Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 07/26/18
Area Forecast Discussion
National Weather Service La Crosse WI
1058 PM CDT Wed Jul 25 2018
.SHORT TERM...(This afternoon through Thursday)
Issued at 214 PM CDT Wed Jul 25 2018
Main concern remains potential for strong to severe storms across
much of the forecast area into this evening. An early afternoon look
at satellite/radar/obs showed an area of showers with occasional
thunder associated with a weak shortwave moving into southeast
Minnesota. A cold front was draped northeast to southwest across
central Minnesota and will likely serve as the main focus of
convection this afternoon/evening, though still not a lot of
confidence on how everything will play out. The general idea is that
the front will approach from the northwest, and with increasing
moisture transport ahead of the front by late afternoon, storms are
expected to develop just northwest of the front. In addition, a
stronger shortwave will move across central Minnesota into northern
Wisconsin this evening, providing a little bit better forcing in
these areas.
Despite a fair amount of instability, the showers moving into
southeast Minnesota were quickly dissipating due to very little
forcing. With this lack of showers to use up the instability,
combined with a little less cloud cover than expected, could see a
bit more instability than first thought (SBCAPE approaching 2000
J/kg). However, the strongest deep layer shear looks to remain
mainly behind the front/storms, though could see a very narrow
corridor right along the front where the best shear overlaps the
instability. This would be the most favorable area for any
organized storms and severe weather.
Looking at severe weather types, thinking wind and maybe hail will
be the greatest threats. Despite the strongest deep shear being
behind the storms, 0-3 km shear looks decent, with around 25 kts or
so ahead of the front, with much of it being line-perpendicular. In
addition, forecast soundings show deep mixing in the lower levels,
though the RAP does seem a bit overdone with this, as we are not
seeing any wind gusts over 25 kts like it suggests with its winds at
the top of the mixed layer. Mid-level lapse rates near 6.5 C/km and
the aforementioned instability also suggest a hail threat, but
thinking the signals for wind are a little stronger. Unlike previous
severe weather events, heavy rain does not appear to be a major
threat, with precipitable water values in the 1.3-1.5 inch range and
shallower warm cloud depths (which are also more favorable for hail)
in the 3-3.5 km range. Bottom line, thinking the convection will be
in a somewhat unorganized, broken line along the front with a few
cells/bowing segments producing strong to damaging winds and hail.
The front and storms should be out of the area by midnight, with a
breezy, cool day on tap for Thursday with 20+ mph wind gusts out of
the northwest. High temperatures look to be in the mid 60s to mid
70s. In addition, with cyclonic flow remaining in the area, could
see a few "popcorn" light showers, especially if we manage to get a
bit of sunshine to peek through the clouds.
.LONG TERM...(Thursday night through Wednesday)
Issued at 214 PM CDT Wed Jul 25 2018
For Thursday night thru Saturday night: main fcst concerns are the
cooler, below normal temperatures thru the period.
25.12z model runs in good agreement for NW flow aloft to continue
developing over the Upper Midwest Thu night/Fri, with second
shortwave trough/energy to dig in and help carve out even deeper
troughing aloft over the region by Sat/Sat night. Confidence is good
for Thu night thru Sat night to be a seasonably cool period across
the area.
A cool low level airmass settles over the area Thu night but NW
gradient winds looking to remain in the 5-10mph range to keep BL
stirred and lows from dropping too far, even after the seasonably
chilly temps on Thu. Even so, consensus lows in the low-mid 50s are
going to feel cool. Weak sfc high pressure to slide over the area
Fri, for much lighter winds than Thu. Highs to recover a bit Fri
without the brisk NW winds and cold advection, with mixed 925mb
temps supporting highs in the 70s. With lighter winds Fri night will
have to watch for the potential of late night valley fog along with
lows in the normally colder low laying areas dipping into the 40s.
Lower level trough and some thermo-dynamic forcing to accompany the
round of shortwave energy to move into/ across the region later
Sat/Sat night. Some small, mainly SHRA chances and mainly west of
the MS river later Sat/Sat night, along with highs/lows a category
or 2 below normal, OK for now.
For Sunday thru Wednesday (days 4 to 7): main fcst concerns this
period are some SHRA/TSRA chances Sun/Mon and continued below normal
temps thru Tue.
Medium range model runs of 25.00z/25.12z in rather good agreement
for an anomalous cold mid level troughing to settle over the
central/ eastern CONUS Sun/Mon then persist into the middle of next
week. NAEFS std deviations of -2 to -3 on 500mb hgts/temps Sun-Tue
with some slow modification/warming by Wed. Fcst confidences is
average for precip chances this period but good for temps to remain
below normal, at least thru Tue.
Some signal for a lower level low/trough to swing thru the region
under the deep, cold cyclonic flow of the mid level troughing
Sun/Mon. This along with potential for plentiful lower level
moisture in the circulation. Consensus 20-40% SHRA/TSRA chances
mainly Sun/Mon afternoons reasonable at this point. More of a signal
for lower level high pressure, and drying to build in for Tue/Wed.
Some more southerly lower level flow and warm advection even progged
to return on Wed. Until then, general northerly flow and below
normal 925-500mb temps to keep highs/lows for Sun thru at least Tue
night in the below normal range as July comes to an end and the
calendar turns to Aug.
&&
.AVIATION...(For the 06Z TAFS through 06Z Thursday night)
Issued at 1058 PM CDT Wed Jul 25 2018
Showers and storms have exited the area as a cold front has pushed
east of LSE and RST, with clearing skies noted. Much cooler air
filtering into the region behind that front will allow for a
rather rapid expansion of stratocumulus clouds Thursday morning
and afternoon, with primarily VFR ceilings expected but some low
end chance RST could see brief intervals of MVFR conditions.
Winds will become a bit gusty from the northwest during the day
Thursday, with gusts either side of 20 knots expected for all
areas. In addition, there is a risk for isolated showers to
develop during the afternoon hours, though will refrain from any
mention at this point for the TAF sites given uncertainty.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
IA...None.
&&
$$
SHORT TERM...CA
LONG TERM...RRS
AVIATION...Lawrence
Area Forecast Discussion
National Weather Service Burlington VT
1055 PM EDT Wed Jul 25 2018
.SYNOPSIS...
Welcomed rainfall will continue tonight as deep moisture shifts
east across the area. Dry weather returns by tomorrow before
additional showers and a few thunderstorms return for Friday
into Saturday. Temperatures will remain seasonably mild to warm
through the next week with no excessive heat expected.
&&
.NEAR TERM /THROUGH THURSDAY NIGHT/...
As of 1054 PM EDT Wednesday... Moderate to heavy showers are
over the Champlain Valley at the moment with the trough
positioned just to the west. Most lightning has ceased with this
line of showers and it has begun to slowly weaken. This has
been depicted well in hi-res guidance and this activity will
continue to gradually weaken as the front pushes east and
interacts with an advancing shortwave moving northward along the
southern New England Coast. Latest guidance suggests this will
move through a little faster and be positioned a little further
east. Have adjusted temperatures and PoPs for the latest trends,
mainly to clear out New York a little faster and then to allow
rain to move out a little faster Thursday morning. All else
remains in excellent shape. Have a great night.
.PREVIOUS DISCUSSION...
The forecast remains largely on track for this evening into
tonight. We continue to watch a deep subtropical moisture plume
oriented from southern Quebec southward into the coastal Mid-
Atlantic and southeastern seaboard this afternoon. This axis
lies on the western periphery of pronounced western Atlantic
ridging centered near 40N/- 60W which has been semi-stationary
over the past 48 hours. Within this band scattered to numerous
showers continue, though in the immediate Champlain Valley we`ve
largely missed the activity so far. This is illustrated quite
well in some of the higher-res model output, most notably in the
NAM 3km and HRRR and as such have leaned heavily toward their
solutions over the next 12 hours accordingly. This will keep
steadiest/heaviest showers mainly across northern NY through
early evening before a gradual shift east into VT is expected
later this evening into the overnight hours as a weak shortwave
feature tracks north- northeast through southeastern New
England. Instability is rather meager and with near moist-
adiabatic lapse rates only an outside shot of thunder is
expected and mainly through midnight or so. I`ll also maintain
locally heavy rainfall wording given the aforementioned moist
airmass, though to be honest, outside a few stripes of heavier
rainfall model-blended QPF has been grossly overdone in most
spots for this event so far. To maintain temporal and spatial
continuity with our prior forecast I leaned toward a blended
solution of our official forecast and most recent WPC guidance
for QPF though with a 50% reduction factor given this bias. This
will support additional basin- averaged rainfall of a quarter
to half inch from the eastern slopes of the Adirondacks eastward
overnight, though with full realization that there will be a
few stripes of heavier totals from 0.75 to 1.5 inches in more
persistent shower bands. Lows tonight to remain quite mild under
continued light southerly flow - mainly in the 60s to locally
near 70 in mildest valley locales.
Any morning rainfall across eastern counties then edges eastward
over time on Thursday leaving a largely dry afternoon under
increasing partial sunshine from the Champlain Valley westbound.
Model-averaged 925 mb temperatures rebound into the 20-24C range in
these areas by late afternoon and with decent boundary layer mixing
to near 850 mb high temperatures were raised several degrees (i.e. a
spot high of 88F at KBTV and 85F at KMSS). Further east, clouds will
likely hang on through at least mid-morning to early afternoon,
tempering readings slightly (upper 70s to lower 80s).
Then mainly quiet by Thursday night as we remain under broad
southwesterly flow ahead of an approaching surface trough to our
west. Generally advertised a broad increase in clouds by later at
night with chances of a few showers across western counties toward
sunrise as this feature approaches. Lows remain mild in the 60s.
&&
.SHORT TERM /FRIDAY THROUGH FRIDAY NIGHT/...
As of 324 AM EDT Wednesday...Highlight for the period continues
to point towards the convective potential on Friday as a
secondary cold front swings through the region. Should be a
fairly mild and muggy night ahead of the boundary Thursday night
with lows widespread in the 60s and little dewpoint spread.
Come 12Z Friday morning the front looks to be on the BTV CWA
doorstep with showers developing across northern New York during
the mid-morning hours. Increasing clouds and precipitation
should keep instability at a minimum here, but eastward the
potential for some stronger storms to develop still looks
plausible with daytime surface heating aiding in SBCAPE`s
pushing over 1000 J/kg. This, combined with PWAT`s surging back
up over 1.5", decent upper jet dynamics and modest low level
shear certainly supports the idea of scattered to numerous
showers and thunderstorms developing through the afternoon from
the Adirondacks eastward with the potential for a few strong to
locally severe storms.
Any convective activity wanes Friday night as the front shifts east
of the forecast area and surface instability weakens with the loss
of insolational heating. A few lingering showers are possible across
eastern Vermont through midnight, but thereafter drier conditions
are expected for the remainder of the night.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
As of 324 AM EDT Wednesday...Drier and more comfortable
conditions are still expected for the upcoming weekend as
surface high pressure builds into the region. An upper level
trough lifting northeast through southern Canada could provide
enough energy to spark a few isolated showers Saturday, but for
most areas dry conditions are expected through the weekend under
partly cloudy skies. Temperatures will be right around seasonal
normals - highs in the mid 70s to low 80s, and lows in the mid
50s to low 60s with comfortable humidity expected as well.
Unfortunately this pattern change will be only brief as the
upper trough to our west and Bermuda high to our southeast both
look to become reestablished, with the return of a deep tropical
southwest flow across the majority of the East Coast.
&&
.AVIATION /03Z THURSDAY THROUGH MONDAY/...
Through 00Z Friday...band of moderate to heavy showers along
with isolated tsra is slowly pushing across northern NY and
reaching the Champlain Valley at this time. Primarily VFR across
VT right now, but as the precipitation overspreads the area,
expecting MVFR conditions (both ceiling and visibility) to
develop. Could be brief IFR visibilities, and in fact SLK
briefly dropped to 1/4sm when the heavy rain moved over. In
general looking at the heaviest of the rains to effect PBG/BTV
through 04z, RUT 02-06z, MPV 03-07z. Indications are that light
showers will continue for much of the night with even the threat
beyond 13z for many of the VT terminals. Want to note that some
guidance is indicating fog to form after 05z across parts of
the St Lawrence Valley and into the `Dacks, with LIFR for MSS
and SLK. If the clouds do clear out, that is quite possible, but
at this point think enough clouds and a few showers around will
keep the potential for such fog to develop at a minimum. VFR
conditions will develop between 13-18z from west to east on
Thursday.
Outlook...
Thursday Night: VFR. Slight chance SHRA, Slight chance TSRA.
Friday: VFR. Chance SHRA, Chance TSRA.
Friday Night: VFR. Chance SHRA, Slight chance TSRA.
Saturday: Mainly VFR, with local MVFR possible. Chance SHRA.
Saturday Night: VFR. Slight chance SHRA.
Sunday: VFR. Slight chance SHRA.
Sunday Night: VFR. Slight chance SHRA.
Monday: VFR. Chance SHRA.
&&
.EQUIPMENT...
As of 345 PM EDT Wednesday...The KCXX radar continues to have
calibration issues and this is causing problems with dual-pol
derived precipitation. The dual- pol derived rainfall amounts
appear to be much greater than what is actually being observed.
The legacy rainfall products appear to be more reliable based on
observations. A technician visited the site yesterday and has
ordered replacement parts with the expectation that a more
thorough diagnosis will be performed later this week, weather
permitting.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...None.
NY...None.
&&
$$
SYNOPSIS...JMG
NEAR TERM...Haynes/JMG
SHORT TERM...Lahiff
LONG TERM...Lahiff
AVIATION...Nash
MARINE...JMG
EQUIPMENT...Team BTV
Area Forecast Discussion
National Weather Service Cheyenne WY
936 PM MDT Wed Jul 25 2018
.UPDATE...
Issued at 933 PM MDT Wed Jul 25 2018
Although several lines of thunderstorms are moving east southeast
across southeast wyoming and the southern NE panhandle late this
evening, the heavy rain threat is over for tonight with only brief
heavy rain possible. Cancelled the Flash Flood Watch near the
Colorado border. Will have to monitor Thursday and Friday for
another slight risk of flash flooding and the potential for more
strong to severe thunderstorms. Kept POP between 50 to 80 percent
through midnight, with the exception of the northern Nebraska
panhnadle.
&&
.SHORT TERM...(This evening through Thursday)
Issued at 300 PM MDT Wed Jul 25 2018
Conditions are coming together for a possible heavy rain/severe
thunderstorm event this afternoon and evening. Forecast challenges
deal with severe thunderstorm and heavy rain potential this
afternoon and tonight.
Currently...Water vapor imagery showing an upper level shortwave
located across central Wyoming this afternoon with a surface
boundary located from Alliance to Casper. Earlier boundary located
across southeast Colorado up to near Saratoga. Afternoon dewpoints
quite high with Cheyenne at 57F with low to mid 60s in the
Panhandle. Radar showing convection blossoming across Carbon and
Albany Counties this afternoon, being the closest to the upper
level shortwave. SPC Mesoanalysis page showing surface based CAPE
of 1500 to 1600 J/KG with bulk shear on the order of 45-50kts
across the Laramie Range and points east. CAPE forecasts continue
to rise to near 2500-3000 J/KG by 00Z.
Will continue with threat of severe convection this afternoon. Got
a report from the Summit just a few minutes ago that ponds are
full up there from thunderstorms yesterday, so decided to add the
Summit into the Flash Flood Watch this evening. Forecast soundings
after 00Z showing long/skinny CAPE profiles indicative of heavy
rain with PWATS close to 1.25 inches. Heaviest rainfall forecast
between 00Z and 06Z this evening.
Another round of heavy rain possible Thursday afternoon. SPC has
another Marginal Risk area identified, so conditions similar
Thursday afternoon to today. Later shifts will likely need to
issue another Flash Flood Watch for Thursday.
.LONG TERM...(Thursday night through Wednesday)
Issued at 300 PM MDT Wed Jul 25 2018
Perhaps our biggest day severe/heavy rain wise will be Friday as
models show surface boundary shifting east into Nebraska. Some
differences in forecast solutions seen as GFS thrusts the font
into North Plattes area. ECMWF much further west in the Panhandle
with heavy rainfall covering much of the Panhandle. Should the
ECMWF solution come true, we could be looking at widespread
severe weather in the Panhandle and parts of extreme southeast
Wyoming. Would think the ECMWF has a better handle on the
placement of the surface boundary and have kept PoPs pretty high
based on this model output. Front backs to the west on the ECMWF
Friday night into Saturday as an upper shortwave tracks across
western Nebraska Friday evening. SPC has already identified a
Slight Risk area for the Panhandle in their Day 3 outlook, so
confidence fairly high on the ECMWF solution.
Widespread afternoon/evening showers and thunderstorms expected
again Saturday and Sunday as the surface boundary stalls along
the Laramie Range. Both days could see severe thunderstorms as
upper level disturbances ride over the front both days.
Drier weather still expected from Monday on into the rest of next
week. Four corners high still forecast to shift west into the
southern Nevada area, cutting off monsoonal moisture flow into
Wyoming.
&&
.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
Issued at 527 PM MDT Wed Jul 25 2018
Possibly another round of storms near KCYS over the next couple
hours. Thinking mostly showers though as latest HRRR does show
another area developing this evening and becoming fairly
widespread. Next chance for thunderstorms will occur Thursday
afternoon as daytime heating produces instability.
&&
.FIRE WEATHER...
Issued at 300 PM MDT Wed Jul 25 2018
Minimal fire weather concerns over the next 3-4 days as monsoonal
moisture remains in place and widespread wetting rains are
expected. Afternoon humidity expected well above critical levels
with good to excellent overnight recoveries. Heavy rainfall
expected along the Interstate 80 corridor from Sidney to Laramie
could lead to possibility of flash flooding this afternoon and
again Thursday. Drier weather expected to return Monday and
continue into most of next week.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...None.
NE...None.
&&
$$
UPDATE...TJT
SHORT TERM...GCC
LONG TERM...GCC
AVIATION...GCC
FIRE WEATHER...GCC
AREA FORECAST DISCUSSION
National Weather Service Eureka CA
252 PM PDT Wed Jul 25 2018
.SYNOPSIS...Hot and dry conditions will continue across inland
areas for the foreseeable future, with typical cool and
periodically cloudy conditions near the coast.
&&
.DISCUSSION...Given the complete lack of cumulus development
across our interior mountains, suspect we will not see any shower
or thunderstorm development this afternoon or this evening. Weak
cu field and hi-res model guidance continue to point toward
isolated storms in eastern Siskiyou county, to the northeast of
our forecast area. Meanwhile, the low-level wind flow continues to
carry most of the smoke from the Carr and Natchez fires off to
the northeast of Trinity and Del Norte county as well. HRRR smoke
model does indicate some smoke aloft trying to push southward
across Del Norte and western Humboldt county on Friday, which
could happen with the increasing northerly flow. Did not reflect
this in the forecast yet, but this may be something we add if we
begin to see the smoke begin drifting south/southwestward.
Otherwise, the forecast message remains largely unchanged, with
very seasonable conditions albeit with above average temperatures
inland. Heat advisories will continue for interior areas with
elevated risk of heat-related illnesses continuing, especially for
those groups sensitive to hot temperatures. Considered extending
the heat advisory into Friday, but there will be some slightly
lower high temperatures that day as an upper-level trough drops
across the Pacific Northwest, putting a slight dent in the
dominant upper-level high pressure system across the southwestern
United States. More noticeable lowering of high temperatures will
occur this weekend, but interior valleys will still reach into the
upper 90s in many locales.
At the coast, the waxing and waning of coastal stratus will
largely continue, with much cooler conditions compared to inland
areas. Expect sunshine away from the beaches still during the
afternoon hours. Some increasing in northerly winds over the
coastal waters may help to increase the duration of clearer skies
around Shelter Cover, Crescent City, and much of the Mendocino
coast by Friday and heading into the weekend.
&&
.AVIATION...Coastal conditions have been quite consistent over
the last few days. Marine stratus continued to blanket the coastal
waters and near shore airports...including ACV and CEC. These air
terminals were frequently at or below the airfield minimums as
CIG/VIS dropped into LIFR/IFR today. A coastal shear zone produced
BINOVC just offshore, although onshore flow kept low CIGS mostly
piled up over the main air terminals. Expect to see deteriorating
of CIG/VIS by early evening once again as the cool moist air rolls
back over the coastal shores. Profiler continued to show a fairly
shallow but persistent marine layer as the inversion appears
strong and nearly static. Flying conditions over inland mountain
and valley areas will continue with VFR. /TA
&&
.MARINE...Light to moderate northerly breezes will continue
tonight. Northerly winds will begin to ramp up tomorrow and
especially for Friday and the weekend near and south of Cape
Mendocino. Seas will remain fairly low until the winds begin
picking up, still dominated by short period northerly wind waves.
Mixed longer period southerly swell will start lowering tonight.
The combination of short period northerly wind waves and long
period southerly swell will create uncomfortable boating
conditions in some shoaling areas. Patches of fog may also reduce
vsbys to 1/4SM or less, especially nearshore and through harbor
entrances.
&&
.BEACHES HAZARDS...A longer-period southerly swell will continue
to impact northwest California beaches through the late afternoon
hours, in particular the south facing beaches like South Beach,
Shelter Cove, and Point Arena. This south swell will generate
longer lulls between sets of larger waves. These larger sets of
waves can catch beach goers off guard. Beach goers should stay off
rocks and jetties and stay farther back from the ocean. All
indications are that the swell is lowering in period and in
amplitude, probably closer to 3 to 4 feet at 16 seconds, which
should reduce the threat of larger breaking waves. Will continue
the statements for the beaches and the coastal waters through 5 pm
this afternoon.
&&
.FIRE WEATHER...Little change to the forecast package this
afternoon as hot and dry conditions will persist through the rest
for the week, only easing slightly this weekend. Interior
temperatures will soar into the upper 90s to mid 100s during the
afternoon with some areas around Ukiah and along the Trinity
River peaking between 105 and 110. Overnight recoveries will
remain good in the valleys, but only moderate in upper elevations
within the thermal belt. Winds will remain mostly light and
heavily influenced by terrain, with perhaps slightly breezier
northerly winds in exposed areas during the afternoon hours.
&&
.EKA WATCHES/WARNINGS/ADVISORIES...
CA...Beach Hazards Statement until 5 PM PDT this afternoon for CAZ101-
103-104-109.
Heat Advisory until 11 PM PDT Thursday for CAZ107-108-110-111-
113.
NORTHWEST CALIFORNIA COASTAL WATERS...None.
&&
$$
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Area Forecast Discussion
National Weather Service Fort Worth TX
950 PM CDT Wed Jul 25 2018
.UPDATE...
The inherited forecast is in pretty good shape. Made some minor
tweaks to re-trend the near term hourly elements based on recent
observations, and to nudge sky cover upwards for the overnight
hours and into Thursday morning.
Convection is blossoming ahead of a cold front which bisects
Kansas from northeast to southwest at this hour. While additional
activity may develop into the Oklahoma/Texas Panhandles overnight,
none of this activity is expected to survive the trek across
Oklahoma as it encounters an increasingly dry and stable airmass.
This convection will, however, throw some additional mid and high
cloud cover our way, so nudged sky coverage up late tonight and
into Thursday. Several evening CAMs are showing some high-based
convection developing across our far western/northwestern counties
Thursday afternoon and evening, and recent RAP soundings do show
locales west of US-281 becoming uncapped as a modest increase in
surface dewpoints results in a few hundred J/kg of MLCAPE. Given
the surfeit of dry air present in the sub-cloud layer (under 10
kft), it seems unlikely much in the way of precipitation would
reach the ground unless more robust updrafts can be established.
For the time being, just added some silent 10% PoPs across this
portion of the CWA tomorrow afternoon. If a stray storm were to
develop here, an isolated downburst threat would exist with near
40 degree dewpoint depressions during peak heating.
Carlaw
&&
.AVIATION... /Issued 657 PM CDT Wed Jul 25 2018/
/00z TAFs/
Surface winds early this evening will generally be out of the
east-southeast, but will gradually veer to the south overnight
with speeds remaining under 8 kts or so. By Thursday morning,
winds may briefly come all the way around to the west-southwest
ahead of a weak cold front which will be dropping into Central
Oklahoma, but predominantly south winds should return during the
afternoon as mixing brings more southerly momentum down to the
surface.
Cloud cover around FL300 will increase late tonight and into
Thursday as anvil debris from upstream convection drifts across
North and Central Texas. Diurnal Cu with bases near FL080 will
also be a bit more prevalent Thursday afternoon as we mix into
moisture around 700 mb. Finally, there may be an outside
potential for some high-based convection to develop late Friday
afternoon/evening ahead of the aformentioned cold front, but a
very dry sub-cloud layer points to impacts mainly from turbulence
associated with evaporating precipitation.
Carlaw
&&
.SHORT TERM... /Issued 301 PM CDT Wed Jul 25 2018/
/Tonight/
Another shortwave trough will move out of the Central High Plains
tonight, bringing showers and thunderstorms to parts of the
Panhandle and Eastern New Mexico. Much like Tuesday night, North
Texas will only see a slight increase in high clouds overnight.
Lows tonight will fall into the 70s with a light south to
southeast wind.
79
&&
.LONG TERM... /Issued 301 PM CDT Wed Jul 25 2018/
/Thursday through Wednesday/
The upper ridge over the Desert Southwest will begin to deamplify
Thursday through the weekend while a strong upper trough and
associated cold front brings cooler and unsettled weather from the
Northern Rockies to the East Coast.
It will remain hot across North and Central Texas through the
weekend with highs mainly in the upper 90s to near 102 and lows
generally in the 70s. One notable change will be a slow but steady
increase in humidity as southerly winds return in response to a
deepening surface lee trough across the Central High Plains. The
increase in humidity and the approach of the cold front from the
north will also bring some low shower and thunderstorm chances
generally north of I-20 Thursday night through Sunday. We will
keep PoPs low since moisture will be shallow. However, any storms
that do manage to develop will be capable of gusty downburst
winds.
Relatively cool and dry air is progged to build southward across
the Central Plains Sunday while an upper trough deepens across the
Great Lakes and the Midwest. This airmass will move into North
Texas Sunday and make it all the way to the Upper Texas Coast by
Monday night. Showers and thunderstorms will accompany the cold
front with the best rain/storm chances Sunday night and Monday.
Precipitation chances will end by Tuesday, but dry and relatively
cool air will remain in place through the middle of next week
with highs generally in the lower 90s and lows ranging from the
upper 60s to the middle 70s.
The threat for new fire starts will remain high through the
weekend due to hot/dry weather and abundant dry vegetation. Wind
speeds should remain generally less than 15 mph through the end of
the week, but it will become breezy on Saturday which will
elevate the fire threat even more. The fire threat should decrease
temporarily early next week due to cooler temperatures and the
chance for widespread wetting rainfall.
79
&&
.PRELIMINARY POINT TEMPS/POPS...
Dallas-Ft. Worth 78 102 80 99 79 / 0 0 5 10 20
Waco 75 102 76 102 77 / 0 0 0 0 5
Paris 73 100 75 94 74 / 0 0 10 30 20
Denton 74 102 77 98 77 / 0 0 5 10 20
McKinney 74 101 77 98 76 / 0 0 5 10 20
Dallas 80 102 82 100 80 / 0 0 5 10 20
Terrell 74 102 77 100 77 / 0 0 5 10 20
Corsicana 75 102 76 101 77 / 0 0 0 5 5
Temple 74 102 74 101 75 / 0 0 0 0 0
Mineral Wells 73 102 75 99 75 / 0 0 5 10 10
&&
.FWD WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
90/25
Area Forecast Discussion
National Weather Service Goodland KS
544 PM MDT Wed Jul 25 2018
.SHORT TERM...(This evening through Thursday)
Issued at 115 PM MDT Wed Jul 25 2018
A fairly high impact severe weather event is expected across much
of the area this afternoon and tonight. It will occur in two
rounds. The first round will develop along a cold front/outflow
boundary apparent on radar, which has stalled out roughly along
Interstate 70. Once the cap breaks, the environment will be
characterized by strong instability along/north of the front (up
to 3500 j/kg) and moderate to strong instability south of the
front, with deep layer shear of around 40kts. Upper forcing is
rather weak, with only the hint of shortwave trough coming over
the western ridge. Nonetheless, the frontal boundary should be
sufficient for convective initiation. Initial storms will be
capable of producing very large hail, damaging winds and perhaps
an isolated tornado near the surface boundary. Storm motions are
southeast at around 15kts with right movers more south also at
15kts, suggesting a limited flash flood threat, at least
initially. However, a second round of thunderstorms will develop
in the post frontal upslope regime in northeast Colorado and move
across most of the area this evening. These storms will probably
congeal into an MCS capable of producing widespread damaging wind
gusts and embedded storms capable of producing large hail. The
complex will be moving rather slowly and could continue well into
the overnight hours. With heavy rain from the complex occurring
over areas that may receive heavy rain from the afternoon storms,
issued a Flash Flood Watch, with good support from the ensemble
HRRR which shows storm total accumulations of 1-2 inches over much
of the Flash Flood Watch area through tonight.
After any lingering storms dissipate Thursday morning, expecting a
less active day. Surface front will be pushed well to the south by
the convection, leaving the local area with a broad, southeasterly
surface flow. Without the boundary for initiation, any storms will
be tied to development on the higher terrain to the west with
elevated heating. Upper forcing, if any, is lacking. Also, clouds
will keep temperatures only reaching the upper 70s to lower 80s,
limiting instability. So, only carrying some slight to chance pops
on western and northern fringes of the forecast area for Thursday
afternoon.
.LONG TERM...(Thursday night through Tuesday)
Issued at 1113 AM MDT Wed Jul 25 2018
As of 00Z Friday, the forecast begins with an actively-shifting
pattern due to recent frontal passage. The region is expected to
be situated between an upper-level ridge over the SW CONUS and a
longwave trough over the Great Lakes. Both the NAM and the GFS are
displaying moisture throughout the column from 1000mb - 300mb.
The upper-level ridge is expected to break down and give way to a
longwave trough and its associated frontal system by Monday at
00Z. 300mb.
Friday morning, a warm sector will form between the leeside
trough and the lingering stationary boundary over KS/OK. Friday`s
PoPs indicate precipitation between 00Z and 06Z and again in the
evening and into Saturday morning. Most of Saturday appears to be
wet with precip extending into the early evening. SPC is
anticipating a slight risk for scattered severe storms to form due
to steep mid- level lapse rates, moderately high CAPE values, and
a "strong deep layer beneath 30-40kt northwesterly mid-level
flow." This trend is expected to continue for the remainder of the
weekend. After Sunday, the boundary transitions to a more
organized frontal system and it moves out and goes south, causing
the area to dry out, and no more precipitation is expected through
Wednesday. Higher pressure builds in and conditions become more
stable. Cloud cover is expected to clear out, wind speeds should
return to 10kt or less, and temps steadily rise into the upper
80s-lower 90s by the end of the period.
Friday`s temperatures will be moderated by the recent frontal
passage from Wednesday. High temperatures are expected to be in
the high 70s - low 80s. Low temperatures are expected to be in the
upper 50s- lower 60s. Sunday evening will reach the upper 70s
across the entire area. We are not expected to heat up again
until Tuesday afternoon/evening with temps topping out in the
upper 80s.
&&
.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
Issued at 515 PM MDT Wed Jul 25 2018
GLD will start out VFR with scattered thunderstorms between 04Z-
10Z followed by intermittent IFR conditions due to lower ceilings
first thing Thursday morning between 10Z-13Z. VFR will prevail
after 13Z with light northeast winds turning southeast.
MCK will have VFR conditions with scattered thunderstorms between
03Z-09Z. MVFR conditions due to lower ceilings are expected
intermittently between 11Z-14Z to be followed by VFR conditions
and light northeast winds turning easterly.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...Flash Flood Watch until 3 AM MDT /4 AM CDT/ Thursday for
KSZ001>004-013>016-027>029-041-042.
CO...Flash Flood Watch until 3 AM MDT Thursday for COZ090>092.
NE...NONE.
&&
$$
SHORT TERM...024
LONG TERM...SANDERSON
AVIATION...JSL
Area Forecast Discussion
National Weather Service Gray ME
944 PM EDT Wed Jul 25 2018
.SYNOPSIS...
A weak cold front will push in from the west tonight and will
dissipate over the region on Thursday. A secondary cold front
will approach from the west Thursday night and will stall over
the region by late in the day Friday. The front will gradually
shift offshore on Saturday. High pressure will build in from the
west Saturday night and Sunday. High pressure will shift
offshore on Monday.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
Update...
Continue to monitor mesoscale models and latest radar imagery
for the potential of locally heavy rainfall tonight. As has been
the case for the last few days, most of the showers remain over
New Hampshire and along the NH/ME border in Oxford county.
Expect that trend to continue for another couple hours
Thereafter, a more organized area of showers with embedded
thunderstorms will approach from the waters south of Nantucket
very late this evening or shortly after midnight. Latest HRRR
suggests this heavy precipitation will cross the region mainly
between 06Z and 12Z.
Prev Disc...
Weak cold front will continue to slowly push in
from the west this evening and overnight. Showers ahead of this
boundary are becoming more widespread across New Hampshire and
will be edging into western Maine through early evening along
with scattered thunderstorms. Expect rain to be heavy at times
overnight with most areas picking up 1 to locally 2 inches.
Dense fog lurking along the coast will push inland during the
evening hours. Will see a warm and muggy night with lows in the
mid 60s to lower 70s.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH THURSDAY NIGHT/...
Steady rain will give way to partly sunny skies and scattered
afternoon showers and thunderstorms as weak frontal boundary
generally washes out over the region. Highs will top out in the
mid 70s to mid 80s.
Showers will die out with loss of heating Thursday evening and
expect partial clearing with areas of fog overnight. Lows will
range through the 70s.
&&
.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
Friday morning begins with continued southwest flow aloft in
place over northern New England. As has been the case as of
late, expect scattered showers and isolated thunderstorms to
develop as the day progresses. Chances are higher over the
mountains where orographic lifting will help with initiation.
Not really much in the way of any kind of airmass change, so
fairly warm and humid conditions continue. Saturday looks to be
something of a repeat of Friday, only with slightly more
scattered showers. A weak frontal boundary will finally serve to
scour out some of the humidity as drier air moves in Saturday
night and into Sunday. Relatively quiet conditions continue on
Monday and then Monday night and into Tuesday the trough over
the Great Lakes will amplify a bit. This will once again allow
warmer and more humid air to stream in from the south with an
increased chance of precipitation.
&&
.AVIATION /02Z THURSDAY THROUGH MONDAY/...
Short Term...Areas of IFR/LIFR ceilings and vsby
overnight...mainly in southern interior and coastal zones.
Becoming VFR on Thursday with areas of MVFR/IFR ceilings and
vsby in showers and thunderstorms. VFR Thursday night with areas
of IFR/LIFR ceilings/vsby valley fog.
Long Term...Mainly VFR conditions with IFR/LIFR conditions in
showers and fog Friday night and into Saturday.
&&
.MARINE...
Short Term...
Continuing SCA`s for the overnight through tomorrow morning.
Long Term...No flags expected.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...None.
NH...None.
MARINE...Small Craft Advisory until noon EDT Thursday for ANZ150-152-
154.
&&
JC/WW
Area Forecast Discussion...UPDATED
National Weather Service Jackson MS
934 PM CDT Wed Jul 25 2018
.UPDATE...
Updated for evening discussion.
&&
.DISCUSSION...
The overnight forecast was updated to lower min temps. We remain
in a light northerly flow pattern, providing seasonably dry and
pleasant conditions. Just a few high clouds were sliding across
the Mid South, clipping the Golden Triangle, with a mostly clear
sky to remain overnight. Given the clear and dry conditions, I
see no reason we shouldn`t achieve temps at least as low as this
morning, if not a degree or two lower in a few areas. Forecast min
temps were adjusted downward to reflect more of a persistence
approach. No other notable adjustments were needed. /DL/
Relevant portions of prior discussion below:
Through Thursday: No major concerns for the forecast period.
Latest RAP and satellite analysis continued to show the ridge
trough pattern over the CONUS. This was characterized by anomalous
mid to upper ridging centered over the Desert Southwest US and
troughing east of the MS Valley. On the surface a weak surface
boundary was observed pushing south over southern Mississippi and
eastern Louisiana. With surface high pressure in control, mid
afternoon readings were in the upper 80s to lower 90s. In the wake
of the weak frontal boundary, dewpoints were in the mid to upper
60s, which has brought limited temporary relief to the humid
conditions. For the period, dry conditions are expected to
continue. On Thursday afternoon, a weak shortwave will be
approaching from the northwest as the weak boundary pushes back
north as a warm front by Thursday afternoon.
Highs for Thursday will be from the lower to middle 90s. Heat
indices will push to around 100 degree mark in the south and
west./17/
Thursday night through Tuesday: At the beginning of the period,
surface high pressure over the lower MS valley will be in the
process of being replaced by yet another from the north in continued
mid level northwest flow. For the most part, surface dewpoints will
remain in the 60s late week into the first part of the weekend.
These conditions will allow for efficient warming and deep mixing,
but heat indices should not be much of a problem. This will begin to
change somewhat Saturday afternoon and Sunday afternoon over the
south as dewpoints begin to creep back into the lower 70s. With the
expected heat in the lower 90s, heat indices will climb to near 105.
Meanwhile, a long wave trough will begin dropping south through the
upper MS valley Sunday with its attendant cold front close enough by
Monday for widespread showers and thunderstorms to develop mainly
during the heat of the day Monday. Not much eastward progression
looks to occur as the trough continues to dig south Tuesday into
Wednesday. With the front essentially stalling from northeast to
southwest over the area, good coverages of mostly diurnal convection
should continue through the end of the period./26/
&&
.AVIATION...
00Z TAF discussion:
VFR conditions are expected to continue through tomorrow. There
may be a brief period of MVFR vis reduction in the Delta tomorrow
morning thanks to patchy fog but otherwise, this should not pose
much of an issue for aviation interests. /28/
&&
.PRELIMINARY POINT TEMPS/POPS...
Jackson 68 92 71 94 / 0 0 2 8
Meridian 68 93 71 95 / 0 0 3 8
Vicksburg 68 93 71 94 / 0 0 2 9
Hattiesburg 69 93 72 95 / 1 1 4 14
Natchez 68 94 71 94 / 0 1 2 9
Greenville 68 93 71 89 / 0 0 3 23
Greenwood 67 91 70 90 / 0 0 2 20
&&
.JAN WATCHES/WARNINGS/ADVISORIES...
MS...None.
LA...None.
AR...None.
&&
$$
DL/17/26/28
Area Forecast Discussion
National Weather Service Jacksonville FL
1005 PM EDT Wed Jul 25 2018
.UPDATE...
Convection along the Altamaha River should dissipate by midnight.
The HRRR is very insistent upon bands of convection moving out of
the Gulf of Mexico and across the Florida Peninsula generally
south of State Road 16. As there is convection over the Gulf west
of Tampa and with the general flow in alignment with the HRRR
have added 30-40 percent pops across the Florida Peninsula
overnight.
&&
.AVIATION...Overall have kept convection away from the fields
overnight but the mid shift may have to amend for Gainesville and
St Augustine. Overall VFR conditions overnight.
&&
.MARINE...Upper system over the area will gradually weaken during
the remainder of the week, and will be replaced by an upper level
ridge of high pressure over the weekend. The result will
generally be a persistent south to southwest flow at 10 to 15
knots, with 2 to 4 ft seas through the upcoming weekend.
Rip Currents: Moderate risk through Thursday.
&&
.PRELIMINARY POINT TEMPS/POPS...
AMG 90 73 91 73 / 40 20 40 20
SSI 88 77 89 77 / 40 20 30 10
JAX 90 74 91 74 / 50 20 40 10
SGJ 88 75 89 74 / 60 20 50 10
GNV 89 73 89 73 / 60 30 60 20
OCF 88 74 88 73 / 60 40 60 20
&&
.JAX WATCHES/WARNINGS/ADVISORIES...
FL...None.
GA...None.
AM...None.
&&
$$
Sandrik
Area Forecast Discussion
National Weather Service Medford OR
455 PM PDT Wed Jul 25 2018
Updated aviation discussion.
.DISCUSSION...25/12Z NAM/GFS/EC in.
Lots of marine stratus over the coastal waters this afternoon,
along with a lot of smoke over much of the inland portions of the
CWA. Cumulus is popping up over the ridges from the Cascades east,
and Siskiyous south, but development is less than it was at this
time yesterday.
The southwestern high continues to retrograde. It will be centered
near Las Vegas later today, and it will remain in place there
through Monday.
This is significant in that the four corners position is the
favored location for monsoonal moisture to be advected from the
south into the Medford CWA, thus allowing thunderstorms to
develop. A location farther west, such as the one the high will
move to later today, will cut off the monsoonal moisture, forcing
it to the south and east of the Medford CWA.
Before that happens, there will be one more round of isolated
thunderstorms this afternoon and evening, and the main axis of
activity will from central Siskiyou county east into Modoc county,
and barely into southern Klamath and Lake counties.
No thunderstorms are expected from Wednesday night through early
next week. It`s still going to be very hot inland though. Highs
will be near 15 degrees above normal over the west side and 5-10
degrees above normal east of the Cascades. The west side may cool
a few degrees after Thursday, but highs will remain 10-15 degrees
above normal with the exception of the Umpqua Basin, where
increasing marine influence will bring a bit more cooling.
Temperatures east of the Cascades will continue to be 5-10 degrees
above normal. These hot conditions will continue into next week,
with some cooling possible next Tuesday into Wednesday. Meanwhile,
the marine layer will keep coastal temperatures near normal.
Smoke continues to be concentrated to the southeast of the
ring of fires in northwest Josephine and northern Jackson
Counties. Northwest winds will continue to drive smoke into
Jackson, Josephine, and Klamath Counties primarily, where air
quality readings are consistently in the Unhealthy and Hazardous
ranges. The hourly HRRR smoke forecast model is showing the
persistent pattern of somewhat improving conditions early
afternoon when atmospheric mixing begins, followed by a push of
heavy smoke into valleys in the late afternoon hours as the daily
northwest winds develop. The main determining factor for when
smoke diminishes significantly in area valleys is fire activity.
Until fire activity diminishes, smoke will likely continue to be
unhealthy to hazardous at times.
A weak trough will approach the Pacific Northwest coast next
Tuesday, and the high near Las Vegas will start to progress
eastward again. This may eventually allow monsoonal moisture and
thus thunderstorm activity back into the Medford CWA, but at this
time it looks like that won`t happen through at least next
Thursday.
&&
.AVIATION...For the 26/00Z TAFs...Wildfire smoke continues over most
of the inland areas west of the Southern Oregon Cascades as well as
some locations just east of the Cascades. MVFR visibilities/cigs and
local IFR conditions will prevail over Jackson and Josephine
counties with occasional improvement to VFR. Outside of the smoke,
VFR conditions will prevail for inland areas. Smoke models keep
thick smoke in the Rogue Valley until around 06Z with thick smoke
spreading into the Klamath Basin after 03Z.
Along the coast, marine clouds are just off the coast. This should
return this evening. The TAF shows lowering conditions at 3z, but it
could be delayed by an hour or two. Once the lower conditions
return, it will continue overnight into Thursday morning. Meanwhile
south of Port Orford, marine stratus will likely return again this
evening. -FB
&&
.MARINE...Updated 200 PM PDT Wednesday 25 July 2018...Offshore high
pressure and a thermal trough inland will persist through this week.
There`s good agreement the strongest winds will be around 3nm from
shore west of Cape Blanco southeast to around 20 nm west of Pistol
River. Even then, were only expecting them to remain small craft.
These conditions will persist into Thursday. On Friday, small craft
winds and seas may linger, especially from Cape Blanco southward.
Then winds and seas will diminish Friday night, with relatively calm
conditions Saturday through early next week. -Petrucelli
&&
.FIRE WEATHER...Updated 200 PM PDT Wednesday 25 July 2018...
There remains a slight chance for an isolated storm or two in
northern California this afternoon and evening. We`re expecting
storms to form around eastern Siskiyou County and head eastward
towards Modoc County. The lightning activity will be significantly
less compared to the last two days.
For Thursday, breezy winds and dry RH`s will contribute to an
elevated fire weather risk during Thursday afternoon and early
evening. Model guidance is suggesting a Red Flag warning for parts
of the Rogue Valley and the northern sections of the Illinois valley
near Grants Pass. Given the wind guidance and our local statistical
guidance for RAWS sites, we went with a red flag warning for a large
portion of FWZ 622 and FWZ 620. See the Red Flag warning or our
detailed hazards page for more details on locations.
Friday is looking similar to Thursday as the pressure gradient
between Roseburg and Montague is about 5.5 mb, which is very close
to what will occur Thursday. However, with relatively cooler
temperatures and thus lower mixing, RH`s should trend upwards. So
there is some concern about fire activity on Friday, but it should
be trending downward compared to Thursday.
After looking through the extended forecast, this hot and dry
pattern will likely continue up to Monday when a trough moves in off
the coast of Oregon. This has been identified as a critical fire
weather pattern because the trough is helping replace a stagnant dry
airmass.
-Smith
&&
.MFR WATCHES/WARNINGS/ADVISORIES...
OR...Heat Advisory until 11 PM PDT Thursday for ORZ024-026.
Red Flag Warning from 2 PM PDT through 7 PM PDT Thursday
for ORZ620-622.
CA...Heat Advisory until 11 PM PDT Thursday for CAZ080>082.
Pacific Coastal Waters...Small Craft Advisory until 11 PM PDT
Thursday for PZZ356-376.
Small Craft Advisory for hazardous seas until 11 PM PDT Thursday
for PZZ356-370-376.
$$
15/15/10
Area Forecast Discussion
National Weather Service Newport/Morehead City NC
936 PM EDT Wed Jul 25 2018
.SYNOPSIS...
A stationary boundary will linger over the middle of the state
into this weekend, lifting to the north early next week. High
pressure will remain anchored over the offshore waters into
next week.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
As of 935 PM Wednesday...Another band of showers and
thunderstorms producing a few heavy downpours and frequent
lightning is moving across the southern zones at late evening.
Some additional thunderstorms were observed in the Wilmington
area. Latest HRRR and NSSL WRF models continue to show some
redevelopment of showers/storms along the coast late tonight
into early Thursday morning. Given deep instability and
moisture, will keep a 30-40 percent PoPs going overnight. Muggy
southwest flow will keep low temperatures in the low to mid 70s
for most areas tonight. A few patches of fog or stratus may
occur if some clearing occurs given light winds and a wet
ground.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH 6 PM THURSDAY/...
As of 315 pm Wed...Summertime pattern returns. Scattered
convection possible off the coast in the morning, then
transition to scattered inland convection in the afternoon.
Highs will be in the upper 80s inland to mid 80s Outer Banks and
south coast.
&&
.LONG TERM /THURSDAY NIGHT THROUGH WEDNESDAY/...
As of 245 AM Wed...Models remain in good agreement with the
typical summertime pattern. More active weather may move back
in for the weekend into early next week.
Thursday night through Friday...Only isolated to scattered
convection mainly during the afternoon hours Fri. Highs more
typical for the peak of the summer in the upper 80s to around 90
interior to mid/upr 80s coast. Lows in the lower to mid 70s.
Saturday through Tuesday...25/00Z med range model suite in
fairly good agreement with broad upr trough amplifying across
the Great Lakes region and digging into the lower MS River
Valley this weekend, with sfc front sagging south into the Mid
Atlantic to Southeast states. It appears front will remain north
and west of E NC, though hts fall enough to warrant somewhat
better chances of showers/storms for the weekend into early next
week as afternoon/evening convective coverage will be a bit
more widespread, esp for interior zones. Afternoon highs
knocked back a few degrees generally into the mid/upr 80s most
areas. Overnight lows still seasonably warm in the 70s.
&&
.AVIATION /02Z THURSDAY THROUGH MONDAY/...
Short Term /through 00Z Friday/...
As of 640 PM Wednesday...Some MVFR ceilings being observed in
convection at KOAJ, which may impact the other TAF sites over
the next 2 or 3 hours. Would anticipate this activity to wane
with loss of heating. While expect mostly VFR conditions through
this TAF cycle, will continue previous trend of showing a period
of MVFR ceilings early in the morning at the TAF sites as skies
clear somewhat with a rather wet ground from recent days of
rainfall. VFR conditions should prevail during the day Thursday
with mostly a mid-cloud deck expected.
Long Term /Thu Night through Sunday/...
As of 245 AM Wed...A return to mainly VFR Thursday Night through
Friday as typical summertime pattern returns with just
scattered to isolated showers/storms each afternoon. Perhaps
better chance of lowered vsbys/cigs this weekend as better
chances for showers/storms moves in.
&&
.MARINE...
Short Term /through Thu/
As of 935 PM Wednesday...No major changes to the current
forecast. S/SW winds will continue at 15-25 knots over the
coastal waters tonight, and may be enhanced at times by
convection. Winds on the Pamlico Sound will run 15-20 knots.
Elsewhere, mostly 10-15 knot winds are expected. Seas are
running 4-6 feet current and that should continue overnight.
Winds and seas subside from north to south early Thursday into
Thursday afternoon as high pressure offshore becomes
predominant.
Long Term /Thursday night through Sunday/...
As of 245 AM Wed...Winds and seas diminish Thu night into next
weekend with shift to more typical mid-summer Bermuda high
pattern with SW winds 5-15 kt. Seas will generally be 3-5 ft
through Sat then 2-4 ft by Sunday.
&&
.MHX WATCHES/WARNINGS/ADVISORIES...
NC...Beach Hazards Statement through Thursday evening for NCZ095-
098-103-104.
MARINE...Small Craft Advisory until 2 PM EDT Thursday for AMZ154-156-
158.
Small Craft Advisory until 6 AM EDT Thursday for AMZ150.
Small Craft Advisory until 11 AM EDT Thursday for AMZ152.
&&
$$
SYNOPSIS...HSA
NEAR TERM...CTC
SHORT TERM...HSA
LONG TERM...TL
AVIATION...CTC/TL/MS
MARINE...CTC/HSA/TL
Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
1102 PM CDT Wed Jul 25 2018
.Updated for 06Z Aviation Discussion...
Issued at 1055 PM CDT Wed Jul 25 2018
&&
.SHORT TERM...(This evening through Thursday)
Issued at 237 PM CDT Wed Jul 25 2018
As of early this afternoon, a cold front stretched southwest to
northeast across western MN, already having moved through Alexandria
and quickly approaching the St. Cloud area as it moves southeast.
Some clearing today has helped steepen low level lapse rates and
latest RAP analysis and forecast indicates 1,000-2,000 j/Kg of CAPE
along and south of the front through the afternoon. A few very
spotty cells are beginning to break out across southern and central
MN in the warm sector where temperatures are in the mid to upper 70s
with dew points in the mid 60s.
Expecting additional thunderstorm development through the afternoon,
but an analysis of model soundings indicate a long skinny-CAPE setup
with mainly speed shear, but a lack of directional shear. The slight
risk area clipping far eastern MN and western WI still looks to be
our best bet to get strong storms as the afternoon wears on with
more time to destabilize in the warm sector. The skinny CAPE and
unidirectional deep shear environment will produce scattered
thunderstorms along the front through the afternoon, but most storms
should be sub-severe. A few strong storms would pose a risk of
damaging winds, and possibly large hail.
The front will clear the area from west to east, with clearing skies
likely tonight behind the front. Cold air advection will ensue for
Thursday, with a stratocu deck expected to drop in from the north as
we remain in deep cyclonically curved flow on the west side of the
deep upper trough. Highs tomorrow will be held in the upper 60s to
low 70s with northwest winds of 10-20 MPH.
.LONG TERM...(Thursday night through Wednesday)
Issued at 237 PM CDT Wed Jul 25 2018
Quiet & pleasant to start of the long term period with a broad area
of high pressure across the northern plains & northwest flow aloft
keeping our temperatures a few degrees below normal & skies, for the
most part, sunny. Can`t rule out some precip chances Saturday &
Sunday as the jet aloft pivots over the area & cooling temperatures
aloft allows for some diurnally-driven scattered showers &
thunderstorms. Chances look a little better on Sunday afternoon
compared to Saturday as a bit more of an organized vorticity maxima
passes over the area. Regardless, expect most areas to stay dry for
most of the the weekend given the scattered coverage so expect a
cooler & partly sunny weekend, but be prepared for a passing shower
or two.
Beyond the weekend, we remain under the deep upper-level trough over
the Great lakes with 500 mb heights on the order of 2 standard
deviations below the mean for late July/early August. A few
perturbations aloft will continue to pass overhead & potentially kick
off a few scattered showers & thunderstorms each afternoon but
otherwise things are expected to stay dry. Temperatures slowly
rebound back into the mid-80s by Wednesday as the ridge over the
southwest begins to build back into the upper Midwest.
&&
.AVIATION...(For the 06Z TAFS through 06Z Thursday night)
Issued at 1055 PM CDT Wed Jul 25 2018
VFR conditions overnight, but should see clouds move in from the
north. Should see MVFR clouds by morning, and these will gradually
lift throughout the day, but cold air advection will keep cloud
bases from rising too quickly. By mid to late afternoon most sites
should be above 3000 ft with overcast skies. Northwest winds will
gust near 20kts on Thursday, but taper off again after sunset.
KMSP...
VFR conditions should give way to MVFR by morning, but cloud bases
are expected to remain above 1700 ft. Should see VFR conditions by
the afternoon as cloud bases lift throughout the day.
/OUTLOOK FOR KMSP/
FRI...VFR. Wind NW at 05 kt.
SAT...VFR with small chance of -shra. Wind VRB at 05 kt.
SUN...VFR with small chance of afternoon -shra. Wind NW at 05 kts.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
&&
$$
SHORT TERM...SPD
LONG TERM...ETA
AVIATION...jrb
Area Forecast Discussion
National Weather Service Phoenix AZ
230 PM MST Wed Jul 25 2018
&&
.SYNOPSIS...
Excessively hot weather will continue for a few more days with near
record highs for many locations. Moisture will slowly move back into
the region allowing temperatures to eventually retreat back to near
normal levels by the weekend. In addition, more expansive
thunderstorms will begin over higher terrain areas of Arizona, then
gradually spread towards lower elevation communities during the
weekend and early next week.
&&
.DISCUSSION...
Another day of excessive heat across the region, with very strong
ridging aloft (500 mb heights upwards of 600dm). So far, the high at
Sky Harbor has been 115F, with another degree or two possible rise
before the final high is reached. Current 88-D radar and satellite
imagery is showing convective development over the higher terrain to
our north. The last several runs of the HRRR High-res model showing,
under light northwesterly flow aloft, the current convection over
Yavapai County attempting to make a run towards the lower deserts.
However, a rather hostile environment over the lower deserts (rather
low MUCAPES (just a couple of hundred J/KG), high CIN, and a mid-
level cap will likely kill the storms before they reach the lower
deserts. However, there is a slight chance that they could affect
parts of extreme northern Maricopa County and La Paz County before
they dissipate. More likely, outflows from these storms will push
into the lower elevations, producing gusty winds and a few areas of
blowing dust this evening. Southern Gila County will likely also see
isolated storms, especially over the higher elevations. Gusty winds
and brief heavy rains will be the primary threat, given the high
DCAPE values (in the 1000-2000 J/KG range).
.PREVIOUS DISCUSSION...
Thereafter tonight, it still appears very likely a deeper, more
pronounced Gulf surge will spread through SW and south-central
Arizona with low/mid 60 dewpoints pushing all the way into foothill
locations north and east of Phoenix Thursday morning. If the
forecast Sonoran convective complex is strong enough, it is possible
gravity wave/outflow influences could once again spark elevated
morning storms somewhere through central Arizona Thursday though
these mesoscale details are impossible to pinpoint at this time.
More importantly, the increased moisture (along with some presumed
more prevalent mid/high clouds) will diminish the most extreme heat,
however winds trajectories indicate the plume of moisture influence
only from SW Arizona through the Phoenix vicinity. Thus, excessive
heat will continue through much of SE California and west central
Arizona Thursday where high temperatures in excess of 115F will
continue for communities such as El Centro, Blythe, and Parker.
More pronounced outflows and an increasingly higher theta-e airmass
from convective complexes over Sonora and SE Arizona should
progressively feed into central and western Arizona beginning
Thursday night, but really becoming more apparent Friday night.
There is already some model guidance suggesting more organized,
stronger outflows blasting into the eastern and southeast part of
the CWA Friday evening (i.e. classic blowing dust generation area)
though an initial lack of better quality moisture may preclude much
actual thunderstorm activity at lower elevations. Other than the
potential for dense dust, this outcome will be welcome in further
reducing excessive temperature levels, though it is conceivable
areas of SE California further removed from the outflow could
experience yet another day of excessive heat Friday.
This evolution will set the stage for a more convectively active
period through the weekend, and 00Z GFS output along with some local
high resolution data indicate much more expansive, stronger storms
Saturday afternoon/evening. Conceptually given the pre-exiting steep
lapse rates and higher DCape values, strong storms would be
preferred into lower elevations initially with a greater wind and
dust threat. Each successive day would add more moisture to the
environmental profile yielding a higher flood threat (and especially
given the weaker steering flow near the high pressure center), yet
still maintaining these other thunderstorm hazards. Undoubtedly,
there will be at least one very active day/evening (potentially
Saturday) followed by some less active days through the weekend and
early next week time frame.
&&
.AVIATION...
South-Central Arizona including KPHX, KIWA, and KSDL:
Confidence is increasing that a strong outflow boundary will
approach from the north later this afternoon, given the high
coverage of storms expected across the higher terrain north of
Phoenix. Timing of this boundary as always is uncertain, but the
current best estimate is between 00-01Z across the Phoenix area.
Gusty winds nearly out of the due north can be expected if this
boundary materializes, with occasional gusts to 20-25 mph
anticipated. Currently not expecting any thunderstorm activity
near area terminals due to the very dry low-level air in place,
but will continue to monitor short-term trends and update as
necessary.
Otherwise, west winds should predominate at KPHX throughout the
TAF period, with low confidence in a switch out of the east.
Higher confidence this will occur at KIWA overnight. Could see
cigs lower to around 15 thousand feet overnight at all area
terminals in association with thunderstorm activity over the
higher terrain, before gradually improving by mid-late Thursday
morning.
Southeast California/Southwest Arizona including KIPL and KBLH:
There are no major aviation weather concerns through Thursday
morning. The winds will maintain a more southerly component at
KBLH while more southeasterly for KIPL.
Aviation Discussion not updated for amended TAFs.
&&
FIRE WEATHER...
Saturday through Wednesday:
Storm chances will increase over the weekend and through the first
part of next week with activity gradually spreading into lower
elevation districts. Temperatures will finally cool to a near
seasonal average over the weekend. Correspondingly, minimum humidity
levels will increase towards a 20-35% range while overnight recovery
becomes good. Somewhat elevated and gusty south to southwest winds
on Saturday will relax thereafter becoming more typical of the
monsoon season next week.
&&
.CLIMATE...
Record high temperatures:
Date Phoenix Yuma
---- ------- ----
July 25 115 in 1943 120 in 1943
&&
.SPOTTER INFORMATION STATEMENT...
Spotters should follow standard reporting procedures.
&&
.PSR WATCHES/WARNINGS/ADVISORIES...
AZ...Excessive Heat Warning until 8 PM MST this evening for AZZ531-
532-534>556-559>562.
Heat Advisory until 8 PM MST this evening for AZZ557-558-563.
Excessive Heat Warning until 8 PM MST Thursday for AZZ530-533.
CA...Excessive Heat Warning until 8 PM PDT this evening for CAZ564-
565.
Excessive Heat Warning until 8 PM PDT Thursday for CAZ560>563-
566>570.
&&
$$
DISCUSSION...Percha/MO
AVIATION...Rogers/Kuhlman
FIRE WEATHER...Percha/MO
CLIMATE...MO
Area Forecast Discussion
National Weather Service Pueblo CO
723 PM MDT Wed Jul 25 2018
.UPDATE...
Issued at 716 PM MDT Wed Jul 25 2018
Quick update was done to pull down severe watch #307 for Teller
and El Paso counties. Latest high res model runs suggest another
round may move into the Pikes Peak region between 03-06z...though
best instability and threat area may end up being farther to the
east. Will continue to monitor this potential through the
evening, but for now have let the watch expire. -KT
&&
.SHORT TERM...(This evening through Thursday)
Issued at 342 PM MDT Wed Jul 25 2018
Currently...Cold front moved into the area somewhat quicker than
the models suggested, likely due to the convection earlier this
morning over Nebraska. Showers and thunderstorms are developing
over the eastern mountains.
.Tonight and Thursday...Trough will pass to our north and east
this evening. High resolution models continue to show stronger
convection developing over El Paso and Teller Counties later this
afternoon into the evening. There is enough shear and instability
to get a few strong to severe storms in El Paso Counties early
this evening. As disturbance moves southeastward, anticipate
storms will develop in the evening over Kiowa County and move to
the southeast. Still currently looks like best chances for
stronger storms will be north and east of a line from Colorado
Springs to Lamar. Latest HRRR suggest some of the storms could
move into Baca County later tonight with additional rainfall.
.Thursday...Another day with plenty of low level moisture on the
plains and eastern mountains. The GFS and NAM are focusing on the
strongest storms to be along the eastern mountains and near the
Interstate 25 corridor. SPC has marginal risk for these region
which is reasonable given the shear and marginal CAPE. Main
threats will be locally heavy rains, and will have to watch the
recent burn scars. Further west, still enough monsoon moist for
diurnal convection but main monsoon plume will be south of the
region.
.LONG TERM...(Thursday night through Wednesday)
Issued at 342 PM MDT Wed Jul 25 2018
.Friday through Sunday...Continued generally wet pattern for the
eastern mountains and eastward with low level moisture remaining
on the plains. Cold frontal passage on Saturday will bring in
another surge of low level moisture. On Sunday, a sharper trough
will move over the region with another cold front bringing in more
low level moisture. There could be increased chances for severe
weather on Sunday with increased shear, forcing and low level
moisture. Still to early to be very specific as many finer
details have yet to be resolved. Further west, still some monsoon
moisture wrapping around the upper high for some scattered diurnal
convection.
.Monday through Wednesday...Upper ridge retrogrades with drier
northerly flow aloft developing. In addition, better low level
moisture will move east and south of the region. Grids have a
general drying trend with some residual monsoon moisture producing
some diurnal convection. --PGW--
&&
.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
Issued at 342 PM MDT Wed Jul 25 2018
Some thunderstorms will continue through mid evening at the TAF
sites with the best chances for storms at KCOS. The storms near
KCOS could be strong. On Thursday, the pattern continues with
better low level moisture at KCOS and KPUB. Models suggest more
TSRA at KCOS and KPUB than what occurred on Wednesday, while
coverage at KALS will be similar to Wednesday. _PGW--
&&
.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
Issued at 342 PM MDT Wed Jul 25 2018
Some thunderstorms will continue through mid evening at the TAF
sites with the best chances for storms at KCOS. The storms near
KCOS could be strong. On Thursday, the pattern continues with
better low level moisture at KCOS and KPUB. Models suggest more
TSRA at KCOS and KPUB than what occurred on Wednesday, while
coverage at KALS will be similar to Wednesday. _PGW--
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...KT
SHORT TERM...PGW
LONG TERM...PGW
AVIATION...PGW
Area Forecast Discussion
National Weather Service Raleigh NC
1013 PM EDT Wed Jul 25 2018
.SYNOPSIS...
An upper level trough will drift east across the Appalachians
tonight, then reach the East coast by Thursday afternoon. A surface
trough will otherwise linger over the Carolinas ahead of a cold
front that will settle into, then become quasi-stationary over, the
southern middle Atlantic states this weekend.
&&
.NEAR TERM /TONIGHT/...
As of 1010 PM Wednesday...
WV satellite imagery indicates the mid-upr low that for days had
been situated over the sern US, has deamplified into the nrn middle
Atlantic states, downstream of an upr level, full latitude
("kicker") trough analyzed in 00Z upr air data from near Hudson Bay
swd into the srn Appalachians and nern Gulf of Mexico. That upr
level trough will move ewd into the cntl Carolinas by 12Z Thu.
At the surface, a remnant frontal zone, and persistent
trough/convergence axis and approximate wrn bound of a richer
maritime Tropical airmass characterized by surface dewpoints aoa 70
degrees, was analyzed at 02Z from near CHO swd to GSO and CLT, then
swwd across cntl GA and srn AL. This feature is expected to remain
quasi-stationary overnight.
The combination of subsidence behind the ejecting wave over the nrn
middle Atlantic states, and widespread convective overturning from
the earlier multi-cell convection and composite outflow that has
since moved to the NC coast, has resulted in mainly dry conditions
over cntl NC this evening. However, weak instability and CINH --the
former around 1000 J/kg or less per both the observed 00Z GSO RAOB
and RUC objective analysis data-- suggests a few showers may yet
percolate over cntl NC tonight, particularly in the vicinity of the
aforementioned lingering surface front/trough, as the upr level
trough axis approaches.
Lingering mid-high level cloudiness, mostly remnants from earlier
convection, should continue to thin overnight. That (at least)
partial clearing, in conjunction with abundant low level moisture
from both saturated soil and the aforementioned, remaining maritime
Tropical air, will favor the development of fog and low clouds late
tonight-Thu morning. It will otherwise be a muggy/humid night-
morning, with lows in the upr 60s to lwr 70s.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH THURSDAY NIGHT/...
As of 345 PM Wednesday...
Drier air will finally start to move into the area Thursday as
the upper level trough axis that has been over the region for
the last couple of days collapses. As this happens PWATs across
the western zones will fall to around 1.25" (on the GFS and NAM)
while around 1.7" towards our eastern zones. A surface front
will also stall across the triad during the afternoon while a
sea breeze works inland from the coast. The high res are showing
scattered convection at best across our eastern counties.
Thursday night the front will wash out with southerly flow
returning to all TAF sites. Thursday night the area will remain
precipitation free.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
As of 245 PM Wednesday...
A brief reprieve from at least widespread POPs is expected to
continue on Friday as NC finds itself in the subsidence region of a
departing area of low pressure riding North along the DELMARVA
Peninsula. This break won`t last long, however, as an upper level
trough begins to dig south/east through the Ohio Valley with its
associated cold front arriving on our northwestern doorstep by
Friday evening. This front is likely to stall somewhere over central
NC over the weekend, before moving north as a modified warm front
Sunday night/Monday. Behind the boundary, the sub-tropical high is
expected to strengthen and build west as the trough remains just
west of our area, providing enhanced southerly/southwesterly flow
into the region through at least midweek. This will help build an
airmass characterized by 1.75 to 2.5 inch PWAT values over the
Coastal Plains of the Mid Atlantic ahead of an approaching cold
front likely to push in before stalling across central NC through
the middle of next week. In short, expect the wet weather pattern to
once again return, with at minimum CHC/LKLY POPS for much of next
week.
Thicknesses look to remain near/slightly below normal through the
period. The warmest days will likely occur on Friday/Saturday, with
afternoon highs generally in the upper-80s to low-90s. A bit cooler
next week thanks to abundant moisture/cloud cover/precipitation.
Overnight lows will settle into the low 70s.
&&
.AVIATION /00Z THURSDAY THROUGH MONDAY/...
As of 830 PM Wednesday...
Showers and storms have decreased in coverage and intensity this
evening will the loss of heating. However, scattered showers and
isolated storms will continue to be possible through mid/late
evening, before dry weather is expected by early Thursday morning as
the mid level trough axis begins to shift eastward and slowly into
the region. With light and variable to calm winds expected, coupled
with clearing skies overnight sub-VFR visbys (generally MVFR/IFR)
will be possible in the 8-12Z time frame, with possibly some low
status across far east/southeastern central NC (KFAY stands the best
chance of seeing some IFR/LIFR cigs).
VFR conditions are expected to return by at least mid/late morning
(lingering the latest into the morning at KFAY). Thursday afternoon
much drier air will work into the western taf sites with PWATs
falling to around 1.25". Across the eastern TAF sites dry air will
filter in, but PWATs will only fall to around 1.70". Due to this
think primary area for precipitation will remain across the eastern
TAF sites Thursday, though coverage is expected too low to included
any mention in the TAFS at this time.
Outlook: Generally VFR conditions are excepted, with a chance of
mainly afternoon and evening storms Sat. through Mon., increasing in
coverage each day.
&&
.RAH WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SYNOPSIS...MWS
NEAR TERM...MWS
SHORT TERM...HAINES
LONG TERM...MORROW
AVIATION...BSD/HAINES
Area Forecast Discussion...UPDATED
National Weather Service Tampa Bay Ruskin FL
824 PM EDT Wed Jul 25 2018
.UPDATE...
The upper-level trough over the Florida Peninsula will
lead to a persistent SW Flow overnight and into the day
tomorrow. Based on UA data from the 00Z balloon launch and
current HRRR forecasts overnight, showers and possibly some
thunderstorms remain in the forecast overnight. Accordingly
have adjusted POPs grids a bit to reflect higher rain
chances mainly from Tampa Bay northward for the overnight
hours across the region. Have allowed the rip current
advisory to expire as winds tomorrow will be a bit lighter
tomorrow reducing the risk somewhat across area beaches.
Temperatures once again will be warm with overnight lows
in the middle to upper 70s...near 80 along the immediate
coast.
&&
.AVIATION...
VFR expected through much of the period with persistent SW
wind regime. Winds overnight may become a bit more southerly
near the coast at times however. Overnight, showers will
push onshore mainly from Tampa Bay north so will keep VCSH
in the forecast overnight. During the afternoon hours
Thursday SW winds around 10 knots expected although winds
could become gusty at times, perhaps approaching 20 knots,
especially at PIE and SRQ.
&&
.MARINE...
A ridge of high pressure tracking from south to north of the
waters through the period with prevailing winds shifting from
southwest and west to southeast to east. Although onshore winds
are expected to set up in afternoon seas breezes during the
weekend and early next week...when the ridge axis is north of the
waters. Wind speeds generally benign however they...along with
seas...will be higher in and near thunderstorms.
&&
.Preliminary Point Temps/PoPs...
TPA 78 89 78 90 / 40 50 30 30
FMY 77 92 78 91 / 30 30 10 60
GIF 76 91 76 92 / 20 60 10 50
SRQ 79 89 79 89 / 30 50 20 30
BKV 75 89 74 90 / 40 50 20 30
SPG 79 88 79 90 / 40 50 30 30
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...Beach Hazards Statement through Thursday evening for
Coastal Charlotte-Coastal Lee-Coastal Sarasota.
Gulf waters...None.
&&
$$
UPDATE...Flannery
AVIATION/MARINE...11/McKaughan
UPPER AIR...27/Shiveley
DECISION SUPPORT...24/Hubbard