated cap will keep the
weather quiet. A stronger cold front will arrive late Monday
evening and Monday night. Most of Monday will be warm, humid,
and quiet as well with the EML holding tight. The front comes in
with a line of showers and storms late Monday evening from west
to east. Isolated strong storm could be possible with damaging
wind gusts but widespread severe weather is not anticipated at
this time. The front will be on the eastern edge of our local
area by sunrise on Tuesday.
&&
.SHORT TERM /TUESDAY THROUGH WEDNESDAY NIGHT/...
Overnight convection from Monday night will continue east into
Tuesday morning and proceed to weaken with diurnal minimum in
instability and increased CIN. Redevelop of a line of
thunderstorms and showers will occur along a eastward
propagating surface cold front Tuesday afternoon once the
atmosphere has recovered back enough instability. We are only
expecting 15 to 20 knots of deep layer shear, so modest MUCAPE
of 1500 to 2000 J/kg will not be enough to put our area on the
radar for severe weather. The cold front is expected to clear
our CWA late Tuesday night. There will be enough residual
instability left on Wednesday for some post-frontal scattered
showers and thunderstorms during the afternoon hours,
particularly over the western portion of our CWA. High pressure
slowly builds in from the northwest on Thursday, allowing for
mostly sunny skies and nearly no chance of precipitation.
Temperatures in the short term period will be a little cooler than
the previous several days. High temperatures will generally be
around 80 degrees with lows in the low to mid 60s, which is right
around average for most areas.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
High pressure will continue to dominate our weather on Thursday
night and into Friday. Friday should be fairly similar to Thursday`s
weather. Saturday should remain dry, though so of the long range
models are showing some precipitation creeping in from the
southeast. Will keep low pops for now but it`s quite possible this
will change in the next couple of updates.
&&
.AVIATION /00Z Monday THROUGH Friday/...
Cluster of thunderstorms across Ontario/Lake Erie this evening
will likely impact ERI after sunset. This will bring temporary
IFR conditions and gusty winds within the heaviest rain. Will
amend if storms maintain strength across the lake. A storm or
two will be possible through the early overnight until a front
in the vicinity lifts north. All other sites expecting VFR.
Southwest winds will pick up around 25 knots Monday. A slow
moving cold front and associated showers/scattered thunderstorms
will reach the western terminals before 00Z Tuesday. An isolated
storm or two possible ahead of this during the afternoon Monday.
OUTLOOK...Non-VFR possible Monday night through Tuesday.
&&
.MARINE...
Southwest winds of 10 to 15 knots over Lake Erie will briefly
diminished slightly this evening before increasing again and
persisting in the 10 to 20 knot range through Tuesday. Waves
will be on the higher end through period, generally 2 to 4 feet,
especially east of the Geneva-on-the-Lake. While it`s not
expected to reach Small Craft criteria, there could be some
brief periods of 3 to 5 foot waves. Showers and thunderstorms
are expected to traverse the lake from west to east on Tuesday
ahead of a cold front. Winds behind the cold front will shift to
to northerly with scattered post-frontal showers and
thunderstorms on Wednesday, particularly over the eastern half
of the lake. Winds will continue to veer on Thursday to
northeasterly as high pressure builds in from the upper Great
Lakes to over Lake Erie by Thursday afternoon.
&&
.CLE WATCHES/WARNINGS/ADVISORIES...
OH...None.
PA...None.
MARINE...None.
&&
$$
SYNOPSIS...Griffin
NEAR TERM...Griffin/Oudeman
SHORT TERM...Saunders
LONG TERM...KEC/Saunders
AVIATION...Oudeman
MARINE...Saunders
Area Forecast Discussion
National Weather Service Cheyenne WY
1002 PM MDT Sun Jul 28 2019
.UPDATE...
Issued at 836 PM MDT Sun Jul 28 2019
Conditions still on track for critical fire weather conditions
across southwest Carbon County Monday. Winds look even stronger
for Tuesday across Carbon County. Decided to upgrade the Fire
Weather Watch to a warning for Monday and a Fire Weather Watch for
Tuesday. Updates have been sent.
&&
.SHORT TERM...(This evening through Monday)
Issued at 309 PM MDT Sun Jul 28 2019
So far the NAM 4KM Nest and HRRR are handling the convection coming
south out of South Dakota well, but appear to be overplaying the
initiation of convection off the South Laramie Range and onto the
plains of southeastern Wyoming. However, latest visible satellite
imagery showing some towers starting to go up over Platte and
northern Albany Counties. Will hold onto small PoPs for isolated
thunderstorms across southeastern Wyoming a bit longer for today.
Also added in mention of some storms could be severe with large
hail and damaging winds given vertical thermal/moisture profiles
through 02Z. Storm motions will be from the northwest to the
southeast through early evening.
For Monday...expect near similar conditions with some storms
initiating near the Black Hills of eastern Wyoming sliding down to
the southeast into parts of east-central Wyoming and possibly the
northern Nebraska Panhandle late in the day, with a few storms
possible forming off the south Laramie Range late afternoon. Storm
motions are expected to be similar. Again for tomorrow, we could
see a few stronger to severe storms (fairly isolated) with the
main concerns being downburst winds and large hail. Dry and warm
conditions expected west of the Laramie Range with some Fire
Weather issues of concern for parts of Carbon County Monday
afternoon (see Fire Weather portion of this discussion).
.LONG TERM...(Monday night through Sunday)
Issued at 309 PM MDT Sun Jul 28 2019
No big changes to what we saw with the 12Z runs of the longer
range models. A large ridge of high pressure will remain in place
over the desert southwest extending into the southern Rockies
through Tuesday, then a bit of a pattern change comes into play
midweek with a series of upper disturbances riding east along the
southern edge of the midlevel westerlies. By late week, the ridge
moves far enough east to bring in some monsoonal moisture to
southern Wyoming. As midnight shift alluded to, the latest climate
guidance continues to suggest temperatures will remain near
normal with above average precipitation chances through the
beginning of August.
&&
.AVIATION...(For the 06Z TAFS through 06Z Monday night)
Issued at 1001 PM MDT Sun Jul 28 2019
VFR. Wind gusts to 23 knots at Rawlins from 15Z to 01Z.
&&
.FIRE WEATHER...
Issued at 309 PM MDT Sun Jul 28 2019
...RED FLAG WARNING ISSUED FOR MONDAY WYOMING ZONE 304...
...FIRE WEATHER WATCH ISSUED FOR TUESDAY WYOMING ZONE 304...
Critical fire weather conditions are possible across parts of
southeast Wyoming as conditions are drying out with Haines Index
increasing to 5 and 6 along and west of the Laramie Range, but
especially across western Carbon County. A slight chance for a dry
thunderstorm is not totally out of the question Tuesday over this
same area. Additionally, winds will pick up across Carbon and
Albany counties on Tuesday as winds vertically stacked out of the
west. The Nebraska Panhandle will not see these same near critical
conditions. Reprieve will come each night with light winds and high
humidity recoveries. More moisture will work its way into the region
by Thursday.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...Red Flag Warning from noon to 8 PM MDT Monday for WYZ304.
Fire Weather Watch from Tuesday morning through Tuesday evening
for WYZ304.
NE...None.
&&
$$
UPDATE...GCC
SHORT TERM...JG
LONG TERM...JG
AVIATION...RUBIN
FIRE WEATHER...AB
Area Forecast Discussion
National Weather Service Green Bay WI
717 PM CDT Sun Jul 28 2019
Updated aviation portion for 00Z TAF issuance
.SHORT TERM...Tonight and Monday
Issued at 241 PM CDT Sun Jul 28 2019
The latest RAP analysis and satellite/radar imagery show a
returning warm front lifting northeast from west-central WI to
around Fond Du Lac early this afternoon. In a zone of elevated
moisture convergence along the front, a band of showers and storms
continue to lift northeast across central WI. Not out of the
question that a few strong storms could develop along this
boundary over central/north-central and east-central WI later
this afternoon with further destabilization. Severe weather
potential is looking low since the beefiest instability resides
south of the area. Looking further west, a shortwave trough and
developing surface low are pushing a large area of rain with some
thunderstorms across Minnesota. Thunderstorm potential with this
front and surface low remain the main forecast concern in this
portion of the forecast.
Tonight...The returning front will continue to lift northeast
across north-central and northeast WI this evening ahead of low
pressure moving across central MN and far northwest WI. A few
strong storms will be possible early this evening along the
returning front over north-central WI, as sref plumes indicate
1000-1500 j/kg of mixed layer instability lingering. Effective
shear slightly above 20 j/kg will most likely limit severe storm
potential, however. Additional strong storms could move into
central WI around mid evening ahead of the surface low, mid-level
shortwave, and within a beefy 50 kt low level jet. Although most
unstable cape values are generally progged to remain above 1000
j/kg, the stronger dynamics could bring a few strong to isolated
severe storms from southwest WI into central WI in the 8 to 11 pm
time frame. Storm intensity should gradually diminish thereafter
with waning instability and stronger forcing lifting north of the
Wisconsin border. Besides the severe threat, heavy rainfall is
possible over northern WI with amounts over an inch a distinct
possibility. Warm low temps in the middle 60s to near 70.
Monday...The trailing cold front will exit eastern WI in the
morning, which will end the shower threat by midday at most
locations. A period of low clouds will likely accompany the front
in the morning. Then should see some clearing occur in the
afternoon from southwest to northeast, but clouds may hang on a
little longer over north-central WI than further south and east.
Temps will be cooler than today, and range from the middle 70s
north to middle 80s over the southern Fox Valley.
.LONG TERM...Monday Night Through Sunday
Issued at 241 PM CDT Sun Jul 28 2019
The main issue in the long-term portion of the forecast will be
overnight fog potential along with precip timing/potential for the
end of the work week in to next weekend.
Monday night through Thursday: The aforementioned surface ridge will
continue to build across the western Great Lakes through this time
period, keeping fairly tranquil weather in place. The exception will
be Monday night as a surface trough extends westward across Lake
Superior/Upper MI. This may help to focus some increased cloud cover
an perhaps a stray showers along the U.P./WI border. Outside of
that, only some afternoon fair weather CU may develop each day,
especially Tuesday and Wednesday as the area will be on the western
side of the slowly departing upper-level trough. Otherwise, look for
partly cloudy skies, generally light winds and more comfortable
temperatures through this time period. PWAT values are expected to
drop to around 50 percent of normal for Tuesday through Thursday.
This, along with light winds, will lead to ideal radiational cooling
conditions overnight. This will allow temps to drop into the low to
mid 40s in the typically cooler locations (mainly Tues night), while
much of the rest of the area will be in the mid 40s to low 50s. This
will also lead to increased fog potential, especially in locations
that have received heavier rainfall recently. High temperatures will
be in the mid to upper 70s to near 80.
Rest of the extended: The high pressure system is expected to shift
slowly off to the east through this time period, allowing more
moist/southerly flow to increase across the area. At the same time,
models are also showing a couple shortwaves sliding through Thursday
night and again Friday afternoon into Friday night on the east side
of an upper-level ridge. The exact timing on these features is
challenging at best, which is not uncommon this far in advance of
such systems. Model solutions each differ on how quickly the surface
ridge slides eastward and how quickly these waves pass through the
area. At this point, will stick with a blend of the models, bringing
an increase in temps, some cloud cover and low precip chances late
this week into the upcoming weekend. Highs will be in the low 80s
with overnight lows in the 50s to low 60s.
&&
.AVIATION...for 00Z TAF Issuance
Issued at 709 PM CDT Sun Jul 28 2019
Periods of showers and thunderstorms are expected tonight as a
warm front lifts through the region followed by a cold front later
tonight. Considerable uncertainty exists on the forecast details,
in particular the timing of the thunderstorms. One cluster of
storms on the warm front was north of east-central Wisconsin
early this evening. Meanwhile, storms embedded within a large area
of showers will persist across the north. The southern portion of
the area will likely see a break in the rain prior to the arrival
of the cold front.
Low ceilings (MVFR/IFR are likely later tonight, especially across
the north. The entire system should push east of the area
Monday, but moist low-levels will probably lead to the development
of convective cloudiness. Anticipate MVFR bases on that early in
the day, with bases lifting to VFR by early afternoon.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
Beach Hazards Statement from 5 AM CDT Monday through Monday
afternoon for WIZ022.
&&
$$
SHORT TERM.....MPC
LONG TERM......Cooley
AVIATION.......Skowronski
Area Forecast Discussion
National Weather Service Grand Rapids MI
741 PM EDT Sun Jul 28 2019
LATEST UPDATE...
Aviation
.SYNOPSIS...
Issued at 245 PM EDT Sun Jul 28 2019
- A slight chance for a thunderstorm exists this evening mainly
east of a line from Mount Pleasant to Marshall.
- Dangerous beach conditions are expected Monday mainly north of
Saugatuck.
- Showers and thunderstorms are possible Monday afternoon mainly
south and east of a line from Mount Pleasant to South Haven. A
few storms may produce gusty winds and heavy downpours.
- Pleasant conditions are expected from Tuesday onward.
&&
.DISCUSSION...(This evening through next Sunday)
Issued at 245 PM EDT Sun Jul 28 2019
Currently temperatures are in the low to mid 80s with muggy dew
points from the mid 60s to lower 70s. SPC RAP mesoanalysis
indicates MLCAPE of 1500-2000 J/kg has developed generally along
and south of I-96 with the VWP from our radar confirming little
in the way of shear. A few showers/weak storms have recently
developed across the Detroit metropolitan area with an otherwise
chubby cumulus field generally along and east of US-131. With
continued southwesterly winds off Lake Michigan and modest upper-
level ridging overhead, we`re thinking any additional afternoon
convective development will be confined to areas east of a line
from Mount Pleasant to Marshall (and frankly mainly the I-69
corridor) with heavy rain and lightning as the main threats. A
rogue damaging wind gust or two can`t be ruled out with a collapsing
core, but such a threat should be confined to eastern parts of
the state.
Attention then turns to the low pressure system currently maturing
over the Plains. As an upper-level trough pivots northeast toward
the Great Lakes, southwesterly winds will increase after sunrise
with gusts > 30 mph common areawide (similar to Saturday). As such
dangerous beach conditions are expected all of Monday from roughly
Saugatuck northward. Perhaps beach-goers will be deterred by the
forecast for showers by mid-morning though coverage is expected to
be spotty. The afternoon hours will be different however as a cold
front swings through Lower Michigan. With ample forcing and upper-
level support, a band of showers and thunderstorms is expected to
develop or reintensify by early afternoon across central Lower
Michigan and progress eastward, with areas generally east of a line
from Mount Pleasant to South Haven east having the best shot of
seeing measurable precipitation. Forecast instability looks modest
owing to weak lapse rates, and deep-layer shear will be lacking (and
present largely within the 0-3 km layer). Even so, unidirectional
low-level flow and a linear forcing mechanism may promote gusty
winds with the strongest thunderstorms with a downed tree limb not
out of question. The greater threat will be lightning and heavy
downpours as PWATs climb toward the 2" mark with localized rainfall
totals >1" possible as suggested by the 12Z SPC HREF local
probability matched mean 6-hour QPF. The greatest activity is
expected between 18Z (2PM) and 00Z (8 PM).
The coldest mid-level air associated with the upper-level trough
will swing through Tuesday afternoon and allow for a few diurnal
showers (or a weak thunderstorm?), mainly across eastern portions
of the state where timing will be more optimally aligned. A quiet
and pleasant period is then expected from Wednesday onward as a
high pressure system settles over the Great Lakes. Highs in the
upper 70s/lower 80s, lows in the lower 50s (some upper 40s?), low
humidity, light winds, and plenty of sunshine are on the docket.
&&
.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 741 PM EDT Sun Jul 28 2019
VFR conditions will continue overnight with some areas of MVFR
arriving Monday afternoon as low clouds and rain move in.
Thunderstorms with localized IFR conditions are possible in the
afternoon as well. Winds will be southwest gusting over 20 knots
at times, especially Saturday afternoon.
&&
.MARINE...
Issued at 245 PM EDT Sun Jul 28 2019
Similar to this past Saturday, gusty southwesterly winds are
expected all of Monday with waves increasing to 4-6 feet. The
highest wind gusts/wave heights are expected generally north of
Saugatuck. A band of showers with embedded thunderstorms is possible
during the morning hours of Monday, as well. Calm conditions are
then expected from Tuesday onward with light winds and low waves.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...Beach Hazards Statement from 6 AM EDT Monday through late Monday
night for MIZ037-043-050-056-064.
LM...Small Craft Advisory from 1 AM Monday to 1 AM EDT Tuesday for
LMZ845>849.
&&
$$
SYNOPSIS...Borchardt
DISCUSSION...Borchardt
AVIATION...Ostuno
MARINE...Borchardt
Area Forecast Discussion...UPDATED
National Weather Service Pocatello ID
917 PM MDT Sun Jul 28 2019
.UPDATE...
Still looking at the possibility for isolated showers and a
couple of embedded thunderstorms overnight as a mid-level
shortwave approaches from the southwest. Better chances continue
to favor the Central Mountains, but did extend slight chance
mention of a shower south through the Eastern Magic Valley into
the South Hills/Raft River area based on latest observational and
model guidance. KB
&&
.PREV DISCUSSION... /issued 326 PM MDT Sun Jul 28 2019/
UPDATE...
Quick update to add mention of a few isolated
showers/thunderstorms through early evening across the Southern
Highlands near the UT border based on latest radar and satellite
trends. With minimal forcing and moisture available, these should
dissipate quickly with the loss of peak heating. KB
PREV DISCUSSION... /issued 223 PM MDT Sun Jul 28 2019/
SHORT TERM...Tonight through Wednesday.
A system working northeast is expected to push isolated to
scattered showers and thunderstorms into southeast Idaho early
Monday morning through evening. Best chance for the scattered
activity will be in the central mountains with isolated expected
across the remainder of southeast Idaho. Expect dry conditions
Tuesday with isolated thunderstorms in the eastern mountains near
the Wyoming border on Wednesday. Expect near normal high
temperatures Monday with expected cloud cover then a warming trend
and hot conditions on Tuesday and Wednesday as southerly flow
aloft develops.
GK
LONG TERM...Thursday through Sunday.
Expect a return of monsoonal moisture and a chance of
thunderstorms both Thursday and Friday with some drying expected
and less chance next weekend for Saturday and Sunday. May be a bit
cooler Thursday as that is most likely day for clouds and
thunderstorms with warming and hot conditions expected by the
weekend with valley temperatures well into the 90s.
GK
AVIATION...
Should remain VFR but by Monday morning expect showers and
thunderstorms to increase at the TAF sites and for now have
vicinity at all sites with VFR ceilings as well in the 8 to 10
thousand foot range. Will have much less shower and thunderstorm
activity on Tuesday with less cloud cover.
GK
FIRE WEATHER...
A "marginal" fire wx day will continue this afternoon. In NE Zone
425 and W Zone 410, min RH values of 10-15% are possible, but wind
gusts look to hold just shy of the 30 MPH threshold. In Zone 476,
min valley RHs are also heading toward 10-15% this afternoon with
some overlap with forecast 25 MPH wind gusts, but in general the
strongest gusts are forecast at mid to upper slopes, offset from the
lowest RH values in the valleys. Will continue to headline the
marginal conditions for these 3 zones today in the FWF.
Next, all eyes are on the shortwave trough forecast to approach the
region from the SW tonight. High-res models including the HREF
ensemble members and RAP are all trending wetter with an initial
push of shower/t-storm activity between about 3 AM-10 AM from SW to
NE across the forecast area, and coverage COULD even nudge into
scattered over pretty much any zone. However, considering the
nocturnal timing (diurnally unfavorable) and projected limited
instability (although some differences between various models), have
a hard time believing any embedded thunder/lightning will make it
beyond isolated coverage. This first push of activity also throws
some uncertainly into the afternoon forecast Mon, as we are
concerned that associated cloud cover could hamper afternoon surface
heating and resultant destabilization needed to fuel storms. Despite
this, a consensus of HREF members and NAM/GFS guidance does generate
afternoon t-storms, especially 1 PM to 9 PM. At this time, the best
chance of storms tipping over into scattered coverage appears to be
across the Central Mntns, and in coordination with NWS Missoula,
Central Idaho Dispatch, and GBCC, we will be issuing a Fire Weather
Watch for Zones 475/476. We would likely go straight to a Red Flag
Warning if not for the uncertainty over how morning cloud cover
might impact afternoon destabilization...the watch will allow
subsequent shifts to evaluate both model and satellite trends.
Elsewhere, will hold t-storm coverage at isolated. While the low-
levels will be fairly dry, high PWAT values may again offset this a
bit and allow heavier downpours to make it to the surface under
stronger storms, so a mix of wet/dry storms is expected. Wind gusts
to 45 MPH, small hail, and frequent lighting will also be possible.
Portions of Zones 425/410 may approach critical for both winds and
RH values Tues, but slightly more moisture and lower winds Wed and
Thurs should preclude the need for headlines. Thurs in particular
may feature another round of at least isolated storms. - KSmith/GK
&&
.PIH WATCHES/WARNINGS/ADVISORIES...
Fire Weather Watch from Monday afternoon through Monday evening
for IDZ475-476.
&&
$$
Area Forecast Discussion
National Weather Service Reno NV
133 PM PDT Sun Jul 28 2019
.SYNOPSIS...
A few thunderstorms are possible across northwest Nevada and
extreme northeast California this evening, otherwise dry
conditions are expected for the work week. Temperatures will
cool back to near normal for the week with breezy afternoons
each day. Hot temperatures may return next weekend along with a
small threat of thunderstorms.
&&
.DISCUSSION...
Moderate cumulus continues to develop across much of western
Nevada and northeast California this afternoon. A few buildups are
now forming too with tops near 25 kft and returns on radar. These
are near Truckee and Loyalton. Latest HRRR is targeting Mineral
County, but will continue to lean on the HREF overall and keep the
thunder in that we have in the northern areas. However, will now
expand that coverage west to where the current returns are and
south to the Pine Nuts. These will push off to the east. Biggest
threat will be potential dry strikes as the storms will be moving.
After today, the work week still looks rather quiet with
seasonable mid-summer temperatures and gusty afternoon winds. The
winds do not look overly strong with typical gusts around 25 mph,
locally stronger to 30-35 mph. There will be a couple weak short
waves that will move through during the week that could enhance
the winds, one tomorrow and one Thursday. Still, they are so weak,
it may not be discernible with regards to sensible weather.
The Four Corners high does try to build back westward for next
weekend. The deterministic model runs are much weaker with it.
While I don`t want to completely discount them, their respective
ensembles are actually in good agreement with the high and hot
temperatures. There is also not that much spread among the members
either. Will be continuing with the ensembles and showing the
warming temps. With the hot temps, and some more southerly flow,
moisture may return. A few thunderstorms are possible, beginning
Sunday or Monday. X
&&
.AVIATION...
Isolated thunderstorms are expected through 04Z this evening. They
will start near the 395 corridor from Topaz Lake northward in the
next 2 hours, then spread north and east. Best chances for
terminals seeing affects from storms are KRNO/KCXP/KMEV at 10-15%
through 00Z, then KNFL/KLOL 10-15% 00-04Z. Afternoon west to
southwest winds will still kick in, just be later than earlier
advertised.
Beginning tomorrow, much drier air moves in with light to moderate
southwest flow. VFR conditions and dry with afternoon and evening
SW-W wind gusts of 20-25 kts each afternoon through Friday. X
&&
.REV Watches/Warnings/Advisories...
NV...None.
CA...None.
&&
$$
For more information from the National Weather Service visit...
http://weather.gov/reno