Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 07/09/21
Area Forecast Discussion
National Weather Service La Crosse WI
1040 PM CDT Thu Jul 8 2021
.SHORT TERM...(This evening through Friday)
Issued at 207 PM CDT Thu Jul 8 2021
Water vapor satellite this afternoon shows a couple of short wave
troughs upstream of the area. The first was over North Dakota with
the second just crossing the border into northern Montana. The first
wave should pass across the area this evening with just enough
forcing to help keep the clouds in place but is not expected to
produce any showers or storms. The second wave will generate a round
of convection that should initiate this afternoon over Montana and
then roll southeast across the Dakotas overnight. The hi-res meso-
scale models suggest some remnants of this will hold together and
move across Iowa Friday. Some uncertainty on how far north this will
extend with the 12Z meso-scale models suggesting there is a decent
chance for this to move across northeast Iowa. However, the latest
08.16Z HRRR looks to be taking this a little farther south and if
this trend continues, it could possibly only be the very far
southern sections of the area that could get some rain. For now,
have trended the rain chance area farther south but have maintained
some higher chances across northeast Iowa. Either way, there should
be abundant cloud cover for much of the area Friday that will help
hold temperatures down again. Expecting highs again to only be the
70s.
.LONG TERM...(Friday night through Thursday)
Issued at 207 PM CDT Thu Jul 8 2021
From Friday night into Saturday, a series of shortwave troughs
will move along the northeastern and eastern periphery of the
western region. Still plenty of uncertainty on the placement of
this rainfall. With much of the instability well west and south
of the area, thinking that the greatest risk for flooding and
severe weather will remain out of the forecast area. Also kept the
rain chances more in the 20 to 50 percent range. A bit concerned
that the chances may be too far east and north.
From Saturday night into Monday, the western ridge will build
north and northeast of the forecast area. This will cause a cutoff
low to develop over the Central Plains and Mid Mississippi River
Valley. As shortwaves rotate around this low, some showers and
storms may pivot north into northeast Iowa and southwest
Wisconsin.
Beyond this period, the closed low starts to open up and
eventually gets picked up by the westerlies. Still plenty of
uncertainty on whether any of this rain from this system will
affect the area.
Temperatures will range from the mid 70s to around 80 this
weekend and be in the 80s next week.
&&
.AVIATION...(For the 06Z TAFS through 06Z Friday night)
Issued at 1040 PM CDT Thu Jul 8 2021
Cigs: mid level deck expected to be lowering later Fri morning with
mostly MVFR cigs then expected into Friday night.
WX/vsby: thunderstorm complex over the northern plains will dive
southeast overnight, tracking across IA/IL early on Friday. Meso
models currently favor keeping the brunt of any shra/ts chances
south of the TAF sites and will leave any mention out of the TAFs.
However, bits of upper level energy post the MCS could serve to
trigger scattered shra/ts for early afternoon. Some hints in a few
models this could occur. Will monitor and add if likelihood
increases. With clouds expected to be plentiful overnight, don`t see
a threat for valley fog at KLSE.
Winds: sub 10 kt winds to continue with mostly a southeast
direction.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
IA...None.
&&
$$
SHORT TERM...04
LONG TERM...Boyne
AVIATION...Rieck
Area Forecast Discussion
National Weather Service Birmingham AL
743 PM CDT Thu Jul 8 2021
.UPDATE...
Evening Update and 00z Aviation.
&&
.SHORT TERM...
/Updated at 0714 PM CDT Thu Jul 08 2021/
The latest 00z BMX raob has the Precipitable Water values down to
1.3 inches, lower than the latest LAPS analysis. This also puts
the Mixed Layer CAPE values lower in the 500 range. Although there
is some instability, it is a bit limited this evening. There were
also two boundaries around the area. One was along the gulf coast
and should not be any factor over Central Alabama. The other was
at the edge of the mean relative dry air, stretching west to east
near the US 80 corridor. Showers and thunderstorms have developed
along the axis from near Demopolis to near Prattville, moving
eastward. Will keep the highest pops near this boundary south and
have the activity slowly waning overnight. It appears that any
boundary that approaches from the north or northwest will be very
late tonight. I did leave the 20 pop north, but most of the
activity will hold off until Friday afternoon.
75
Previous short-term discussion:
/Updated at 1232 PM CDT Thu Jul 08 2021/
Through Friday.
Showers and storms are starting to develop across the southern
tier of counties early this afternoon with low level flow becoming
westerly to southwesterly. Best coverage of rain should remain
along the U.S. 80/I-85 corridors as we go into the afternoon and
early evening hours, where the highest overall moisture currently
resides. Based on RAP analysis, a PWAT gradient currently exists
between north Alabama (1.5 inches) as opposed to far southern
Alabama (1.9 to 2 inches). The KBMX 12z sounding came in with a
PWAT of 1.8 inches with 3500 J/kg of SBCAPE. There`s certainly
more dry air aloft today than what was observed on Wednesday, so
we can`t rule out a storm that has some gusty winds at times later
on this afternoon.
It`s possible that we could see a few storm clusters develop off
to our south that forms an outflow boundary moving northeast. PoPs
were kept in the chance range through the evening to allow for
that possibility, as well as additional mesoscale boundary
interactions. Mostly cloudy skies are expected to develop once
again during the overnight hours across at least the southern half
of the area with muggy conditions continuing.
As the weak upper trough begins to try and swing through the area
on Friday, flow will shift from the northwest aloft. Upper level
shortwave disturbances are expected to move southeastward, helping
to trigger scattered to numerous showers and storms across the
northern half of the area. We`ll have to watch the development of
these storms off to our northwest, as it could be a bit more
organized in the form of an MCS with gusty winds.
56/GDG
.LONG TERM...
/Updated at 0334 PM CDT Thu Jul 08 2021/
Friday Night through Wednesday.
Low level ridging will keep afternoon storm coverage at isolated
to scattered Saturday, but will see increases in coverage each
afternoon through the beginning of next week. An upper level low
will rotate southward into Missouri over the weekend, with weak
impulses rotating around this low through the Lower Mississippi
and Tennessee River Valleys. This added forcing will couple with
elevated moisture to increase storm coverage, particularly during
peak heating when instability is maximized. Made minor changes to
coverage areas, but no significant changes needed to the extended
this afternoon.
14
Previous long-term discussion:
/Updated at 0309 AM CDT Thu Jul 08 2021/
Friday night through Wednesday.
Low level ridging begins to amplify across the Gulf Coast Friday
night into Saturday morning as the upper trough axis shift
eastward. Meanwhile, another trough dips through the Upper Midwest
and moves into the Mid-MS Valley later in the weekend. This
should give us a brief period on Saturday where we see enough
synoptic subsidence with the height rises/ridging to limit diurnal
convection in Central AL. Model guidance has struggled with this,
so while I think we could see a decrease in coverage, scattered
thunderstorms will still be possible Saturday afternoon.
The upper trough to our northwest becomes a cut-off upper level low
pressure system Saturday night into Sunday, wedging Central AL
between a trough to the west and ridging to the east. This will
result in continued southerly moisture advection and enough synoptic
lift to generate slightly higher than normal coverage of diurnal
thunderstorm activity each day Sunday, Monday and Tuesday.
The cut-off upper level low is expected to phase back in with the
upper flow Tuesday evening into Wednesday, lifting quickly
northward. This should allow for a decrease in the forcing across
Central AL and therefore a relative decrease in rain/thunderstorm
chances as we approach the middle of next week. With that said, the
timing of when cut-off lows phase back into the overall upper level
jet flow can be very difficult for models to handle, so this
forecast will likely change in coming days as model guidance
fluctuates on that upper low evolution.
25/Owen
&&
.AVIATION...
00Z TAF Discussion.
Have no weather mentioned at any terminals, but there is a
boundary near MGM. This boundary was the dividing line between
drier air to the north and tropical air to the south. A few
showers/storms have developed on this boundary and will have to
monitor for possible addition for MGM. The activity in the south
will wane this evening. Otherwise, VFR forecast through much of
the overnight hours. There should be some LIFR ceilings
developing again tonight, but will be later in developing. It
appears that these ceilings will be around 005, with fog not as
much of an issue. The ceilings will be around generally from
10-15z. Showers and thunderstorms are anticipated on Friday.
handled this activity with PROB 30 late morning and VCTS in the
afternoon for starters. Winds will be westerly less than 5kts
tonight and west 5-10kts on Friday.
&&
.FIRE WEATHER...
Low clouds are possible early Friday morning, with ceiling
heights below 1kft across the south. These ceilings will improve
through the morning hours. Scattered to numerous showers and
storms are expected each day through this weekend, mainly in the
afternoon and evening. A humid airmass will result in high RH
values for the next several days, with light winds less than 7kts.
&&
.PRELIMINARY POINT TEMPS/POPS...
Gadsden 71 89 70 89 69 / 20 70 20 50 30
Anniston 71 87 71 88 71 / 20 70 10 50 20
Birmingham 72 89 71 89 71 / 20 70 10 50 20
Tuscaloosa 73 89 72 90 72 / 20 60 10 40 20
Calera 72 88 72 88 72 / 20 60 10 40 20
Auburn 71 87 71 87 71 / 40 60 10 40 10
Montgomery 73 90 72 92 73 / 40 60 10 40 10
Troy 72 88 72 90 72 / 30 60 10 40 10
&&
.BMX WATCHES/WARNINGS/ADVISORIES/...
None.
&&
$$
Area Forecast Discussion
National Weather Service Buffalo NY
1024 PM EDT Thu Jul 8 2021
.SYNOPSIS...
A cold front will move across the area overnight with some fog
developing and a few showers. A weak trailing system will allow
for lingering chances of showers into Friday before drier
weather advances into the area. Unsettled and humid conditions
resume by the start of next week.
&&
.NEAR TERM /THROUGH FRIDAY/...
A frontal boundary draped across the region early this evening
will finally move through as a cold front overnight. There will
be a few lingering showers with this, mainly east of Lake
Ontario. Otherwise, the main impact will be areas of fog which
will develop across Western New York, especially near the
lakeshores. Some of this fog may be locally dense. Fog already
can be seen on webcams along Lake Ontario and at Dunkirk along
Lake Erie. Prefer HRRR guidance which does a good job advecting
and spreading this fog out overnight. The fog will linger into
Friday morning.
A secondary wave in NW flow aloft will traverse the area on
Friday with a minimum in the H5 temperatures. This will result
in showers blossoming inland from the Great Lakes and moving off
to the ESE in the mean layer flow. These will be scattered in
nature, and the majority of Friday is likely to be dry.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SATURDAY NIGHT/...
Surface high pressure will begin to build into our region from the
west as the moist airmass continues to push off to the east Friday
night. This will provide mostly dry conditions overnight, with only
a chance of a lingering shower or two. Overnight low temperatures
will be in the 50s to low 60s across the Lake Plains.
Though most areas on Saturday should also see rain-free conditions,
a few light showers may pop-up in the afternoon hours. Weak cold air
advection in the mid-levels combined with daytime surface heating
will steepen lapse rates as a relatively weak upper level jet passes
over the area in the afternoon hours, which may provide the little
bit of extra forcing to sour an entirely dry forecast. Nonetheless,
very limited moisture, weak flow through the column and subsidence
courtesy of surface high pressure should limit shower coverage.
Temperatures on Saturday will peak near or just below climatological
normals for this time of year. Any showers that develop should
quickly die out as daytime heating falls off. Cloud cover should
initially diminish as well, allowing for temperatures to again drop
into the lower 60s and 50s across the region. However, temperatures
will begin to moderate as mid and high level clouds begin to build
into our region in the second half of Saturday Night.
A surface warm front pushing towards our region from the South will
bring another period of active weather beginning on Sunday. Rain
showers along the front along with with diffluent flow aloft will
gradually spread from south to north across the region. More
widespread shower activity will reach the NY/PA border in the early
afternoon and overspread much of the area shortly thereafter,
lasting right through Sunday night. Low level warm air advection
should limit lapse rates and overall CAPE, but abundant moisture
with PWATs close to 2" will bring the chance for some steady rain
and a possibly a few rumbles of thunder in the afternoon.
Temperatures will again be near normal during the day Sunday, but a
warm overnight is in store with temps in the mid 60s, a bit cooler
east of Lake Ontario.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
An upper level ridge off the southeast U.S. coast Monday will build
northward and span the eastern seaboard by mid-week. A warm front
will be track from south to north across western and north central
NY early in the week. Temperatures and dewpoints will increase with
daily chances for showers and thunderstorms. A shortwave trough near
the Upper Great Lakes is forecast to stay to the west as the strong
upper level ridge stays across the Northeast through Tuesday. This
should keep widespread severe risk low. The ridge should start to
break down Wednesday and Thursday and the chance for showers and
thunderstorms continue with an increase in southerly flow.
High temperatures will average in the low to mid 80s Monday to the
mid to upper 80s Tuesday-Thursday. Low temperatures will average in
the mid to upper 60s.
&&
.AVIATION /02Z FRIDAY THROUGH TUESDAY/...
Low moisture will increase across the area with low stratus
lowering flight conditions to IFR or lower. Lower cigs and
locally dense fog are possible, with a risk of VLIFR in any
dense fog. Greatest risk is between 06Z and 15Z at KBUF, KIAG,
and KJHW.
Fog will slowly dissipate and cigs lift on Friday, but it may
not be until Friday afternoon before conditions improve to MVFR.
Scattered showers and an isolated thunderstorm is possible.
Outlook...
Friday night...Improving to MVFR/VFR with diminishing chances
for showers.
Saturday...VFR. A chance of showers over the far west.
Sunday...VFR.
Monday...VFR/MVFR with a chance of showers and thunderstorms.
Tuesday...VFR/MVFR with a chance of showers and thunderstorms.
&&
.MARINE...
A cold front will drop south of the waters with generally light
winds and negligible waves overnight. There will be areas of fog
on the waters, which may become dense at times.
Looking ahead to the upcoming weekend...gentle to occasionally
moderate winds on Saturday will be accompanied by negligible
wave action. While winds and waves should not be an issue on
Sunday... conditions will once again deteriorate with some
showers and thunderstorms becoming likely.
&&
.BUF WATCHES/WARNINGS/ADVISORIES...
NY...None.
MARINE...None.
&&
$$
SYNOPSIS...Apffel/Fries/RSH
NEAR TERM...Apffel/Fries
SHORT TERM...PP
LONG TERM...HSK
AVIATION...Apffel/Fries
MARINE...Apffel/Fries
Area Forecast Discussion
National Weather Service Cheyenne WY
750 PM MDT Thu Jul 8 2021
.UPDATE...
Issued at 745 PM MDT Thu Jul 8 2021
Quick forecast update this evening with the expiration of the Red
Flag Warning this afternoon. Another day of dry conditions and
gusty winds are expected on Friday, but the worst conditions will
shift further west.
Isolated showers and thunderstorms will continue over southeast
Wyoming and western Nebraska this evening, but should diminish in
intensity after 900 pm. Another round of thunderstorms expected
Friday with a better potential for severe with severe storms
likely occurring later in the day/evening hours.
&&
.SHORT TERM...(Tonight - Saturday Night)
Issued at 155 PM MDT Thu Jul 8 2021
The main forecast concern/highlight over the next 24-48 hours will
be the potential for strong to locally severe thunderstorms across
portions of the area. Hot & dry today on the northern fringe of an
intense upper-level ridge encompassing much of the southwestern US
this afternoon. Fire weather conditions remain elevated especially
along and west of the Laramie Range. KCYS radar loop shows showers
and thunderstorms beginning to develop along the Laramie Range, in
western Platte County. Convection should increase in coverage over
the next few hours with a few stronger disturbances traversing the
flow on the edge of the ridge. Dew points in the 50s, coupled with
steep mid-level lapse rates are contributing to MLCAPEs up to 1500
J/kg across east central WY into the northern NE Panhandle. Expect
this to be the most likely area for any severe storms later in the
afternoon and this evening beneath 40-50 knots of H5 flow, helping
to support effective bulk shear in excess of 40 knots which should
contribute to a risk for supercell structures. We do not expect to
see this activity become particularly widespread, but potential is
there for an intense storm or two.
Stronger mid-level short wave dives south across the CWA on Friday
afternoon, yielding considerably stronger forcing than what exists
currently. 50+ knots of westerly H5 flow will give way to up to 60
knots of 0-6 km shear, which could combine with CAPE values around
2000-3000 J/kg depending on the degree of boundary layer mixing in
the hours before initiation. Convection may come in several rounds
for different areas, but primary focus will be across east central
Wyoming and the northern Nebraska Panhandle once again, first late
in the afternoon and then again during the mid/late evening. High-
resolution guidance including the HRRR and NAMNest have been quite
consistent painting numerous supercells & linear segments, roughly
between 21z and 06z. Recent westward expansion of SPCs Slight Risk
looks good based on the latest data. Primary hazards will be large
hail and damaging winds. High cloud bases should limit chances for
an isolated tornado despite substantial directional shear near the
surface.
Some shower & thunderstorm activity could linger into the early to
mid morning hours on Saturday. Otherwise, much cooler and drier in
the wake of the cold frontal passage with highs 75-85.
.LONG TERM...(Sunday - Thursday)
Issued at 155 PM MDT Thu Jul 8 2021
Quieter weather expected by the late weekend into early next week as
a ridge of high pressure builds across the CWA and an upper level
low stalling out across the Midwest. Should begin to see a warm and
dry pattern emerge with a blocking feature developing across the
eastern seaboard, allowing the low to remain fixed over the Ohio
Valley through Monday. An uptick in the temperatures is likely under
this feature, with daytime highs projected to be in the upper 80s
and even in the mid-90s for the northern portions of the CWA. With
the uptick in daytime highs, and drier conditions expected, will
inevitably raise fire weather concerns as the afternoon RH values
drop to the mid-teens. At this time, long range model guidance has
wind speeds below criteria, with in house products in good agreement
of the lower wind speeds. However, will need to reevaluate later
model runs to determine if any fire weather headlines will be
needed. Once the overall ridging pattern begins to break down across
the southwest, will see increase chances for afternoon thunderstorms
through Thursday. Even though PWat values remain higher across
southeastern Wyoming and the Nebraska Panhandle compared to Monday,
much of the good moisture advection remains to the east. Regardless,
once northwest flow sets up across the domain, combined with surface
heating, 500-1000 J/kg MUCAPE, and 40-60 kt of 0-6km shear supports
isolated strong to severe storms Wednesday and Thursday.
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 526 PM MDT Thu Jul 8 2021
VFR. Thunderstorms in the vicinity at Laramie, Cheyenne, Chadron,
Alliance, Scottsbluff and Sidney until 01Z. Wind gusts to
37 knots at Rawlins, Laramie and Cheyenne until 02Z, then to
35 knots after 15Z Friday.
&&
.FIRE WEATHER...
Issued at 405 AM MDT Thu Jul 8 2021
Well above normal temperatures expected today with humidities
dropping to 12 to 15% across Converse, Niobrara, Carbon, and
Albany counties and westerly winds gusting to 35 MPH ahead of a
cold front. Some shower and thunderstorm, likely dry thunderstorm,
activity possible with the cold front passage. Friday looks a
little bit cooler than Thursday, but for areas less impacted by
the cold front, specifically areas west of the Laramie Range,
humidities will remain 12 to 15% through the afternoon and evening
with winds gusting to 35 MPH. Saturday will be the coolest day
with higher humidity and weaker winds, but that relief is short-
lived as temperatures warm back up to well above normal with
humidity dropping to 12 to 20% Sunday into early next week.
However, winds are currently forecast to be relatively light and
variable with little to no thunderstorm activity expected.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...Red Flag Warning from 11 AM to 8 PM MDT Friday for
WYZ304-305- 307-308.
NE...None.
&&
$$
UPDATE...TJT
SHORT TERM...CLH
LONG TERM...MD
AVIATION...RUBIN
FIRE WEATHER...LK
Area Forecast Discussion
National Weather Service Des Moines IA
633 PM CDT Thu Jul 8 2021
...Updated for 00z Aviation Discussion...
.SHORT TERM.../Tonight through Friday Night/
Issued at 318 PM CDT Thu Jul 8 2021
...Increasing Risk of Severe Storms Friday Afternoon and Night...
Confidence: Medium
Main challenge is increasing severe threat Friday into Friday Night.
Remnants of the area of showers continues to move southeast into our
area and continues to fester this afternoon. Stratus that backed
into eastern and central Iowa overnight along with the fog has
lifted with some clouds lingering late this afternoon due to the
weakening area of showers. Meanwhile, over southeast Wyoming, the
southern of two short waves will begin to lift northeast later today
and tonight. A nearly stationary front this morning from a northern
stream low over Montana will also begin to push northeast tonight.
Increasing H850 winds and stronger thetae advection will focus an
area of elevated storms along this boudoir with the initial
storms over Iowa beginning around or shorter after 06z. H700 flow
is east southeast and with the expected strengthening of the low
level jet between 06z and 12z, the storms will attempt to ride
east southeast while the main synoptic boundary lifts northeast.
So, overall tonight`s focus is for the northwest/west central into
northeastern and northern sections with time through 18z Friday.
There is decent consensus on tonight`s evolution of the storms
primarily affecting areas north of I80, but still some uncertainty
on the cutoff on the southern edge as well as how far southwest
an expected outflow boundary will move with the main MCS that
forms later tonight into Friday. There is better consensus today
that at least some semblance of the storm complex will remain
ongoing through the daytime hours as it lifts into northeast Iowa
tomorrow. Tonight our 0-6km shear increases to 45 to 50 kts,
peaking from 06- 12z across northwest and then expanding to
southeast Iowa from 18z to 00z and weakening slightly into 06z.
Though there are differences in the synoptic solutions, a general
focus is coming into view. The first round of convection should
remain elevated with hail being the main threat over the
west/northwest tonight. SPC has expanded the marginal area farther
east a bit overnight to cover more of western/northern Iowa
through 12z Friday. Tonight lows will be warmer with expected
cloud cover and increasing southeast flow during the night hours.
Mins will range from the lower 60s northeast to the mid 60s over
the south/southwest.
Early indications for Friday suggest that the lingering storms
mainly north of I80 will lay down an outflow boundary back into
central Iowa. The HRRR shows a wind shift backing west southwest and
somewhat aligning/converging with the main synoptic boundary by 19-
21z. South of the boundary, daytime heating should bring highs back
into the 80s just along and southwest of the boundary. Instability
parameters increase to roughly 2000-2500+ J/kg MLCAPE south of
the boundary with strong curvature in area hodographs, 0-1km SRH
200-300 m2/s2 and forecast SR mean wind over 40 kts in a corridor
over central to southeast Iowa from mid/late afternoon through
early evening. The GFS and NAM solutions are a bit more robust and
farther northeast than the Euro today. At this time, it appears
that there will be little if any cap by late day south. Limiting
factors over a portion of south/southwest early in the event,
include a warm layer of +10C at H700 which is generally back
west/southwest of Des Moines. Thus the potential for a corridor
strong thunderstorm activity may be confined to a more narrow
region somewhere along and near the I35 corridor southeast to far
southeast Iowa just along and south of a surface warm front and
area of stronger sfc convergence during the afternoon and then
some storms moving into the southwest later in the night.
The new SWODY2 outlook for an enhanced risk covers the area pretty
well with some uncertainty yet on extent of coverage. There remains
some timing uncertainty on the afternoon uptick or into early
evening for coverage/severity with the ongoing convection in the
morning. All modes of severe are possible with a higher risk of
significant hail and significant thunderstorm winds along with
tornadoes. Given diurnal expectations, the most likely timeframe
would be from 20-23z through mid to late evening with some hydro
issues possible south into the overnight if the storms can reform
along the main sfc boundary collapsing south into Missouri and
propagate east. Similar to previous forecasts and also given high
PWATs as well as sufficient warm cloud depths, some areas may see
a quick 1 to 2 inch rainfall overnight tonight into Friday midday
with a more robust rainfall signature with the afternoon/evening
convection over the south into Friday night. Rainfall totals then
could exceed 2 to 4 inches at some locations. For now, will not
issue any hydro headlines for Friday night, given the uncertainty,
but will need to evaluate again tonight or very early tomorrow
morning. A lot of the forecast in the near term depends yet on the
overall cloud coverage early Friday morning. Lows Friday night
will drop to the mid 60s south and lower 60s north.
.LONG TERM.../Saturday through Thursday/
Issued at 318 PM CDT Thu Jul 8 2021
Confidence: Low to Medium
Models continue to struggle with the evolution of the H850 low and
subsequent chances for storms from Saturday through Monday. The
favored areas would remain over the south and east during the
period. The Euro continues to emphasize a farther south track while
the GFS/NAM are a bit farther north. The 12z GEFs H850 low track is
farther east and south by 06z Monday than the operational GFS, but
still has more northerly drift of the system into the weekend
compared to the operational Euro. For now, will maintain
rain/thunder chances into Monday with some expectation that the
mesoscale forcing will help direct the synoptic pattern farther
south with time. Overall additional rainfall of an inch or so is
possible with the H850 low near our area through Monday.
Temperatures will struggle Saturday and Sunday with some warming
into midweek with another approaching system and cool front by
Wednesday and cooler conditions into Thursday.
&&
.AVIATION.../For the 00Z TAFS through 00Z Friday evening/
Issued at 633 PM CDT Thu Jul 8 2021
VFR conditions at present, but that will be changing as the first
wave of showers and storms moves over northern Iowa after 6z. MCW
and ALO have highest chances of keeping showers and storms around
after this first wave passes with lower chances at the other
terminals. This resulted in long periods of VC wording across the
northern terminals, but tried to limit TS mention to when
confidence was higher. Stronger storms are expected to develop in
the mid-afternoon hours with the most likely terminals impacted
being DSM and OTM and perhaps FOD and ALO.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...REV
LONG TERM...REV
AVIATION...Ansorge
AREA FORECAST DISCUSSION
National Weather Service Hastings NE
838 PM CDT Thu Jul 8 2021
...Short Term and Aviation Update...
.UPDATE...
Issued at 836 PM CDT Thu Jul 8 2021
Some comments on our limited (but non-zero) rain/thunderstorm
chances later this evening-overnight:
- Overall, only cosmetic changes made thus far to the evening-
overnight forecast inherited from day shift. See excellent
previous discussion below for more assessment of our small (but
non-zero) chance for spotty and most likely non-severe activity
late tonight into early Friday.
- About the only change made to previous forecast was to delay any
mentionable (20+ percent) PoPs/chances into our far
western/northern zones until midnight (and then expanding to
more of the area thereafter), as previous forecast had small
PoPs creeping into our far west as early as 9-10 PM...which
radar/satellite/model trends now confirm will not occur that
early.
- Echoing some previous forecaster thoughts from below, clearly
the "main show" for late-night activity within the low level jet
exit region should focus pretty clearly to our north-northeast
in the general NE/SD/IA border area, but just enough limited and
very-elevated instability (mainly 700-600 millibar layer) will
exist directly over our CWA to perhaps promote isolated to
scattered shower/storm development particularly near/after 3 AM.
Needless to say, this is far from a "sure thing", as even short
term/hi-res models still show quite a bit of disparity, ranging
from a fair amount of scattered late-night/early morning
activity (per the HRRR) to practically nothing (per the 18Z
NamNest).
&&
.DISCUSSION...(This evening through Thursday)
Issued at 425 PM CDT Thu Jul 8 2021
Main concerns revolve around heat indices Friday afternoon, then
thunderstorm chances late Friday and into the weekend.
Warm and breezy conditions in place this afternoon under fully
sunny skies. S winds gusting 20-30mph have provided some relief
from the warm, muggy conditions as highs have climbed into the
upper 80s to low 90s amidst Tds as high as upper 60s in spots.
Expect similar conditions to continue thru the eve. Latest WV
imagery shows our next upper disturbance, quite clearly as a
tight/compact spin, moving SE out of S Canada into N MT.
Otherwise, remnants of Elsa can be seen moving NE along E Coast,
with another upper trough noted over the Pac NW, which will be our
disturbance for Fri night that will eventually carve out a nice
trough over the Midwest this weekend.
Tricky PoP forecast begins tonight as a small, but non-zero,
chance for at least a few tstms exists nearly all night. The first
low end potential is for remnants of High Plains convection to
move in from the W towards HWY 283 after dark and before midnight.
Several HRRR runs have shown this scenario. Not completely sold
this activity will be able to hold together, though, due to incr
CINH and fact that primary LLJ convergence should set up well N/NE
of the area. Another potential catalyst for weak convection will
be from lift on the S fringes of aforementioned MT shortwave
after midnight within highly elevated zone of instability,
generally between H7 and H5. NE half of CWA, or so, will have best
potential given track of shortwave well NE of the area, and some
of this activity may persist into Fri AM.
Attention then turns to heat and humidity for Fri aftn. Have
coordinated with neighbors to issue a Heat Advisory for KS zones
given potential for peak heat index values around 105-107F. These
areas will remain warmest tonight on steady S wind, have least chc
to be impacted from overnight convection/clds, and likely see
warmest air temps in the low 100s ahead of a sfc trough. Areas S
of this sfc trough may still see some decent Srly breezes, so
tough to gauge how much near-sfc moisture will mix out...but even
mid 60s Tds will add a few deg to the feels like temp. Further N,
the aforementioned sfc trough will likely lead to much weaker
mixing and promote pooling of sfc moisture. Air temps won`t be as
warm, generally low to mid 90s, but less mixing and better
evapotranspiration will likely lead to higher Tds in the upper 60s
to low 70s. It doesn`t appear actual heat indices will exceed
105F N of the state line, but lesser wind will make it feel just
as uncomfortable as warmer S zones.
Forecast focus then shifts to potential for svr tstms, perhaps as
early as early Fri eve, but more likely late eve into overnight.
Models generally depict the CWA in shortwave ridging/subsidence
behind tonight/Fri AM departing wave, so in the absence of some
sort of remnant MCV or strong outflow bndry (which seems unlikely
attm), think lack of upper forcing and relatively warm mid level
temps (H7 temps 12-14C) will keep most, if not all, of the CWA dry
Fri aftn. I think best chcs for aftn sfc based convection will be
E of the CWA within better zone of low level
forcing/moisture/instability and less capping. Appears our primary
concern will be for convection to develop over the central High
Plains, within zone of moist upslope flow and strong effective
shear, organize into an MCS, then propagate E/SE along mid-level
thermal gradient towards W portions of the CWA around 02-03Z. The
question then becomes how organized will the MCS become by the
time it reaches the CWA, and well will it maintain intensity into
the overnight? Not sold it is a slam dunk severe weather chc for
our CWA for a few reasons: 1) models suggest there may be a
minimum in instability over central Neb., E of the zone of
initiation and W of the CWA, where Tds remain in the 50s. 2) the
timing of the MCS into this zone of lesser instability may be
around sunset and be too much incr CINH for the MCS to persist
through, and 3) models have trended the primary convergence zone
associated with LLJ further S and removed from the approaching
MCS. On the flip side, IF the MCS can persist into south central
Neb., model depict a significant reservoir of strong MUCAPE for
the MCS to work with, in the midst of moderate to seasonably
strong deep layer shear of 35-45kt. Needless to say, confidence on
exact evolution remains pretty low. Would think the primary
concern locally would be dmg wind gusts up to 70mph given
expected storm mode, but strong shear would also support some
embedded supercells and associated large hail threat, as well.
PWAT values briefly incr to near 2" could also support some
locally hvy rn.
Tstm chcs will continue through the day on Sat, owing to continued
influence from deepening upper low, as well as moist low level
airmass beneath much cooler mid level temps and less capping. This
should allow for any breaks in rain/clouds to only promote
stronger instability and renewed iso-scat tstm development by
early aftn. In fact, some models prog aftn SBCAPEs of 1500-2000
J/kg with nearly 30kt of bulk shear, which could be just enough
for some marginally severe hail given seasonably low WBZ levels.
So overall, Sat could be a bit of washout for some, and can`t rule
out iso/transient strong/marginally severe storms capable of
brief bouts of nickel-quarter size hail. Should see gradually decr
instability and PoPs with time Sat eve into overnight.
Sun looks to be pick day of the weekend as current forecast is
dry. May eventually need a slgt chc PoP for E portions of CWA for
aftn, but regardless, overall tstm chcs appear much lower than
Sat and airmass will be pleasantly mild and less humid. Dry
conditions are forecast Mon-Tue before next chc for shwrs/tstms
arrives towards middle of next week as temps return to the 90s.
&&
.AVIATION...(For the 00Z KGRI/KEAR TAFS through 00Z Saturday)
Issued at 836 PM CDT Thu Jul 8 2021
Ceiling/visibility/precipitation:
High confidence in VFR ceiling/visibility through the period, with
the lowest clouds likely consisting of a possible scattered to
perhaps broken deck as low as around 12K ft, particularly late
tonight into Friday morning. That same late night/early morning
time frame also contains the main (albeit highly-uncertain) window
of opportunity for hit-or-miss thunderstorm activity in the area.
As a result, have maintained a basic "vicinity thunderstorm"
(VCTS) mention, but have confined it to the 08-12Z time frame as
this looks most favorable. Severe storms are not anticipated, but
should storms develop, suppose some gusty winds cannot be ruled
out. Please note that much better chances for thunderstorms
(potentially severe) look to arrive shortly beyond this current
valid period (Friday evening-overnight).
Winds (including low level wind shear/LLWS):
Surface winds will be strongest right away this evening, averaging
southerly around 15KT/gusts 20+KT. However, these slightly-breezy
southerlies will gradually back off through the late night/early
morning hours. Then by mid-day Friday, a period of fairly light
winds (mainly sustained under 10KT) will be established in the
vicinity of a slowly-southward-sinking front, resulting in wind
direction perhaps becoming variable for a time but likely more
easterly by mid-late afternoon.
As for low level wind shear this evening into early Friday morning,
have largely maintained the mention from previous issuances with
only minor tweaks. This latest rendition contains LLWS from
04-13Z, as speeds within roughly the lowest 1,500 ft. AGL will
accelerate to around 45KT from the south-southwest, setting up
around 30-35KT of overall shear magnitude between the surface and
this level.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...NONE.
KS...Heat Advisory from 1 PM to 8 PM CDT Friday for KSZ005>007-
017>019.
&&
$$
UPDATE...Pfannkuch
DISCUSSION...Thies
AVIATION...Pfannkuch
Area Forecast Discussion
National Weather Service Grand Rapids MI
923 PM EDT Thu Jul 8 2021
LATEST UPDATE...
Update
.SYNOPSIS...
Issued at 248 PM EDT Thu Jul 8 2021
- Some drying into Friday night
- Risk for Showers and Thunderstorms returning Sunday into next
week
&&
.UPDATE...
Issued at 923 PM EDT Thu Jul 8 2021
I have added scattered showers to our forecast for tonight, mostly
for areas south of Route 20 and east of US-131. The latest surface
analysis at 9 pm shows a surface trough from near MKG to Lansing.
There is surface wind convergence on this trough (shown nicely by
our MSAS analysis tool). Meanwhile at the mid to upper levels, on
the water vapor loop, it is clear that there is a series of
shortwaves moving across lower Michigan early tonight. The
combination of the surface trough, shortwaves and cold air aloft
associated with the digging upper level trough over our are
helping to cause the light showers we are seeing develop on radar
between Grand Rapids and Jackson. These showers will not amount to
much but since they are there it seem reasonable to put them in
the forecast. The HRRR is showing the area of showers slowly
sinking south with time this evening. The showers should be out of
this area by midnight or so.
&&
.DISCUSSION...(This evening through next Thursday)
Issued at 248 PM EDT Thu Jul 8 2021
- Some drying into Friday night
An area of high pressure will build in from the northwest into
Friday. North to northwest winds ahead of this feature will
advect in a drier airmass. This will support the clouds breaking
up. Visible satellite imagery shows this trend underway around
Grand Rapids and Muskegon and points upstream. This drier airmass
will support lower than normal temperatures at night. Bufkit RH
overviews suggest we could see some diurnal clouds developing on
Friday...but they will likely be scattered to broken. Mid level
moisture starts to increase on Saturday so clouds may thicken up
then.
- Risk for Showers and Thunderstorms returning Sunday into next
week
A mid level trough digs down from the northwest Sunday into Monday
with the feature expected to close off to the southwest of the CWA
on Monday. Considerable uncertainty exists where this feature
closes off which will play a big role in terms of how much rain we
see. For now with steady height falls and increasing moisture...we
should see an increase in the shower and thunderstorm
activity...which we will feature in the forecast. Eventually for
the middle to end of next week this feature lifts through the CWA.
Given the moist axis that will exist out ahead of this
feature...above normal precipitation looks likely to occur.
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 730 PM EDT Thu Jul 8 2021
Expect low MVFR cigs more or less at all of our TAF sites through
the night tonight. As dry air moves in from the north the clouds
should thin out by mid morning Friday. Most of our TAF sites
should be mostly clear by mid afternoon.
It would not be out of the question there could be an isolated
shower this evening at any of the TAF sites but the risk is low
and even if it did happen the precipitation should be very light
and not impact visibilities.
&&
.MARINE...
Issued at 248 PM EDT Thu Jul 8 2021
The small craft advisory and beach hazard conditions will
continue into tonight as a the drier airmass advects in from the
northwest. Waves out in the mid part of the lake were around 5
feet at the buoy. Gust of around 20 knots are occurring as well.
The pressure gradient weakens later tonight into Friday...which
will support lowering of the winds and waves.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...Beach Hazards Statement until 5 AM EDT Friday for MIZ056-064-071.
LM...Small Craft Advisory until 5 AM EDT Friday for LMZ844>846.
&&
$$
UPDATE...WDM
SYNOPSIS...MJS
DISCUSSION...MJS
AVIATION...WDM
MARINE...MJS
Area Forecast Discussion
National Weather Service Gray ME
1100 PM EDT Thu Jul 8 2021
.SYNOPSIS...
Tropical Storm Elsa will approach the region tonight with
showers and thunderstorms overspreading the area. As this storm
passes just south of the region on Friday...very heavy rain is
expected across the region with flash flooding possible. Some
gusty winds are possible along the coast along with large
breaking waves. The remnants of the tropical storm will depart
the region Friday night and Saturday with seasonable
temperatures and dry weather expected this weekend.
&&
.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
1100 PM Update...
There are very few changes to the track or forecast philosophy
in terms of TC Elsa this evening (see latest updates from the
National Hurricane Center). The surface pressure within the
storm has dropped 4 mb in the last 6 hours and a portion of the
storm will continue to emerge over water late this evening.
Well ahead of this system, showers and isolated thunderstorms
continue to move northeast across the region. Much of the
precipitation weakened during the evening hours as it entered
New Hampshire and western Maine, however as we head into the
overnight period, more significant shower activity will enter
the region from southern New England per latest HRRR solution.
Made some minor adjustments to pops, dew points, winds and
lowered temperatures a tad per latest conditions and near term
mesoscale models. Temperatures will remain relatively steady
throughout the night and may actually rise over some areas.
Otherwise, very little in the way of changes to this updated
forecast package.
Prev Disc...
High pressure over Quebec will shift into the Canadian
Maritimes tonight while a stalled boundary over southern New
England lifts northward as a warm front. Warm frontal ascent
will be aided by dynamic lift from the right rear entrance of an
upper jet along with an approaching mid/upper level trough.
Some elevated instability along with warm cloud depths will aid
in rainfall efficiency with periods of moderate to heavy rain
expected overnight with embedded thunderstorms.
The axis of heaviest rainfall tonight still looks to remain to
our northwest with current QPF forecasts of around 1 inch in the
mountains to half an inch towards the coast before the remnants
of Elsa track through the area Friday morning. However, given
the convective nature of precipitation through this evening
locally heavier amounts are possible in thunderstorms. Lowering
ceilings and increasing low level moisture will lead to areas
of reduced visibility in fog and moderate to heavy rain. Lows
tonight will range from the 50s north to 60s south.
&&
.SHORT TERM /6 AM FRIDAY MORNING THROUGH FRIDAY NIGHT/...
Remnants of Tropical Storm Elsa Brings Heavy Rain to the
Region...
Tropical Storm Elsa will undergo extra-tropical transition as the
system crosses southern New England around mid-day tomorrow. The
primary threat with this system as it tracks into the Gulf of Maine
tomorrow afternoon will be very heavy rainfall across the region
focused along the foothills through the coast. Heavy rain is
expected to move into southern New Hampshire around 11 AM with
rainfall rates approaching 1 inch per hour. The system will
accelerate northeastward spreading heavy rain into southern
Maine between 12 pm to 2 pm with rainfall rates exceeding 1 inch
per hour. This heavy rain will continue to spread northeast
into the Capital District of Maine around 4 PM while the back
edge of the rain will be clearing through New Hampshire. Between
6 to 8 PM the system will be pulling away from the area as it
accelerates towards the Canadian Maritimes.
There is a strong likelihood that some areas will experience
rainfall rates of 1+ inches per hour for more than one hour.
This can be seen well in the 3 hour QPF products within the 12Z
HREF. The ensemble max 3 hour rainfall, which is a ballpark
worse case scenario, paints a broad area south of the mountains
with 3 hour max QPF in the 1.5 to 3 inch range with local
amounts to 4-5 inches. The ensemble mean 3 hour QPF paints a
more narrow area of 1 to 2 inches in 3 hours while the
probability matched mean 3 hour QPF hones in on the coast with 2
to 3 inches to locally 4 inches. Thus, the concern remains that
areas currently within the Flash Flood Watch could see upwards
of 3 inches of rain in a 3 hour period, which will exceed flash
flood guidance in some areas, particularly urban centers. The
one factor that will help mitigate flooding concerns is that the
remnants of Elsa are expected to accelerate through the area
minimizing the duration of heavy rainfall rates.
There remains good consensus within the 12Z model suite that the
heaviest rain from Elsa will stay south of the mountains with
no current changes to the Flash Flood Watch. Total QPF from
tonight through Friday night will range from 1.5 to 2 inches in
the mountains with locally high amounts along southeast facing
slopes. From the foothills to the coast total QPF will range
from 2 to 3.5 inches with local amounts approaching 4-5 inches.
Winds: Given the slight southward shift in the NHC track for
Elsa /and the consensus of the guidance/ the potential for
significant wind gusts is reduced. Current forecast package
depicts gusts remaining below 30mph along the coast throughout
the event as the direction remains from the northeast. A
northward change to storm track would bring the potential for a
period of stronger /30-40 mph gusts/ along the Midcoast for a
period late Friday morning through mid afternoon. However...this
is not currently the most likely outcome.
Elsa pulls away from the area Friday evening with rain ending by
sunset and relatively light northwest winds behind the system.
Relatively light winds and ample low level moisture will make
for areas fog Friday night.
&&
.LONG TERM /SATURDAY THROUGH THURSDAY/...
High Impact Weather Potential:
* Confidence too low to pinpoint severe weather potential...but
thunderstorm potential increases for the second half of the long
term forecast period /Tuesday-Thursday/.
* Building heat and humidity by Wednesday-Thursday of next week.
--Pattern and Implications--
Broad troughing over the eastern United States will open the period
but give way to a cutoff low over the Mid Mississippi Valley which
will allow high pressure over the central Atlantic to build west
into early next week with the mean flow trajectory over our area
backing from northwesterly to southwesterly. This should allow for
a moderating trend through the period with a seasonable summer
pattern unfolding. By the end of the period...the cutoff well to
our west ejects north and east...which will increase the potential
for unsettled weather to end the period.
--Daily Details--
Saturday - Sunday: High pressure builds over the region under
northwest flow aloft with PWATs falling below 1" on Saturday with
the high largely remaining in control through Sunday. Temperatures
look to be seasonable if not a bit below normal on
Saturday /mid-upper 70s/....warming a few degrees into Sunday.
Sunday night - Monday. As mid level low cuts off south of the Great
Lakes...northern stream shortwave passes north of the region Sunday
night into Monday...coaxing lift over stalled frontal boundary south
of our region. This will increase the potential for showers to
build north along the front with additional showers along the cold
front north of our region associated with the shortwave.
Temperatures on Monday look similar to Sunday with increased cloud
cover offsetting a slow increase in temps aloft. Certainly an
increase in humidity will occur over southern sections.
Tuesday - Wednesday: As the east coast ridge begins to build..the
potential exists for shower/storm activity in association with a
northward lifting warm front. Given building heights...forcing will
overall be weak so am not confident in significant convective
coverage. Certainly doesn/t look like a washout through this period
with the bigger story being increasing heat/humidity under warm
advection with high temperatures moving above seasonal norms by
Wednesday /lower 80s north - mid 80s south/.
Thursday: Guidance solutions diverge with their handling of the
cutoff low over the middle of the United States...but are in general
agreement that the ridge over our area will flatten with more
northern stream influence with the potential for shortwave energy in
the westerly flow aloft to bring a round of showers/storms to end
the forecast period. Any end to the warming trend will likely not
reach the region until after this forecast period ends...with
the potential for a hot/humid day on Thursday.
&&
.AVIATION /03Z FRIDAY THROUGH TUESDAY/...
Short Term...Conditions will deteriorate to IFR/LIFR tonight in
lowering cigs and reduced visibility in heavy rain and fog.
IFR/LIFR will continue through early Friday afternoon across the
area with improving conditions from SW to NE through Friday
evening. The remnants of Tropical Storm Elsa will track along
the Maine coast tomorrow afternoon possibly bringing periods of
wind shear with greatest chances occuring at KHIE and KRKD. Fog
may develop Friday night bringing restrictions again across much
of the area.
Long Term...VFR likely for Saturday-Sunday. Potential for
restrictions in SHRA and embedded TSRA Sunday night / Monday for
southern NH terminals up to PWM. This chance spreads north to
all terminals for Tuesday. Winds are expected to be light
through the period.
&&
.MARINE...
Short Term...Will hold on to gale watches this cycle given the
fact that the southward adjustment in Elsa/s track has reduced
the threat for gale force winds...even over the outer waters.
The current forecast would favor the need for SCAs...but will
allow the evening/overnight shift to make the final call in case
there is a northward adjustment in track.
Long Term...Lingering seas associated with Elsa will fall below
SCA levels during the day on Saturday with headline free
conditions likely on the waters beyond this through Tuesday.
&&
.HYDROLOGY...
NAEFS ensemble shows a 1000 kg /m/s Atmospheric river associated
with remnants of Tropical Storm Elsa moving into the region by 06Z
Friday. This is far above normal (near 30 year return based on
climatology) and more than sufficient moisture to produce
flooding. That said, research has consistently shown that the
AR is insufficient in an of itself to result in flooding. While
the abundant moisture is there, the flow remains from southwest
to northeast, up the coast, keeping it largely perpendicular to
the terrain. For the Whites, the main threat is training storms
as multiple rounds of precipitation move along this river. What
barriers might this moisture encounter to help ring it out?
Most straight forward is the Camden hills, which are easily
exposed to this flow direction, and a hot spot for flash
flooding along the coast. The largest barrier is of course the
White mountains and extending into western Maine. As the low
approaches on Friday winds will tend to curl around and into the
terrain, especially further east in Maine in the upper
Kennebec. Rainfall totals have generally increased in this
region with 2-3 inches now widespread. The third place to watch
for a focus of rainfall is along the coastal front. The
existing stationary front stretching from ME/NH border out into
the Gulf of Maine will try to lift northwards, and as the low
develops south of Block Island, the reinforcing NEly flow will
tend to strengthen the front. The combination of lifting along
the front and convergence as the wind decelerates off the water
makes the coastal corridor a place to watch for flooding as
well. This is nicely highlighted by both the HREF and the
Excessive Rainfall outlook. Here 4-5 inches is possible in a
narrow band.
River flooding: River flows are starting off well below average,
which helps to minimize the risk. Currently guidance from the
Northeast RFC shows the upper Pemi at Woodstock reaching action
stage, and certainly this is one of the flashier basins so the
threat seems reasonable if possibly a bit underdone. Further south
across southern NH the only potential focus for rainfall is along
the coastal boundary where conditions are driest and terrain flat
thus low chance for river issues there. Moving into Maine there are
a few potential areas to highlight. As noted above the upper
Kennebec basin will be a target of continued upslope flow, and the
4.2 inch flood guidance at Skowhegan is certainly within reach.
Along the coastal front the potential for 4-5 inches throws the
Presumpscot river at Westbrook into play for flooding.
Flash Flood Watch: While there are some isolated river flooding
possible, the main threat is for flash flooding with very
efficient rainfall processes, and thus a Flash Flood watch has
been issued. Rainfall rates in excess of 3"/hr are possible
within convective bands over the next few days, which will
quickly overwhelm even the driest conditions.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...Flash Flood Watch from 8 AM EDT Friday through Saturday
morning for MEZ012>014-018>028-033.
High Surf Advisory from 5 PM Friday to 11 AM EDT Saturday for
MEZ023>028.
NH...Flash Flood Watch through Friday evening for NHZ003>015.
High Surf Advisory from 5 PM Friday to 11 AM EDT Saturday for
NHZ014.
MARINE...Gale Watch from Friday afternoon through late Friday night for
ANZ150>152-154.
&&
$$
SYNOPSIS...
NEAR TERM...Cannon
SHORT TERM...Cannon
LONG TERM...Arnott
AVIATION...
MARINE...
HYDROLOGY...
Area Forecast Discussion
National Weather Service Houston/Galveston TX
714 PM CDT Thu Jul 8 2021
.AVIATION [00Z TAF Issuance]...
With the messy wet forecast continuing into tonight, have tried to
best time the bands of SHRA (isolated TSRAs) through the overnight
period...all strongly influenced by the latest HRRR guidance. And,
with that being said, aviation interests should continue to expect
a slew of amendments as conditions change throughout the night. As
we head into tomorrow afternoon, the weakening upper low and upper
ridge trying to build back into the region from the W/NW should be
heralding the onset of a slightly drier pattern. 41
&&
.PREV DISCUSSION... /ISSUED 239 PM CDT Thu Jul 8 2021/
..Locally Heavy Rain Possible over Parts of SE TX...
SHORT TERM [Tonight Through Friday Night]...
A broad upper level low over South Texas and a weak surface low in
roughly the same area of South Texas and a weak coastal trough of
low pressure will focus periods of showers and thunderstorms near
the middle and upper Texas coast through Friday. The surface low
retreats to the southwest by early Friday but the position and
orientation of the upper level feature will keep SE TX in a
favorable region for additional rain. The low level jet (LLJ)
increases to 30-35 knots between 03-06z tonight and the nose of the
jet targets the area around Matagorda Bay so feel the heaviest rain
should develop across Matagorda, Jackson and Wharton counties. SOme
of the models expand the precip into Harris but feel this is
overdone based on the orientation of the LLJ. The Flash Flood Watch
was expanded earlier to include Wharton and Ft Bend counties and
have some concern that Colorado county needs to be included as well.
Will advise the next shift and will monitor rainfall trends in that
area closely. Jet dynamics not looking as impressive as it did
yesterday but upper level winds still show a split across the region
but the speed max is no longer a significant player. As for rainfall
tonight, still looking for an additional 4 to 8 inches of rain in
the watch area with isolated totals between 10-12 inches. Further
north, 1 to 3 inches of rain possible over the central zones and
less than an inch over the northern zones. Significant river
flooding will be possible over the Lavaca Navidad, Tres Palacios and
San Bernard watersheds.
On Friday, locally heavy rain will probably persist over much of the
area during the morning but the upper low and surface low both
retreat to the W-SW and moisture levels begin to drop with PW values
falling to around 2.00 inches by mid-afternoon. Forecast soundings
show some drying in the 850-700 mb layer as well. There should be a
decrease in precipitation during the afternoon with drier conditions
to the E-NE and wetter to the W-SW. Upper level ridging will try to
expand into SE TX Friday night, but moisture trapped beneath the
ridge should allow for some isolated to scattered showers to
persist.
Clouds and rain cooled air should keep MaxT values a little below
climo but overnight lows should remain near climo for the next
couple of days. 43
LONG TERM [Saturday Through Thursday]...
"Here comes the sun, do do do do!" Saturday will essentially be our
transition day from the widespread coastal rains associated with the
previous low pressure system in South Texas to diurnally driven
scattered afternoon showers and thunderstorms that interact with the
seabreeze. This is due to the moisture transport decreasing as the
low dissipates with PW values finally dropping below 2" over the
weekend. As moisture fades away throughout the day on Saturday,
locations north of I-10 will be able to see more blue skies than
gray skies. This will be temporary though...global models are still
in consensus on an upper-level low embedded in a longwave trough
digging down into the Central Plains on Sunday. A corresponding
surface low will form in the Upper Midwest and attempt to push a
surface cold front into Southeast Texas. I say attempt because...it
won`t quite make it (sorry y`all). The GFS still takes the front the
furthest south of all of the solutions into the Brazos Valley before
it washes out. Meanwhile, the ECMWF washes the front out to the
north of the CWA. The positioning of the front is a key factor into
the rain chances on Sunday/Monday. With the consistency of the
models in keeping the front mostly north of the CWA, higher PoPs
will be relegated over our northern counties due to increased
moisture convergence with PW values approaching 2" and more
favorable jet mechanics. For now, going with 50-60% PoPs Sunday
through Monday afternoon.
Following Monday, we return back to our regularly scheduled
programming of afternoon showers and thunderstorms. With the
decreasing coverage of rain, temperatures will be able to climb back
into the 90s. Fortunately, model trends still indicate that high
temperatures will remain slightly below normal through next week
with highs in the low 90s inland and upper 80s closer to the coast.
Looking further ahead, there are no strong signals of a return to
upper-level ridging, so the below normal high temperature trend
appears that it will continue into next weekend. Overnight
temperatures will hold steady in the mid-to-upper 70s throughout
the forecast period, which is right around normal.
Batiste
HYDROLOGY...
Heavy rain is expected to develop tonight, especially over the SW
zones. If heavy rain does develop, there will likely be some
significant rises on the Lavaca Navidad, Tres Palacios, and San
Bernard watersheds. Based on current QPF forecasts, the Tres
Palacios could reach major flooding. Rainfall rates could reach 2-3
inches per hour with additional rainfall totals of 4 to 8 inches
possible in the Flash Flood Watch area. 43
&&
.PRELIMINARY POINT TEMPS/POPS...
College Station (CLL) 74 83 75 90 75 / 80 80 20 30 10
Houston (IAH) 74 82 76 90 76 / 90 80 40 50 10
Galveston (GLS) 78 84 82 89 80 / 90 70 40 50 20
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...High Rip Current Risk until 9 PM CDT this evening for the
following zones: Bolivar Peninsula...Brazoria Islands...
Galveston Island...Matagorda Islands.
Flash Flood Watch through Friday evening for the following
zones: Bolivar Peninsula...Brazoria Islands...Coastal
Brazoria...Coastal Galveston...Coastal Jackson...Coastal
Matagorda...Fort Bend...Galveston Island...Inland
Brazoria...Inland Galveston...Inland Jackson...Inland
Matagorda...Matagorda Islands...Wharton.
GM...Small Craft Advisory until 7 AM CDT Friday for the following
zones: Coastal waters from Freeport to Matagorda Ship
Channel TX out 20 NM...Coastal waters from High Island to
Freeport TX out 20 NM...Galveston Bay...Matagorda Bay...
Waters from Freeport to Matagorda Ship Channel TX from 20
to 60 NM...Waters from High Island to Freeport TX from 20
to 60 NM.
&&
$$
Discussion...99
Aviation/Marine...99
Area Forecast Discussion
National Weather Service North Platte NE
615 PM CDT Thu Jul 8 2021
.SHORT TERM...(This evening through Friday night)
Issued at 321 PM CDT Thu Jul 8 2021
A blend of the RAP, HRRR and HREF models is the basis for isolated
thunderstorm chances across wrn and ncntl Nebraska tonight. These
models suggest storm development across the Black Hills, Pine Ridge
and Cheyenne divide late this afternoon which would carry east this
evening and overnight. Winds aloft at h500mb should increase to 35
to 50 kts supporting isolated storms given the limited moisture-
PWAT around 1 inch. SPC suggested a marginal severe weather risk and
this is consistent with the strong winds aloft and limited moisture
across Nebraska. The better focus will be across SD where a warm
front will be positioned.
The warm front will drop south through wrn and ncntl Nebraska
tonight and the models are in very good agreement dropping the front
through swrn Nebraska by Friday morning. Wrn and ncntl Nebraska will
be post frontal Friday in a belt of easterlies. Moisture should pool
behind the front across the Panhandle and especially northwest
Nebraska where storm development appears probable by late afternoon.
There is little change in the winds aloft predicted by the models.
Winds at h500mb - h300mb should increase to 45 to 65kts by late
Friday afternoon and 0-6km/ 0-8km shear increases to 50kts, 60kts,
and perhaps even to 70kts depending on the timing of the arrival of
the stronger winds aloft. The NAM and GFS continue to show a rather
intense HP type storm/cluster developing across northwest Nebraska
late in the afternoon which moves east or southeast into and through
the Sandhills during the evening. PWAT has increased to near 1.25
inches by this time and given the very strong shear, the potential
for significant wind or hail is a concern as suggested by the SPC
severe weather outlook for Friday.
The POP forecast Friday and Friday night leans on the short term
model blend which places the best thunderstorm chances across
Sandhills as suggested by the NAM and GFS. Thunderstorm activity,
not necessarily severe, should continue overnight as heights aloft
fall with the approach of a developing upper level low.
.LONG TERM...(Saturday through Thursday)
Issued at 321 PM CDT Thu Jul 8 2021
The models are in very good agreement developing a h500mb cut-
off low across Iowa Saturday. The upper low may remain nearly
stationary across the Midwest through the weekend and into early
next week. Shower and thunderstorm chances continue Saturday but
given the cool temperatures in the 70s, the risk of severe weather
appears low.
The forecast is dry Sunday and Monday; the upper low across Iowa
stalls. Meanwhile, a strong subtropical high will remain anchored
across the Desert Southwest. The result is strong north winds aloft
and subsidence at the sfc across Nebraska. Winds aloft will become
west-northwest with the approach of a disturbance Tuesday.
The GFS and ECM are in good agreement suggesting the potential for
strong or perhaps severe thunderstorms Tuesday-Tuesday night. An
upper level disturbance will drop through the nrn Plains and this
should cause winds aloft at h500mb to increase to 35-45kts. Both
models suggest some sort of compact rain maker; presumably a severe
storm or cluster of storms affecting the Sandhills or ncntl
Nebraska. Chance POPs are in place Tuesday-Tuesday night for this
system.
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 615 PM CDT Thu Jul 8 2021
Isolated to scattered thunderstorms will traverse the forecast
area this evening and tonight. VFR is primarily expected, although
brief drops in visby/cigs will accompany any storm that affects a
terminal. Most activity will have waned by 09/06z, then clear
conditions will run through Friday afternoon. Gusty south winds
this evening will lighten tonight, then transition to east for
tomorrow.
&&
.FIRE WEATHER...
Issued at 321 PM CDT Thu Jul 8 2021
The short term models or CAMS, continue to suggest intense daytime
heating across the Panhandle will cause isolated thunderstorm
development late this afternoon. These storms would move east into
wrn Nebraska this evening. Dry lightning fire starts are the
concern and the HRRR wind gust product suggests the potential for
gusty winds with the thunderstorm activity.
The potential for dry lightning will continue Friday evening as
intense storms develop across northwest Nebraska and the Sandhills.
Minimum afternoon less than 30 percent is expected along and west of
highway 61.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SHORT TERM...CDC
LONG TERM...CDC
AVIATION...Snively
FIRE WEATHER...CDC
Area Forecast Discussion...Updated Aviation
National Weather Service Saint Louis MO
654 PM CDT Thu Jul 8 2021
.UPDATE...
Issued at 612 PM CDT Thu Jul 8 2021
Post-cold frontal advection of drier air upon northwesterly low-
level flow has been slow and gradual into the CWA so far this
evening with dewpoints remaining in the upper 60s to low-70sF,
outside of northeastern MO and west-central IL. Advection of dry air
is only anticipated to weaken through the remainder of the evening
into overnight as an inverted surface pressure ridge settles
southeastward near the Mississippi River Valley. The resulting
combination of winds becoming light, residual boundary layer
moisture, and efficient radiational cooling from mostly clear skies
has increased concerns for at least patchy radiation fog development
overnight into Friday morning. Currently, fog appears most favored
in proximity to the Mississippi River near and south of the St.
Louis metro and into southeastern MO, where the overlap of greatest
boundary layer moisture and lightest winds is forecast. Dense fog
also cannot be ruled out, especially in river valleys.
Pfahler
&&
.SHORT TERM... (Through Late Friday Night)
Issued at 306 PM CDT Thu Jul 8 2021
A slow-moving cold front continues to drift southeast across parts
of Missouri and Illinois this afternoon. The front is expected to
stall late tonight near the Missouri/Arkansas border. The short
wave currently over the Montana/Saskatchewan border is forecast to
move southeast into the Upper Mississippi Valley by Friday
afternoon. This will attenuate the ridge back over the Great Plains
and deepen the trough over the eastern U.S. somewhat, and the Mid
Mississippi Valley will end up in deeper northwest flow. The next
short wave in line, which is now moving onshore over Washington and
Oregon, will begin coming into phase with the longwave over eastern
North America on Friday over the Great Plains. This will force low
level cyclogenesis over the Plains and turn the flow back to the
south across Arkansas, Texas, and Oklahoma. The southerly flow will
push the front back to the north as a warm front Friday afternoon.
Short range deterministic guidance as well as the HREF is in good
agreement that precip tonight will stay along and south of the cold
front, and current indications are that the front will be southeast
of our forecast area by 00Z. Will therefore continue the dry
forecast for tonight. By 18Z Friday guidance shows the front near a
line from Hannibal to St. Louis to Chester, with some CAMs
developing scattered convection as early as 21Z in the vicinity of
the front. Deterministic guidance shows SBCAPE in excess of 2000
J/Kg along and west of the Mississippi with 40+ kts of 0-6km shear.
This is more than enough shear/instability to support severe
thunderstorms during the afternoon, but the main severe threat will
likely come Friday evening as an area of convection which is likely
to develop over Iowa congeals into a line and rushes southeast.
Several CAMs show this QLCS moving into northeast Missouri after 02Z
Saturday, and this scenario looks very reasonable in conjunction
with the deterministic guidance. The RAP shows a ribbon of 2500+
J/Kg MUCAPE persisting through much of the night in the vicinity of
the Mississippi River to maintain storms. Initially, the storms
will pose a hail and wind threat, and then shift to more of a wind
threat...with a few tornadoes also possible.
Carney
.LONG TERM... (Saturday through Next Thursday)
Issued at 306 PM CDT Thu Jul 8 2021
The aforementioned second short wave digs through the Missouri
Valley into the Mississippi Valley Saturday into Sunday. The wave
becomes highly amplified as it comes into phase with the long wave
trough over eastern N. America, and then it cuts off over the
Midwest. Both the GFS and ECMWF keep this cut off low spinning over
the region through at least Tuesday morning. The GFS is a bit
faster filling in the low and moving it out Tuesday, but both models
keep a troughy pattern over the Midwest through Thursday. The end
result will be several rounds of showers and thunderstorms for
Saturday through Tuesday. Some locally heavy rain looks likely
Saturday and Sunday as well since P-Wats will be around 2 inches,
which is up near the 90th percentile according to the NAEFS. With
clouds and precip in the forecast, temperatures should be mild, with
highs Saturday in the low to mid 80s, and Sunday and Monday`s highs
will struggle to reach 80 in most locations. Should see a warmup as
the upper level low finally exits Tuesday into Wednesday.
Carney
&&
.AVIATION... (For the 00z TAFs through 00z Friday Evening)
Issued at 653 PM CDT Thu Jul 8 2021
Fog will be likely across portions of the area overnight into Friday
morning, with KSUS and KCPS the most favored terminals to be
impacted. As such, MVFR visibilities have been introduced, with
further temporary reduction to IFR flight conditions also possible
at KSUS.
Otherwise, predominantly dry and VFR flight conditions
should continue into Friday. A few thunderstorms could develop as
early as late Friday afternoon along a nearby warm front; however,
low confidence in occurrence precluded inclusion of thunderstorms
with this TAF issuance. The exception is KSTL`s extended TAF period
with VCTS portraying increasing thunderstorm chances through Friday
evening.
Pfahler
&&
.PRELIMINARY POINT TEMPS/POPS...
Saint Louis 68 89 71 84 / 0 40 80 80
Quincy 64 82 69 79 / 0 60 80 70
Columbia 66 89 72 83 / 0 40 60 80
Jefferson City 67 91 73 85 / 0 40 50 80
Salem 66 86 70 84 / 0 40 80 80
Farmington 67 89 70 87 / 5 40 50 70
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...None.
IL...None.
&&
$$
WFO LSX
Area Forecast Discussion
National Weather Service Memphis TN
856 PM CDT Thu Jul 8 2021
.UPDATE...
A line of showers and thunderstorms is moving southeast toward the
Memphis area. This activity has developed along a prefrontal
trough ahead of the main cold front. The front is moving into
northeast AR and the Bootheel at this time but isn`t expected to
progress much farther south. The evolution of the ongoing
convection is the main forecast question for tonight. We have seen
outflow boundaries extending farther from the updrafts,
indicating it is moving into a less favorable environment of
shear/instability balance. Some of the recent guidance (HRRR/RAP)
suggests this activity will eventually stall along the I-40
corridor. A 30 kt low-level jet is forecast to develop across the
area overnight and could assist in maintaining or redeveloping
convection along the prefrontal trough overnight.
This could result in some training of showers and thunderstorms
tonight. However, confidence isn`t all that high given the lack
of agreement in the short-term model solutions. The primary
concern would be localized heavy rainfall. PoPs/QPF were adjusted
accordingly for the tonight period. Only minor changes were
needed for other elements.
MJ
&&
.PREV DISCUSSION... /issued 254 PM CDT Thu Jul 8 2021/
Fairly progressive pattern for July as weak northwest flow across
the Northern Plains to the Ohio Valley is forcing boundaries to
push into our region. Currently a weak front is the focus for
convection occurring across southern MO/Northern AR. Expect this
area to sink mainly across northern portions of our service area
along with pop up storms almost anywhere before dying out later
this evening.
Little overall change in the flow into Saturday as convective
systems threaten north of the forecast area. They may creep into
the Mid-South along with diurnal storms that continue to pop up
almost anywhere.
The big change in the flow begins later Saturday into early next
week as an upper low develops across the mid-section of the country.
A strong chance for thunderstorms is expected on Sunday as a surface
front pushes across our area. This upper level system pulls out by
mid-week leaving a continuation of progressive westerlies across the
north tier of the US. The risk for diurnally forced storms will
still continue in the wake of the upper low.
Temperatures overall through the period will begin fairly typical,
except lowering to below normal levels under the influence of the
upper low, producing clouds and precipitation. Temperatures will
recover to more normal as the upper low lifts out.
Belles
&&
.AVIATION...
00Z TAF Set
VFR conditions expected through the period. Although, scattered
convection continues to fire up along a weak boundary. The
boundary will gradually sink south to the TN/MS border overnight.
Latest HRRR keeps showers developing in the vicinity of the front.
Will introduce VCTS wording at KMEM and KMKL through 3Z then
convert to VCSH after sunset through the overnight hours. Will
reintroduce VCTS wording at 19Z at KMEM, KMKL, and KJBR. Expect
most of the activity to stay north of KTUP, but did throw in a
VCSH during the afternoon. S-SW winds of 5-10 KTS expected through
the period. KJBR could see some higher speeds during the
afternoon hours.
KRM
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...None.
MO...None.
MS...None.
TN...None.
&&
$$
...Updated Aviation Forecast Discussion...
.DISCUSSION...
Issued at 325 PM CDT Thu Jul 8 2021
Bottom line: some isolated strong/severe storms are possible
tonight along NE/SD border. Greater severe weather threat will be
sometime Friday afternoon/night, though lots of questions remain
on how things will pan out so overall forecast confidence is on
the lower side.
Clouds and even a few showers associated with a weak shortwave
sliding southeastward stuck around a little longer than planned
today which held temperatures down a few degrees. 3 PM readings
across the area were generally in the mid 70s to lower 80s.
Otherwise, of note in water vapor imagery were the upper level
high over the Desert Southwest along with a pair of
shortwaves...one along the Montana/Canada border and another just
coming onshore in the Pacific Northwest...that will play large
roles in our weather Friday into the weekend. Also playing a large
role will be a surface warm front currently analyzed from
northwest Nebraska south/southeastward into south-central Kansas.
The general idea heading into tonight is that the surface
boundary will lift northward while a low level jet ramps up and
leads to thunderstorm initiation somewhere near/along the NE/SD
border late this evening. Storms are unlikely to be surface-based
given timing, but a decent amount of shear and instability could
allow for some organized storms with large hail and perhaps some
gusty winds.
Storms will push southeastward through the early morning hours
Friday, with additional development expected across southeast SD,
southern MN, and into IA as the aforementioned MT/Canada shortwave
slides through. Strength of these storms (and associated cold
pools), as well as exact location will play a key role in where
the warm front (and greater severe weather threat) sets up during
the day Friday. In general, would think that cool outflow would
hold the warm front farther southwest than depicted in much of the
guidance. In addition, latest RAP guidance suggests fairly strong
isentropic ascent continuing in the warm sector through at least
mid-day, leading to cloud cover at the very least, and possibly
some additional showers and storms which most CAMs are suggesting.
Should these pan out, instability could be limited a bit and an
already expected stout cap could be that much stronger. They could
also help from a temperature standpoint, as mid to upper 90s are
currently forecast for portions of southeast Nebraska (though
dewpoints in the upper 60s to lower 70s will still make it feel
pretty uncomfortable).
On the other hand, if these warm sector storms don`t occur, or
clear out earlier in the day, MLCAPE values could approach 4000
J/kg per latest RAP guidance and the cap could erode a bit,
allowing storm development near the warm front. Should this
happen, supercells capable of all severe weather threats would be
possible, owing to the aforementioned instability and looping
hodographs in vicinity of the front, especially as the low level
jet ramps up by early evening. While this scenario would need a
lot of things to come together just right, it`s not completely out
of the question. However, the more likely scenario is that we
wait for some energy associated with the Pacific NW shortwave to
approach the area and assist with storm initiation in western
NE/SD. General idea is that those would eventually congeal to form
an MCS (or multiple) and slide through the area overnight,
bringing mainly a damaging wind and locally heavy rain threat. So
again, lots of questions remain, even being just 1 day out, but
the potential is definitely there for some impactful weather
heading into the weekend.
While the severe weather threat should exit the area by the early
morning hours on Saturday, expect showers and some storms to
linger in the area through the day as troughing continues to dig
into the Lower Missouri River Valley. Eventually expect a cutoff
low to form, the track of which will determine our weather for
Sunday into early next week. Should it hang around the area for a
while, would expect continued lingering showers and a few storms
Sunday and possibly into Monday...at the very least would expect
more cloud cover. As a result, daily highs will be in the 70s and
lower 80s, with the coolest day being Saturday. Still quite a bit
of spread between various ensemble members regarding timing and
track, however, so low confidence in how it`ll pan out. Eventually
expect the troughing/low to push off into the Great Lakes region,
allowing us to gradually warm back into the upper 80s and lower
90s by Tuesday or Wednesday. Also some hints at another shortwave
trough and associated precip sliding through sometime mid-week,
but lots of spread on exact timing, with solutions depicting
anything from Tuesday through Thursday.
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 628 PM CDT Thu Jul 8 2021
VFR conditions are forecast throughout the period. winds will be
veering from south-southeast to northwest throughout the day on
Friday. Some thunderstorms are possible near KOFK after 0600Z,
KOMA after 1000Z and KLNK after 1200Z. Some brief MVFR conditions
may impact KOMA, KOK, and KLNK if a storm moves right across the
field.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...None.
IA...None.
&&
$$
DISCUSSION...CA
AVIATION...Smith
Area Forecast Discussion
National Weather Service San Angelo TX
612 PM CDT Thu Jul 8 2021
...New AVIATION...
.SHORT TERM...
(This evening through Friday)
Issued at 111 PM CDT Thu Jul 8 2021
Visible satellite imagery this afternoon shows a nice field of
scattered cumulus having developed across West Central Texas.
However, RAP forecast soundings indicate that there will be enough
convective inhibition and subsidence from the expanding and
strengthening upper level ridge across the Southwest CONUS to
inhibit shower/thunderstorm development this afternoon, except for
possibly one or two isolated cells. With the stronger upper level
ridge and warming of the 850 mb thermal ridge, temperatures as of
1 pm are at least a few degrees warmer than 24 hours ago. Expect
highs today a few degrees warmer than yesterday, with highs in the
86-92 degree range.
Low clouds are likely to develop across the region from southeast
to northwest tonight through the early morning hours Friday
morning as a short-wave disturbance rotates into the Hill Country
around a mostly stationary upper low over South Texas. This
disturbance may also bring some isolated to scattered showers and
thunderstorms to the I-10 corridor and Northwest Hill Country late
tonight through Friday afternoon. With the increase in cloud cover
brought about by this disturbance and the associated enhanced,
moist easterly to southeasterly flow, expect slightly cooler
temperatures (highs in the 84-90 degree range) Friday despite the
stronger 500 mb ridge aloft. Meanwhile, lows tonight will be mild
once again, and perhaps a little warmer than last night due to the
aforementioned clouds/moisture (lows in the upper 60s/low 70s).
&&
.LONG TERM...
(Friday night through next Thursday)
Issued at 158 PM CDT Thu Jul 8 2021
Other than an isolated thunderstorm across the I-10 corridor, high
pressure will largely keep scattered thunderstorms from developing through
Saturday. However, a low pressure system moving across the Great
Plains will swing a cold front into the region on Sunday. This
will add support for additional thunderstorms to develop across
all of West Central Texas on Sunday and Sunday night. Highs will
likely remain in the upper 80s to middle 90s.
&&
.AVIATION...
(00Z TAFS)
Issued at 612 PM CDT Thu Jul 8 2021
MVFR conditions developing after midnight, lowering to IFR around
sunrise. IFR to MVFR ceilings will persist through at least
midday at far southern terminals. A few showers are also possible
tomorrow afternoon for these locations.
&&
.PRELIMINARY POINT TEMPS/POPS...
Abilene 69 88 72 92 / 0 5 5 5
San Angelo 69 88 72 92 / 0 10 10 10
Junction 70 84 72 89 / 10 40 30 20
Brownwood 70 86 73 92 / 5 10 10 10
Sweetwater 69 88 71 91 / 0 0 0 5
Ozona 68 87 71 89 / 5 20 20 10
&&
.SJT WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SHORT TERM...SJH
LONG TERM....41
AVIATION...SK