Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 08/14/18
Area Forecast Discussion...UPDATED
National Weather Service Albuquerque NM
541 PM MDT Mon Aug 13 2018
.AVIATION...
00Z TAF CYCLE
Storms generally moving from north to south late this afternoon/early
evening before gradually dissipating prior to 14/06Z. Brief MVFR
cigs/vsbys along with small hail and wind gusts to around 40kt
possible with the stronger storms. Convection is forecast to diminish
aft 14/06Z. Main change Tuesday will be west winds aloft across the
northeast third of the state pushing storms to the east around 15kts.
33
&&
.PREV DISCUSSION...310 PM MDT Mon Aug 13 2018...
.SYNOPSIS...
High pressure aloft centered just west of New Mexico will gradually
shift eastward through mid-week becoming centered squarely over
central sections of the state by Wednesday. At the same time, a weak
boundary is expected to sag into northeast New Mexico later Tuesday.
This will create a favorable environment for a few strong to briefly
severe storms the next few days. Otherwise, thunderstorms that form
over and near the higher terrain will slowly move toward the south or
southeast through Tuesday before steering winds become even weaker
for Wednesday and Thursday. Daytime temperatures will remain a little
above normal, especially Wednesday. The upper high should weaken for
the latter half of the week allowing for increased shower and
thunderstorm coverage especially on Friday and Friday night. Drier
air could limit storm coverage by Sunday with the best chances
across southern and eastern New Mexico.
&&
.DISCUSSION...
Closed low vicinity of the western OK panhandle slowly pivoting
eastward but still slower with a deeper/better defined circulation
than what the latest models have depicted. Farther west, main upper
high center just west of the Four Corners. Resultant north to south
steering flow continues over much of the area. Convective parameters
across the eastern high plains /MU CAPE 2000-2500 J/kg/ much more
favorable going into the rest of the afternoon/evening, especially
the northeast where surface dew points have recovered from yesterday`s
drying episode. The latest HRRR suggests a few strong to briefly
severe storms possible, especially along/just west of the Pecos
River Valley from Santa Rosa to Ft Sumner to north of Roswell.
Elsewhere, will monitor convection rolling toward the south off the
higher terrain with areas along the immediate east slopes, the upper
RGV and northwest third, and upper Gila most favored.
Models similar showing building 500mb heights over the area Tuesday-
Tuesday night as the upper high shifts eastward. This should limit
overall coverage a tad except across the northeast where a
southward-sagging boundary is expected to bolster storm coverage
there beneath a weak northwest flow aloft. Lighter steering winds
would keep central/western valleys pretty quiet until late day or
evening with outflow boundary interactions key. Mid- to upper- level
ridge axis then takes on a NW to SE orientation over New Mexico
Wednesday and Wednesday night. This will favor the northeast and
southwest quarters of the area for the most vigorous/persistent
convection and would not be surprised if a few strong/severe storms
cross the the northeast highlands/far northeast plains. We`ll be
watching the progress of an inverted trough that may impact far
southwest areas of the state and the NAM is quite bullish on QPF vice
the GFS/ECMWF.
Main focus in the extended periods is the approach of a shortwave
trough that translates eastward over the Great Basin Friday and
toward the central Rockies Friday night. This will effectively weaken
the upper high over our area and force any defined center east/south
with enough weakness in the ridge to allow a decent sub-tropical
plume to focus northward with some interplay with some weak large-
scale forcing for ascent especially northern areas. Drying then
indicated the follow with the best storm chances shifting to the east
and south by Sunday. KJ
&&
.FIRE WEATHER...
No critical fire weather conditions anticipated through the upcoming
weekend. Overnight humidity recoveries will generally be good to
excellent, but there will be only fair recoveries far northwest New
Mexico. Locally fair to poor ventilation central and east Tuesday,
with some improvement Wednesday, then areas of poor rates forecast
for the west and north Thursday and Friday.
With high pressure aloft moving over Arizona and New Mexico, storm
motion through tonight will be generally from north to south, except
in the northeast where it will be more from northwest to southeast.
Showers and storms which fire over the higher terrain will drift
down into the lower elevations this evening and into the northeast
and east central plains. The storms in the plains will be aided by a
frontal/outflow boundary tonight but short term models indicate this
activity will diminish after midnight.
Tuesday through Wednesday, low level easterly flow will support
moisture in the east, while the Rio Grande Valley will experience a
burst of east winds during the evenings which helps slosh moisture
westward. Therefore, showers and thunderstorms will likely be more
widespread Tuesday and Wednesday afternoons and evenings. Storm
motion may become slower and more erratic, increasing the potential
for heavy rainfall. Highs will be within a few degrees of normal.
The upper high center may wobble to the southeast of New Mexico late
this week, then re-form and/or strengthen back to our west early
next week. A stronger front is forecast to push into eastern New
Mexico Sunday night/Monday. Thursday through Saturday look fairly
active with scattered to numerous showers and thunderstorms,
although drier air may inhibit convection over the far northwest
corner.
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
41
Area Forecast Discussion
National Weather Service La Crosse WI
616 PM CDT Mon Aug 13 2018
.SHORT TERM...(This evening through Tuesday)
Issued at 208 PM CDT Mon Aug 13 2018
Mostly sunny/clear skies to continue through tonight. Introduced
patchy valley fog after 14.06Z given clear skies, light winds,
and low surface dewpoint depressions. Still some uncertainty with
the depth of the light wind layer, but enough similarities to this
morning`s set-up to add it to the forecast. Lows tonight will
range from the mid 50s to mid 60s.
13.19Z water vapor loop shows two well-defined cut-off lows. The
first is across the lower Great Lakes/Ohio River Valley while the
second is centered over the CO/NM/OK/TX border region. It is this
second low that will drift slowly eastward through Tuesday,
although most of its energy will remain south of the forecast
area. At the same time, a Canadian trough will pass to the north.
Latest guidance suggests little interaction between these two
features, thus limiting the deep layer lift necessary for
convective development. Will maintain 20 to 30 POPs Tuesday
afternoon across much of the area as a weakening cold front moves
through, but wouldn`t be surprised if some areas remain dry. For
those areas that see rain, amounts will generally be a quarter of
an inch or less. Tomorrow will otherwise be another warm day with
highs in the mid 80s to near 90 degrees.
.LONG TERM...(Tuesday night through Monday)
Issued at 208 PM CDT Mon Aug 13 2018
On Tuesday night, the 13.12z models continue to show that the
moisture transport and instability will weaken along the cold front
north of the Interstate 90 corridor. Meanwhile, further to the
south, scattered showers and storms will continue as a weakening
short wave moves northeast through the Upper Mississippi River
Valley. With the best moisture remaining to our southeast, not
anticipating that much rain from this system. Rainfall totals will
be up to a quarter of an inch.
From Wednesday into Wednesday night, the closed upper level low will
slowly transition from eastern Iowa into the Lower Great Lakes. As
this occurs, scattered showers and storms will be seen across the
region. The highest rain chances will be on Wednesday where some
locations may see up to a quarter of an inch. With the Canadian
model appearing to be a wet outlier, lowered the QPF for Wednesday
night.
With less cold air advection into the region, raised the maximum
temperatures by a couple of degrees for the high temperatures on
Wednesday.
From Thursday afternoon through Friday, the models continue to show
that a short wave trough will move southeast from the Northern
Plains into the Mid Mississippi River Valley. There has been a
slight southern shift in the track of this wave. If this trend
continues, we may be able to dry out areas north of Interstate 90.
For the weekend, the models continue to show some ridging building
across the region. 925 mb temperatures respond to this by warming
us into the lower 20s. As a result, we should see a return to above-
normal temperatures.
For early next week, there are still timing issues of a short wave
trough moving out of Canada. Since there are no clear indications
on which model is correct on its timing, made no changes to the
model consolidation.
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 616 PM CDT Mon Aug 13 2018
An area of high pressure was centered over northern Illinois late
this afternoon and is not expected to move much overnight. With
this position of the high, there looks to be the potential for
valley fog tonight. Forecast soundings from the 13.18Z NAM and
13.21Z RAP both show a relatively deep layer of light winds from
the surface up to four thousand feet or so and with light south
winds on the back side of the high, the winds are favorable for
fog. Skies should be clear with the only problem being whether
saturation will occur at the surface or not. The NAM does show
saturation occurring right at the surface with a very dry layer
above that while the RAP does not show saturation occurring. For
now, will stay with the previous forecast of 3sm at KLSE with some
fog and monitor temp/dew point trends through the evening. A cold
front will approach from the northwest Tuesday afternoon but the
majority of the forcing is expected to stay south of both airports
closer to the upper level low that will be moving from Kansas into
Missouri. Will include some diurnal cumulus with the front but
confidence too low to include any mention of VCSH/VCTS.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
IA...None.
&&
$$
SHORT TERM...Rogers
LONG TERM...Boyne
AVIATION...04
Area Forecast Discussion
National Weather Service Bismarck ND
916 PM CDT Mon Aug 13 2018
.UPDATE...
Issued at 916 PM CDT Mon Aug 13 2018
Scattered showers and isolated thunderstorms continued moving east
across central North Dakota. Expect northwestern and north central
North Dakota to be free of showers after midnight. However, models
are still supporting increase in showers and thunderstorms for south
central and southeastern North Dakota late this evening and
overnight. A weak upper level impulse is forecast to move across
southern North Dakota, moving over an area where mixed layer CAPE
remains along and behind the cold front (now extended from central
Minnesota to near Wahpeton to central South Dakota).
Have adjusted hourly precip chances accordingly. Otherwise
temperature forecast remains on track.
UPDATE Issued at 627 PM CDT Mon Aug 13 2018
Increased coverage of slight/small chances of showers and
thundershowers, as latest high res models not really picking up on
all of the convective activity. The northeast to southwest oriented
showers were oriented behind the cold front, which extended from
north central Minnesota to near Fargo to south of Jamestown into a
surface low in central South Dakota. The other area of scattered
showers and thunderstorms over Williams/McKenzie/Mountrail counties
was moving east/northeast, along weak upper level impulses - with
initial enhanced lift from the secondary cold front (much cooler air
in northern ND with temperatures currently only in the 60s).
Global and high res models still indicating some increase in
convective activity later this evening and overnight along northern
WY/SD and into southeastern ND (and in the James Valley in south
central/southeastern ND). Thus increased chances there as well.
Otherwise blended current temperatures with expected trends tonight.
Still expecting lows tonight ranging from the upper 40s northwest to
upper 50s James Valley.
&&
.SHORT TERM...(This evening through Tuesday)
Issued at 224 PM CDT Mon Aug 13 2018
Latest radar imagery continues to show post frontal showers and
isolated thunderstorms northwest through north central. Surface
cold front now into Jamestown, and will linger across the southern
James River Valley this evening before stalling over northeastern
South Dakota tonight. Weak CAPE north with little or no shear will
maintain mostly rain showers and non-severe isolated thunderstorms
northwest into north central this afternoon. Post frontal clouds
are now shifting into south central North Dakota this afternoon,
and there is a slight chance of a shower late this afternoon/early
evening. However, there is a better chance for showers/thunderstorms
to redevelop later this evening/tonight across the James River
Valley. The CAMS`s have been consistent with this idea since this
morning, in developing an area of shower and thunderstorms between
04z and 10z Tuesday. Frontogenetical forcing with decent lapse
rates and large scale ascent per NAM/GFS will set the stage for
precipitation development. Although some strong thunderstorms are
possible, not expecting severe weather at this time. Most
Unstable/MU CAPE per NAM ranging between 250 and 750 J/KG and
deep layer shear 35kt to 40kt. The GFS has similar deep layer
shear, but no CAPE advertised,as it is shunted south and east of
the border, in closer proximity of the stalled front.
Smoky skies have shown improvement in the west this afternoon per
latest satellite imagery and surface observations. Upstream
observations into Canada also have improved. The vertically
integrated smoke forecast per HRRR shows lingering patchy smoke
mainly southern ND Tuesday. Thus, have scaled back the areas of
smoke north and west in the short term period. Cooler air finally
slides from north to south overnight along with an area of stratus
clouds The stratus per HRRR/GFS will push into the Turtle
Mountains and portions of north central ND late tonight through
mid morning Tuesday. Plenty of sunshine anticipated elsewhere for
Tuesday with highs in the 70s Tuesday across western/central ND.
.LONG TERM...(Tuesday night through Monday)
Issued at 224 PM CDT Mon Aug 13 2018
Warming in the early part of the long term period with highs
rising into the 80s Wednesday and then upper 80s to lower 90s
Thursday and Friday. Cooler air is expected Sunday and Monday.
As far as precipitation, a shortwave emerging over the Northern
Rockies will slide into southeastern Montana Tuesday night, then
across South Dakota Wednesday. Far southwestern and far south
central ND remain on the fringes of a slight chance of showers and
thunderstorms. The ECMWF maintains a stronger signature of PoPs
across the southwest and extends them into western ND Wednesday.
Did not adjust from Forecast Builder at this time which yielded
the initial solution above and goes along with the NAM/GFS
solutions. Otherwise, it remains dry over the rest of western/central
ND Tuesday night through most of Saturday. For Sunday, differences
arise on the track of our next Northern Rockies shortwave.
The GFS moves it through North Dakota with chances for showers and
thunderstorms across western/central ND Sunday; while the ECMWF
maintains a track from southeastern Montana and into South Dakota,
which advertises less precipitation Sunday. Behind the system
Monday, both models show cooler air via northwest flow. The CIPS
analog also advertises a brief cooling trend late this weekend
into early next week.
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 627 PM CDT Mon Aug 13 2018
Visibilities have improved from smoke across western and central
North Dakota and will not have reduced vsbys this TAF cycle.
Otherwise, will keep VCSH or VCTS early this evening at KMOT/KBIS
with ongoing convection moving east across the state. Later this
evening will have VCTS at KJMS with expected new development of
showers and thunderstorms mainly from around 03z-10z. An area of
stratus/mvfr cigs moving south out of Canada is possible at KMOT
from around 11z-16z Wednesday...and will keep a sct deck mentioned
for now - later forecasts may determine whether that stratus deck
makes it to KMOT.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JV
SHORT TERM...KS
LONG TERM...KS
AVIATION...JV
Area Forecast Discussion
National Weather Service Denver/Boulder CO
914 PM MDT Mon Aug 13 2018
.UPDATE...
Issued at 910 PM MDT Mon Aug 13 2018
The following are changes made to the 1st period forecast grids.
First, have trended dew points on the plains upward overnight.
Since 00z, dew points at several reporting site east of a Greeley-
to-Elbert Line have risen 6-10 deg F. It`s possible we could see
some fog forming late in the far eastern zones. This rise in dew
point corresponds to a strengthening east-southeast low-level
flow. In the past hour, gusts as high as 25 kts have been
observed. This influx of moisture is expected to slow cooling,
and therefore I`ve nudged up min temps on the plains by at least a
deg or two. Lastly, the narrow north-south band of showers/
t-storms passing over south-central WY at the moment coincides
with a weak mid-level shortwave trough. At its present speed,
could see this wave and its poorly organized convection tracking
across the northeast corner of the CWA between 06z and 10z
tonight. Therefore, have added a slight chance of showers/t-storms
for this area later tonight.
&&
.SHORT TERM...(This evening through Tuesday)
Issued at 204 PM MDT Mon Aug 13 2018
A mid to upper level low, which is currently over the Oklahoma
panhandle, will begin to move northeastward tonight and tomorrow
ending its influence on the weather in Colorado. Behind it, an
upper level ridge will build over Colorado tonight which will
allow for a quiet night with any showers and storms ending in the
evening. Low temperatures will be near normal with mostly clear
skies.
Mid to upper level winds will turn northwesterly tomorrow as a
small shortwave trough will influence the CWA during the
afternoon. Ascent from this feature combined with increased
moisture and weak upslope winds will allow for a better chance of
showers and storms mainly over the mountains and urban corridor.
Mixed layer CAPE values will be around 1000 J/kg and 0-6km bulk
shear will be around 30 knots so the severe weather threat will
remain minimal. Nonetheless, a storm or two could produce severe
hail near the Cheyenne Ridge and storms elsewhere could produce
gusty winds up to 50 mph. The HRRR smoke model indicates that the
smoke will be near or above the thickness we saw today. This may
lower the amount of instability compared to what is predicted
furthermore limiting the severe threat. High temperatures will
be roughly 5 degrees cooler than today with cooler temperatures at
the low levels advecting in from the east.
.LONG TERM...(Tuesday night through Monday)
Issued at 204 PM MDT Mon Aug 13 2018
For Tuesday night into Wednesday the central ridge of high pressure
will be over the Great Basin. This will help to increase NW flow
over the northern CO ahead of an upper vort max near S. Dakota late
Tuesday. Storms will slowly dissipate over the higher terrain into
the evening hours and with modest NE mid-level flow out to the east
and southerly flow closer to the foothills will keep any convection
mainly pinned to the mountains and northern foothills. By Wednesday
afternoon a mid-level jet forms over the far NE plains in accordance
with the vort max that will drop SE into western NE and could clip
the far NE corner of the state. Specific humidity values in the 700-
500 mb range will increase slightly with model soundings showing PW
values moving above an inch on the GFS. Models show a convergence
boundary setting up over the far eastern plains as a surface low
develops over WY and pushes into CO butting up against SSE flow
over the southern and eastern plains. This northerly push could help
to keep storms out of the Denver Metro and over the mountains and
Palmer divide into the late afternoon then along the boundary in the
evening where the better instability and deep shear is forming. Flow
aloft will be decent so flooding threat is low for Wednesday. Highs
will continue to be slightly above average with temps in the upper
80s to lower 90s on the plains.
For Thursday and Friday several ridges will span the southern CONUS
reaching from the CA coast to the Gulf of Mexico coast. Models are
showing moisture increasing in the mid levels with hints of the
monsoonal moisture plume trying to resurface. Specific humidity
values will increase into Friday with model PWs climbing to well
above an inch by Friday afternoon. There will be a chance of storms
over the higher terrain Thursday with temperatures very similar to
Wednesday. However, on Friday, the upper ridge will be far enough
east and west to allow for increased moisture intrusion and greater
storm coverage into late Friday. Flow aloft will decrease
introducing slower storm motion and the potential for some flooding
with the stronger cells. Temperatures will be slightly cooler Friday
with highs in the upper 80s.
For the weekend, upper level NW flow will increase with an
approaching wave. PW values will remain high over the region with
increased chances of storms over the plains bringing moderate to
heavy rain and hail Saturday and Sunday. Temperatures will be
cooler starting Sunday and into next week with a cold front and
upper trough possible by Monday.
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 910 PM MDT Mon Aug 13 2018
VFR conditions are likely at Denver area air terminals for the
remainder of the night. However, lingering smoke emanating from
several large western fires will probably continue to impact
arrival rates. East-northeast winds of 7-14kts will gradually
turn southeasterly, then southerly after 07z tonight and remain
about the same speeds.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
UPDATE...Baker
SHORT TERM...Danielson
LONG TERM...Bowen
AVIATION...Baker
Area Forecast Discussion...Updated
National Weather Service Billings MT
938 PM MDT Mon Aug 13 2018
.UPDATE...
Upper trof to the NW will slowly make its way SE overnight and
into Tuesday. Associated jet and upper dynamics will increase
over our southern and eastern sections overnight. This is playing
out a little slower initially than some models had progged, but
things are picking up quickly as we head into the mid to late
evening with coverage of precip expanding out of the foothills.
Adjusted PoP`s for the current trend toward this solution. Rest
of forecast in good shape. BT
&&
.SHORT TERM...valid for Tue and Wed...
Right-rear quadrant of upper jet will remain over the area
tonight, before shifting S of the area on Tuesday. A strong
shortwave will rotate into the western zones by 00Z Wednesday, and
move slowly E through the area on Wednesday. Upper ridging will
build over the region behind the wave through Wed. night.
Precipitable waters will be close to an inch over much of the area
through Tue. evening.
Upslope flow will help convection initiate off the mountains
through this evening and again on Tuesday. The dynamics and
moisture mentioned above will also support precipitation. RAP
soundings showed possible strong storms W of KBIL and around KSHR
into this evening. On Tuesday, MLCAPES were progged to be at
least 1000 j/kg and shear was favorable over KSHR and far S.
Central MT, so this area was placed in a Marginal Risk for severe
storms. Will issue an HWO for this as well as a graphic.
Will have scattered convection across the area tonight into Tue.,
then another round of convection Tue. afternoon into Tue. evening
shifting into the SE. Isolated convection will linger over the SE
Wed. morning, then the rest of the period will be dry. Not seeing
much letup in the smoke through the period based on W to NW winds
advecting in smoke from the large fires W and NW of the region.
Kept temperatures the same with highs in the low 80s on Tue. and
in the low 90s on Wednesday. Arthur
.LONG TERM...valid for Thu...Fri...Sat...Sun...Mon...
Shortwave ridging over the area on Thursday will bring mainly dry
conditions outside of some isolated showers and thunderstorms over
the mountains, and above normal temperatures. Models continue to
prog an upper trough moving through the Pac NW and into the
Northern Rockies over the weekend into early next week, with an
associated low developing over the region. While the general
solution is agreed upon, models differ on the placement and track
of the upper low. The GFS takes the low across central Montana,
while the ECMWF takes the low across northern Wyoming. The GFS is
currently the wetter of the two solutions. Regardless, shower and
thunderstorm chances look to increase through the weekend with
cooler temperatures over the area.
Highs look to range from mainly the 90s on Thursday and Friday,
cooling into the upper 70s to lower 80s for Saturday, Sunday, and
Monday. Low temperatures look to range from the 50s and 60s
Thursday night and Friday night, with lows mainly in the 50s
through the rest of the long term. STP
&&
.AVIATION...
Isolated showers and thunderstorms will spread eastward along the
mountains/foothills and nearby areas this evening, increasing in
coverage as they move onto the plains overnight. Local MVFR
conditions are possible under the heaviest showers/thunderstorms.
Areas of smoke will continue to restrict visibility between 5 and
10sm at times, particularly impacting slant range visibilities.
Otherwise VFR conditions will prevail. BT
&&
.PRELIMINARY POINT TEMP/POPS...
Tue Wed Thu Fri Sat Sun Mon
-----------------------------------------------------------
BIL 057/081 058/091 059/093 062/090 061/082 057/078 055/079
33/T 10/K 01/U 12/T 23/T 43/T 22/T
LVM 049/083 048/091 050/091 052/087 052/079 050/077 049/078
12/T 10/K 11/B 12/T 35/T 53/T 23/T
HDN 057/083 055/092 057/094 059/093 059/083 055/080 054/081
44/T 10/K 00/U 12/T 23/T 44/T 23/T
MLS 058/083 059/089 061/095 063/096 062/088 058/081 055/081
21/H 11/K 00/U 01/B 13/T 43/T 12/W
4BQ 058/083 056/088 057/094 060/094 060/087 055/080 055/082
45/T 51/K 00/U 11/B 14/T 45/T 22/W
BHK 054/081 055/087 057/093 058/093 058/087 054/079 052/081
21/H 11/K 11/U 01/U 12/T 45/T 22/W
SHR 054/082 053/088 054/091 056/089 056/082 053/078 052/080
33/T 41/K 11/U 12/T 23/T 54/T 23/T
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...None.
WY...None.
&&
$$
weather.gov/billings
Area Forecast Discussion
National Weather Service Dodge City KS
925 PM CDT Mon Aug 13 2018
.SYNOPSIS...
Issued at 251 PM CDT Mon Aug 13 2018
Upper level low pressure will continue to wobble northeastward
across the central plains through Tuesday. Very moist low level
air had advected into central and southwestern Kansas and
soundings were moist through a deep layer on up through 500mb and
beyond. In the wake of this system, a weak cold front is expected
to pass across western Kansas, with a wind shift to the north.
Another upper level system will pass southeastward across the
upper Midwest by Thursday, helping to push another weak cold front
into western Kansas by Thursday night. Over the weekend, a
stronger upper level system over the Pacific Northwest is expected
to move southeastward and approach the plains on Saturday. This
feature should pass across Kansas by Sunday and Sunday night along
with another cold front. By early next week, an upper level ridge
will develop across the southern Rockies and western high plains,
with a deep upper level system over the Great Lakes. In between
these features, cool surface high pressure ought to settle across
the high plains region.
&&
.UPDATE...
Issued at 925 PM CDT Mon Aug 13 2018
Initial round of convection has tapered off to largely stratiform
rain across much of the CWA at of 9:15 pm. The composite outflow
boundary of this evening`s thunderstorms has pressed through most
of SW KS, initiating new convective updrafts as it has progressed.
The flooding threat has abated, but it may very well be temporary.
00z NAM, HRRR and various other CAMs are showing a strong signal
for strong thunderstorm redevelopment overnight, starting around
midnight and continuing well into Tuesday morning. 00z NAM deepens
the closed low to near 580 dm near Hays by 7 am, with vort maxima
swinging around its backside expected to dynamically force more
convection, despite depleted surface based CAPE. We are concerned
about a threat for flooding during the midnight - 10 AM Tuesday
timeframe, with such strong model consensus on vigorous convective
redevelopment. Increased pop grids some more and included heavy
rain wording across mainly the eastern 1/2 of the CWA, where the
flooding risk appears highest. Obviously, areas that have already
received heavy rain today are most at risk for excessive runoff.
We will hold off on a flash flood watch for now, but will be
watching closely.
&&
.SHORT TERM...(This evening through Tuesday)
Issued at 251 PM CDT Mon Aug 13 2018
Thunderstorms developed early this afternoon across parts of
southwestern Kansas near the aforementioned upper low given the
lack of capping and weak diurnal surface heating. Scattered to
numerous thunderstorms are expected through tonight, especially
from Dodge City north and east near the upper level low. Clouds
and areas of precipitation will keep temperatures on the moderate
side, with lows tonight in the mid to upper 60s and highs Tuesday
mainly in the lower to middle 80s.
.LONG TERM...(Tuesday night through Monday)
Issued at 251 PM CDT Mon Aug 13 2018
In the wake of the upper level low, warmer weather can be expected
Wednesday and Thursday with highs warming into the upper 80s to
lower 90s. The best chance of storms with the system on Thursday
will be in central Kansas closer to the upper level feature. There
are good chances of thunderstorms Saturday into early Sunday as
the next upper level system approaches from the northwest.
Temperatures will be held down by clouds and precipitation
Saturday and Sunday. Drier and even cooler air should move into
western Kansas by early next week, with lows possibly in the lower
to middle 50s by Tuesday morning.
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 500 PM CDT Mon Aug 13 2018
Complicated TAF issuance with scattered showers and thunderstorms
expected to impact aviation through Tuesday morning, along with
some lower ceilings to consider. Weak closed low will move little
over western Kansas through 12z Tue. Models show showers and
thunderstorms becoming numerous starting around 06z Tue, impacting
DDC/HYS through 12z Tue. GCK/LBL will be more on the fringe of the
activity, but close enough for a convective VCTS/CB mention in
those TAFs as well. TEMPO groups were included at HYS/DDC when
rain and convective impacts are most likely. Consensus of short
term models bring IFR stratus into HYS 08-12z Tue, as was
followed. Light and variable winds outside of convection. After
18z Tue, winds will increase and become north at 10-20 kts behind
the departing closed low.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 65 81 62 86 / 90 60 10 0
GCK 65 82 60 87 / 70 30 0 0
EHA 61 87 61 90 / 40 10 0 10
LBL 64 86 61 89 / 50 30 0 0
HYS 66 77 62 84 / 90 80 10 0
P28 68 84 65 87 / 80 70 40 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...Turner
SYNOPSIS...Finch
SHORT TERM...Finch
LONG TERM...Finch
AVIATION...Turner
Area Forecast Discussion
National Weather Service Houston/Galveston TX
842 PM CDT Mon Aug 13 2018
.DISCUSSION...
00z 300 mb analysis shows a strong area of high pressure over the
western Gulf with a weak upper trough over extreme West Texas. 850
mb analysis shows a weak high over LA and warming 850 mb
temperatures at CRP (up to 22 C). There were a few shra/tsra late
this afternoon and the latest HRRR shows some potential for a few
isolated storms on Tuesday. Temperatures will likely to cool to
near the dew point by 06-07z so some patchy fog is possible but
the ground is drier than yesterday so confidence in fog formation
is low. Decided to add patchy fog to the weather grids between
09-13z otherwise the rest of the forecast looks on track. 43
&&
.PREV DISCUSSION... /ISSUED 642 PM CDT Mon Aug 13 2018/
AVIATION...
VFR and dry conditions are expected through most of the taf period
with some MVFR ceilings and fog possible over the northern taf
sites during the early morning hours. Any fog or low ceilings that
develop should improve to VFR a few hours after sunrise.
11
PREV DISCUSSION... /ISSUED 318 PM CDT Mon Aug 13 2018/
SHORT TERM [Today Through Wednesday Night]...
Radar shows a couple of isolated showers over Waller County.
These showers look to be forming on a moisture gradient with moist
air to the east and drier air to the west. SPC Mesoanalysis of
theta-e shows this gradient well with an area of moisture
convergence. Overall the atmosphere remains more subsident than
ascending so the general trend will be for these showers to
dissipate over the next hour or two. GOES 16 precipitable water
imagery shows values around 1.2 to 1.7 with a north/south gradient
of higher values to lower values. This drier air should also
limit shower/thunderstorm activity the rest of the event
especially along the coast.
Analyzing the upper levels, 500mb analysis shows some weak
ridging aloft over the NW Gulf with the upper low over SW Kansas.
The expectation is for the ridge to expand over much of Texas
through mid-week with the upper low lifting into the Plains and
weakening. This should allow for subsidence to expand over the
area and keep thunderstorm activity from forming. Forecast will
basically go with 10 to 20 PoPs with maybe a shower or two if
there is enough moisture. Higher moisture does not look to return
to the area until Wednesday through the end of the week.
LONG TERM [Thursday Through Monday]...
Thursday into the weekend there looks to be a rise in moisture
with precipitable water values getting up to 1.6 to 1.9 inches.
This should provide enough buoyancy for convection each day
although none of it will be particularly organized. Ridging aloft
may break down enough to better support thunderstorm activity over
the weekend. There is really no one signal indicating higher
thunderstorm chances for one particular day. Forecast will go with
mainly 20 to 40 PoPs which will be close to climo. Also the
forecast will go with higher rain chances for the eastern portions
of the area with lower PoPs or a dry forecast back to the west
and southwest. Rainfall amounts will range from 0 to maybe a
quarter inch depending upon how much shower activity develops.
What rainfall did occur last week should have plenty of time to
dry out and those that did not get much rain will likely see
abnormally dry and moderate drought areas expand.
Overpeck
MARINE...
Winds to remain generally light/occasionally moderate these next few
days as an upper level ridge of high pressure remains over the area.
Short-range models indicating isolated showers will be possible over
the western half of the marine zones around sunrise tomorrow, but we
should remain dry/quiet the rest of the day. Winds could briefly see
SCEC criteria overnight as well. This overall pattern will remain in
place the rest of the week. 41
&&
.PRELIMINARY POINT TEMPS/POPS...
College Station (CLL) 96 74 96 75 96 / 10 0 10 0 10
Houston (IAH) 95 77 94 77 94 / 10 0 10 0 20
Galveston (GLS) 91 82 91 82 91 / 10 0 10 10 20
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...NONE.
&&
$$
Discussion...43
Area Forecast Discussion
National Weather Service Jacksonville FL
935 PM EDT Mon Aug 13 2018
.UPDATE...
A weak sfc trough oriented southwest to northeast across the
forecast area provided a focus for showers and storms late aftn and
evening. A sharp gradient in moisture noted in RAP and GOES analyses
with PWATs of about 2.15 inches over northeast FL and tapering off
to about 1.5-1.6 inches near Hazlehurst. With loss of heating...most
of the showers and storms have dissipated with lingering showers and
a few t-storms expected rest of tonight. Have lowered POPS to less
than 40 percent rest of tonight with best chance for new development
in the couple of hours over the southeast zones. After midnight,
models suggest inland northeast FL will see an uptick in a low
chance of new convection given mid level troughing and abundant
moisture in the area, so planning to leave some POPs in for areas
west of Highway 301 for later tonight. Lows in the lower to mid 70s.
&&
.AVIATION...Prevailing VFR expected through the night but can`t
rule out brief period of MVFR cigs or vsby from about 06z-15z due to
abundant moisture and wet grounds from recent rains, especially
around GNV. Another round of showers and storms expected on
Tuesday...mainly during the aftn and early evening so VCTS is in
place at this time.
&&
.MARINE...No significant changes to the forecast with prevailing
southwest winds overnight near 10-15 kt and seas around the 2-4 ft
range, dominated by wind waves with periods of 4-5 seconds.
Rip Currents: Low risk anticipated through Tuesday due to low surf
heights and minimal ocean swell conditions.
&&
.PRELIMINARY POINT TEMPS/POPS...
AMG 73 92 72 92 / 30 40 10 40
SSI 76 88 78 89 / 30 40 40 40
JAX 74 91 73 91 / 30 70 30 40
SGJ 75 89 76 89 / 40 60 30 40
GNV 73 89 72 91 / 20 60 10 40
OCF 72 89 72 91 / 30 50 20 40
&&
.JAX WATCHES/WARNINGS/ADVISORIES...
FL...None.
GA...None.
AM...None.
&&
$$
Shashy/Enyedi/Bricker
AREA FORECAST DISCUSSION
National Weather Service Jackson KY
1057 PM EDT Mon Aug 13 2018
.UPDATE...
Issued at 1057 PM EDT MON AUG 13 2018
Forecast is still on track, and only minor adjustments were made
to blend late evening obs into the forecast.
UPDATE Issued at 901 PM EDT MON AUG 13 2018
Only very isolated showers remain, with no where near enough
coverage to justify even a 20% POP. Away from dying showers, skies
were mostly clear. In light of this, have done an overall
reduction in forecast sky cover for tonight.
&&
.SHORT TERM...(This evening through Tuesday night)
Issued at 414 PM EDT MON AUG 13 2018
Current surface observations show a slow moving boundary to the
southeast of Kentucky approaching the east coast. Radar has picked
up on some isolated showers this afternoon, but shower activity will
dwindle this evening. Isolated storms are also possible in the far
east until early this evening as well. Upper level ridging and
surface high pressure will then begin to take hold into Tuesday,
bringing drier conditions to eastern Kentucky. The primary concern
will be locally dense fog in the river valleys towards dawn
Tuesday morning. There is also the potential for dense valley fog
tomorrow night as well.
The HRRR has had a decent handle on the timing and relative
location of the isolated showers this afternoon. Therefore, have
used the HRRR as a baseline for PoPs this afternoon into early
this evening. Did include a bit more of the northern counties as
well due to recent radar trends of some isolated showers to our
north. With upper level ridging and surface high pressure setting
up for Tuesday, stuck with guidance for temperatures through the
short term. High temperatures will generally be in the mid 80s
with low temps in the mid 60s.
.LONG TERM...(Wednesday through Monday)
Issued at 414 PM EDT MON AUG 13 2018
There is good model agreement to start the long term portion of the
forecast, but agreement and confidence in the details of the
forecast decrease as we move into the weekend. For Wednesday morning
both the GFS and ECMWF show surface high pressure will be centered
over the central to southern Appalachians with mid/upper level
ridging through the OH valley. A mid/upper level short wave trough
and associated surface low will be over the eastern plains. The
pattern will be fairly progressive with the upper level short wave
trough shifting east and a surface warm front advancing towards the
area on Wednesday.
The short wave trough looks to dampen out as it moves northeast
towards the Great Lakes on Thursday as a second short wave trough
advances east from the northern Plains. At the surface a cold front
will move towards the area on Thursday, but as the initial upper
level wave damps out the front will slow and will still be northwest
of the area on Friday. The advance of the second short wave trough
may result in the cold front pushing on through the area over the
weekend, but this is uncertain. It does appear that even if the
front pushes south of the forecast area this weekend it will stall
and will likely shift back north by early next week.
For sensible weather the rather active pattern will result in daily
chances of showers and thunderstorms, but confidence in the
precipitation forecast is fairly low. There is higher confidence in
the general temperature forecast with temperatures remaining fairly
close to seasonal normals through the period.
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
ISSUED AT 901 PM EDT MON AUG 13 2018
A few showers lingered over extreme eastern KY at the start of the
period, but continued on a decline and should be gone shortly. Fog
will develop in valleys again tonight, and grow in depth and
breadth through sunrise. It is expected to again affect TAF sites
with IFR or worse conditions overnight into early Tuesday morning.
Outside of the fog, VFR conditions will prevail. Winds will be
light.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...HAL
SHORT TERM...CGAL
LONG TERM...SBH
AVIATION...HAL
Area Forecast Discussion
National Weather Service San Francisco Bay Area
439 PM PDT Mon Aug 13 2018
.SYNOPSIS...Temperatures will be near to slightly below seasonal
averages through midweek as a modest marine layer and onshore flow
persist over the region. High pressure is then forecast to rebuild
toward the West Coast late in the week and into next week bringing
warmer temperatures to the interior.
&&
.DISCUSSION...as of 01:22 PM PDT Monday...The deepening marine
layer, increased onshore flow and cooler air mass aloft have
resulted in more coastal cloud cover and cooler conditions region-
wide. Temperatures are running a few to as much as 10 degrees F
cooler compared to this time yesterday with the greatest
difference being in places such as Livermore and Hayward. In
addition, stratus that developed overnight has retreated to the
coast with many locations such as San Francisco and Monterey still
under cloud cover. These conditions are forecast to change very
little through midweek with temperatures at or slightly below
seasonal averages. May even see patchy coastal drizzle develop
overnight with low clouds spreading back inland into the valleys.
Periods of increased mid/upper level moisture are also forecast to
advect northward across the region and result development of high
clouds. At this time, sufficient moisture and instability for high-
based convection appears to stay inland and to our north. However,
will closely monitor the potential for any convection in the coming
days.
Upper level high pressure is then forecast to strengthen over the
Desert Southwest and build toward the California coast late in the
week. As a result, the marine layer will likely become more
compressed and onshore flow will weaken. 850 MB temperatures will
also be on the increase and result in a warming trend for interior
locations. The end result, more widespread 80s and 90s are likely
for the interior with our warmest locations across the region
reaching the 100 degree F mark. Meanwhile, coastal areas are likely
to remain seasonably cool with periods of overnight/morning low
clouds and patchy fog. Overall, dry weather conditions are likely to
persist through the forecast period.
&&
.AVIATION...as of 4:39 PM PDT Monday...For 00z tafs. Stratus is
currently situated along the coast and beginning to move inland as
the marine layer sits at around 1500 ft. MVFR/IFR conditions are
expected overnight and into the morning hours at most locations.
Clearing is forecast tomorrow morning around 17z-18z. Latest run
of the HRRR smoke forecast shows increased near surface and
vertically integrated smoke overnight and through much of the day
tomorrow. This will likely create slant range visibility issues.
Breezy winds will continue into the evening before diminishing in
the overnight hours. Expect onshore winds to increase again by
tomorrow afternoon, especially for KSFO.
Vicinity of KSFO...VFR/MVFR with BKN cigs currently over the
airport. IFR cigs are expected to prevail starting late tonight
and lasting through around 17z. As mentioned above, the latest run
of the HRRR smoke forecast suggests an increase in near surface
and vertically integrated smoke over the Bay Area late tonight and
through much of tomorrow. This will likely create slant range
visibility issues once the stratus clears. Winds will subside
overnight before gusty onshore winds return tomorrow afternoon.
SFO Bridge Approach...Similar to KSFO.
Monterey Bay Terminals...Stratus has already begun to intrude into
the Monterey Peninsula and is starting to move into the Salinas
Valley. Cigs are a bit higher to start off the late afternoon at
around 1300 ft, but are expected to lower to IFR/LIFR overnight.
Generally light winds through the period.
&&
.MARINE...as of 02:30 PM PDT Monday...Lighter northwest winds
offshore today as the pressure gradient weakens. Locally breezy to
gusty winds will continue to prevail along the coast especially
along the Sonoma coastline and south of Point Sur. Weak mixed
swell overall with a longer southerly swell component.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
.Tngt...SCA...Pt Arena to Pt Reyes 0-10 nm until 9 PM
SCA...Pigeon Pt to Pt Pinos 0-10 nm until 9 PM
SCA...Pt Pinos to Pt Piedras Blancas 0-10 nm until 2 AM
&&
$$
PUBLIC FORECAST: RGass
AVIATION: AS
MARINE: DRP
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Area Forecast Discussion
National Weather Service Mount Holly NJ
1019 PM EDT Mon Aug 13 2018
.SYNOPSIS...
A weak front will move little through Tuesday as weak surface
lows move through the northern Mid-Atlantic along it. The front
will move offshore Wednesday. Low pressure will move from the
Great Lakes on Thursday to New England and adjacent southeast
Canada on Saturday. An attendant cold front will progress
through the region Friday night and Saturday but is expected to
stall near or just south of the area through early next week.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
1015 pm mesoscale update: Flash flood watch has been dropped as
convection is clearly on the downward trend in the past hour.
Will reevaluate potential for additional flooding tomorrow
before determining if another watch is needed.
930 pm mesoscale update: Storms to the west/northwest of Philly
have exhibited occasional/brief downburst signatures as seen on
TPHL. Have issued several severe thunderstorm warnings for these
storms based on these signatures and the very saturated soils
(making trees especially susceptible to falling in strong
winds). Recently, outflow has spread eastward from the cells, so
expect general weakening in the next hour or two. Though these
storms are progressing reasonably quickly, have seen a few
reports of renewed flooding in the usual poor-drainage spots in
Chester and Montgomery Counties. Overall forecast is in good
shape for now. No changes to the flash flood watch yet given
ongoing convection, but the threat is diminishing with time
tonight.
730 pm mesoscale update: Showers are initiating in Berks and
Montgomery Counties as storms and resultant outflow from central
Maryland propagate into south-central PA and the Eastern Shore
of Maryland. The showers in southeast Pennsylvania may not move
much, so locally heavy rainfall may occur. However, the cores
are rather weak and do not have a history of lasting more than
about thirty minutes before dissipating. Nevertheless, these are
developing in very sensitive areas (i.e., saturated and/or
flooded), so will be monitoring closely for additional flood
potential this evening. Meanwhile the storms near/just west of
Chesapeake Bay weakened considerably once reaching the bay, but
outflow will spread east through Delmarva this evening. Winds to
49 mph occurred at Tolchester Beach as the outflow passed, and
gusts to 40 mph or so may occur through northern/central
Delmarva during the next hour.
515 pm update: Updated PoPs across the area for the evening
hours. Convection in central Maryland is expected to progress
to the Eastern Shore during the next few hours. Convection-
allowing models indicate (to varying degrees) these storms will
gradually diminish after sunset, but this process could be slow
given the high moisture content of the air and associated
slowing effects on diminishing instability. Additionally,
convection currently in central PA suggests that the environment
may be recovering sufficiently for subsequent development
farther south and east into south-central/southeast
Pennsylvania before sunset. Starting to see some radar echoes in
Berks County, indicating this threat may be increasing. The
HRRR gives some indication of this, though it is notably not
handling convection in general well this afternoon.
Also made some adjustments to temperature/dew
point grids through the evening hours, as current readings were
higher than forecast in southern New Jersey and portions of
Delmarva.
Previous discussion...
Several flood warnings remain in effect across the area as a result
of the heavy rain that fell this morning (5-8 inches in some spots).
Please follow detours and do not drive around barricades. Turn
Around, Don`t Drown!
An upper level closed low slowly moves across the region tonight.
Meanwhile, at the surface, low pressure will continue to move along
a stalled boundary and up our coast this evening.
Scattered convection is occuring in the forecast area, especially
across parts of the region that have been able to see some sunshine
today. While the storms are moving, there is not a lot of low across
the region and this means the storms will move slowly, if at all.
The slow nature of the storms combined with the high PWATs across
the region means that the storms will be efficient rainmakers and
heavy rain will fall. As the sun sets, we should see storms diminish
in coverage as the instability is largely driven by surface heating
this afternoon and evening. Energy will continue to rotate around
the upper low and we could see some showers continue through the
overnight period as a result. With the wet antecedent conditions and
keeping in mind that a good deal of rain fell across portions of the
area this morning, we have kept the Flash Flood Watch in place
through tonight.
Model shows that we could see some clearing tonight across the
region. With light winds and a lot of low level moisture in place,
some fog may develop.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH 6 PM TUESDAY/...
The upper low will start to move slowly to the northeast on Tuesday.
At the surface, the stalled frontal boundary will move little but
should make a slight shift towards the coast. Another wave of low
pressure is forecast to move along this boundary, bringing in
another round of convection and showers through the day. Highs will
generally be in the 80s across the region, with some 70s across the
southern Poconos and parts of northwest New Jersey.
&&
.LONG TERM /TUESDAY NIGHT THROUGH MONDAY/...
With a plethora of short-term concerns, spent little time on the
long-term forecast today. In general, the details have not
changed much for the rest of the week into the following
weekend.
The midlevel trough plaguing the Northeast early this week will
be ejecting into the Canadian Maritimes and offshore the New
England coast on Tuesday night and Wednesday. Lingering chances
of precipitation Tuesday night (especially offshore and in the
northern CWA) will decrease with time. Kept PoPs out of the
forecast Wednesday, but I am a little concerned about an
upstream (weak) vort max moving southeastward into southern New
England. The 12Z NAM hints at some convection breaking out
during the day, though it looks like the most favored locations
for such convection are north of the area. Nevertheless, would
not be surprised if we need to add some PoPs to areas near/north
of I-80 in later forecasts. Otherwise, the rest of the region
will see rising heights and partially or mostly sunny skies.
This spells a hot day for the area.
Shortwave ridging enters the area Wednesday night and Thursday.
Associated large-scale subsidence should allow for a dry period
and warm temperatures. Kept temperatures close to a statistical
blend, but I suspect highs will need to be nudged upward in
subsequent forecasts given observed model biases in the past.
MEX guidance is particularly warm on Thursday, with heat indices
in the upper 90s in much of the urban corridor and Delmarva.
Next system approaches the area on Friday and Friday night, with
a surface low progressing from the Great Lakes to the Northeast
during the period. A cold front will progress into the
Appalachians during the day and enter the CWA by Friday night.
Timing differences exist among the operational simulations, but
the overall evolution is reasonably similar at this time range.
Given timing of the front, convection looks to peak in intensity
west of the area during the afternoon (possibly affecting the
western CWA) and nocturnally weaken as it moves into the heart
of the region. Severe threat looks fairly low anyway given the
weak shear and CAPE profiles.
Of more concern is what happens to the front this weekend, as
there are indications it may slow to a crawl near or south of
the CWA. To varying degrees, operational models show subsequent
rounds of convection developing along the increasingly quasi-
stationary boundary. We`ve seen this scenario before (many
times) this summer, with indications another heavy rain event
may occur somewhere in the Mid-Atlantic during this time frame.
There is some consensus that the southern CWA may be most at
risk for this (in our area), but model discrepancies are large
by this point. The pattern, though, suggests that this is yet
another period to watch closely in the upcoming days.
&&
.AVIATION /02Z TUESDAY THROUGH SATURDAY/...
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG,
KILG, KMIV, KACY and surrounding areas.
Tonight...Generally VFR, but there is some potential for either
sub-VFR VSBYs (patchy fog) or sub-VFR CIGs (low stratus) after
midnight, particularly north/west of KPHL. Additionally,
monitoring storms closely northwest of KPHL, with outflow
nearing the Philly terminals at this time, and lightning cannot
be ruled out (especially at KPNE and KTTN). Winds light and
variable, but stronger near precip/outflow. Very low confidence.
Tuesday: Generally VFR, but scattered storms are expected to
develop during the afternoon. Local sub-VFR conditions possible
in proximity to showers/storms. West winds 5 to 15 kts. Moderate
confidence.
OUTLOOK...
Tuesday night: May see some remnant showers/storms north and
east of the Philly terminals, but chances should diminish with
time. There is also some potential for patchy fog. West winds
generally below 10 kts. Low confidence.
Wednesday: VFR. Winds west 5 to 15 kts. Moderate confidence.
Wednesday night and Thursday: Predominantly VFR, but there may
be some patchy fog between midnight and 8 am or so, especially
at the more susceptible sites. Light/variable winds Wednesday
night becoming southwest 5 to 10 kts on Thursday. Moderate
confidence.
Thursday night and Friday: Predominantly VFR, but increasing
chances of showers/storms through the period, with local sub-
VFR conditions possible. South to southwest winds 5 to 15 kts.
Moderate confidence.
Friday night and Saturday: A chance of showers/storms,
especially Friday night. Local sub-VFR conditions probable, and
longer-duration sub-VFR conditions possible in proximity to a
frontal passage. Southwest winds 5 to 15 kts in advance of the
front Friday evening/night becoming west or northwest behind the
front Saturday. Low confidence.
&&
.MARINE...
Sub-Small Craft Advisory conditions are expected to continue across
the area waters. A boundary across the waters has the winds in
different directions this afternoon, with northeast winds across the
northern waters and southwest winds across the southern waters.
Winds should become more southwest overnight and then pick up around
10 to 15 knots for Tuesday. Seas are 2 to 4 feet on the ocean and
around 1 to 2 feet on the Delaware Bay.
OUTLOOK...
Tuesday night through Saturday: Sub-advisory winds/seas
expected, though seas may approach advisory levels on Friday and
Saturday as a cold front approaches the region. A chance of
showers/storms Tuesday night and again Friday and Saturday.
RIP CURRENTS...
There is a low risk for the development of dangerous rip
currents today and Tuesday.
&&
.TIDES/COASTAL FLOODING...
We are expecting spotty minor coastal flooding with this
evening`s high tide. It will be due mainly to the high
astronomical tides associated with the new moon. However, the
flooding due to the tides is not anticipated to be widespread
enough to warrant another Coastal Flood Advisory at this time.
We will continue to monitor gauges closely, especially given the
heavy rainfall that has occurred today in Monmouth/Ocean
Counties.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...None.
NJ...None.
DE...None.
MD...None.
MARINE...None.
&&
$$
Synopsis...CMS
Near Term...CMS/Meola
Short Term...Meola
Long Term...CMS
Aviation...CMS
Marine...CMS/Meola
Tides/Coastal Flooding...
Area Forecast Discussion
National Weather Service Pueblo CO
308 PM MDT Mon Aug 13 2018
.SHORT TERM...(This evening through Tuesday)
Issued at 257 PM MDT Mon Aug 13 2018
Currently...Well defined upper low per high level water vap sat pix
imagery was spinning, with the center being over the TX/OK phdl/NM
region. Showers and thunderstorms were noted along the contdvd, and
were moving at a pretty good clip southward. More isold activity was
noted along the mtns/plains interface. Over the plains skies were
mostly clear, but a few more clouds were noted over the far eastern
plains. Temps at 2 pm were generally in the 80s over the plains with
70s in the valleys. Temps were in the 50s and 60s in the mtns.
Skies were hazy all areas due to the Calif smoke.
Rest of today into tonight...
Overall best chance of showers rest of this afternoon into the
early evening along the Contdvd. Guidance was showing some isold
activity developing over the far eastern plains late this
afternoon into the evening hours. Guidance also show some showers
redeveloping over the far eastern plains later tonight. The I-25
corridor east of the mtns should remain completely dry. Min temps
tonight should be in the 50s to around 60, with 30s and 40s in the
mtns/valleys. Cant rule out some 30s in the smaller valleys.
With storms moving pretty quickly southward, believe any flash flood
threat on any burn scars is low.
Tomorrow...
Upper low is fcst to lift off to the northeast with time. Some
clouds and isold showers will be possible over the far eastern
plains tomorrow. Showers and thunderstorms should be a bit more
numerous over the higher terrain during the afternoon time period.
Flow over the upper 2/3rds of the atmosphere will transition to
northwesterly so we should see some storms move off the higher
terrain onto the plains later in the afternoon, especially over the
divides. Max temps tomorrow should be 1 to 2 degrees cooler than
today.
Cant rule out some isold heavier rain in the higher terrain
tomorrow.
.LONG TERM...(Tuesday night through Monday)
Issued at 257 PM MDT Mon Aug 13 2018
Thunderstorm activity will pull southeastward Tuesday night,
focusing along the front as it drops southward. Most activity
diminishes across southern CO by midnight according to the NAM and
GFS.
Wednesday looks to be the more active day for southern CO as an
upper level trof glances through NE CO. Northwest flow aloft
increases as a result, which helps to increase deep layer shear.
Upslope flow gives way to development of lee trof/sfc low which
is progged to kick eastward across the plains. This may serve to
dry out surface dew points along portions of the I-25 corridor and
decrease CAPE a bit. However, still looks like around 1500+ J/kg
of CAPE will be be present, particularly along the Palmer and
Raton ridges as well as the southeast plains east of KLHX. This
appears to be where NamNest is painting the stronger convection.
Either way, it appears sufficient parameters will be in place to
support a severe thunderstorm threat Wednesday afternoon and
evening.
Some differences exit for Thursday as NAM holds on to some low level
moisture and instability for afternoon while GFS starts to dry
things out. With the upper ridge rebuilding deep layer shears may
decrease some which should decrease the severe thunderstorm threat.
Will carry isolated to scattered thunderstorms this day with
greatest coverage over the mountains.
Friday and Saturday look similarly active as yet another upper trof
moves by to the north, though there are some timing differences
between the ECMWF and GFS. Eventually this sends another front
through the southeast plains with the potential for another uptick
in moisture and thunderstorm chances early next week. Overall
looks like a relatively active period for thunderstorms the next
several days. -KT
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 257 PM MDT Mon Aug 13 2018
VFR conditions are anticipated during the next 24 hours at all 3 taf
sites; KPUB, KALS and KCOS. HRRR is trending drier in the low levels
later tonight so will likely not mention any lower cigs at KCOS
prior to sunrise. Winds next 24 hours should be light and mainly
diurnally driven. It is possible a -tsra may be in the vicinity of
KCOS at the end of this fcst period.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...HODANISH
LONG TERM...KT
AVIATION...HODANISH
Area Forecast Discussion
National Weather Service Tucson AZ
227 PM MST Mon Aug 13 2018
.SYNOPSIS...Isolated afternoon and evening thunderstorms can be
anticipated through Tuesday. Thereafter, an increase in moisture
will result in an upswing in thunderstorm activity Wednesday through
Thursday. Along with this upswing in thunderstorms, cooler
temperatures can be expected. More typical monsoon activity and
temperatures will return for the coming weekend.
&&
.DISCUSSION...Isolated showers and thunderstorms were developing
this afternoon across parts of southeast Arizona. Recent HRRR
solutions continued to advertise limited thunderstorm activity
through tonight. GFS model showed the upper high becoming centered
over east-central Arizona on Tuesday with the flow more
southeasterly. This shift in the flow pattern should start to advect
deeper moisture back into the area by Wednesday. Based on this
moisture advection and an inverted upper level trough moving out of
northern Mexico on Wednesday, still expect an upswing in shower and
thunderstorm activity Wednesday through Thursday. Lingering moisture
into the weekend should be sufficient to support daily thunderstorms.
Along with the anticipated increase in rain chances, models showed
cooler daytime temperatures Wednesday and Thursday.
&&
.AVIATION...Valid through 15/00Z.
Isolated SHRA/TSRA will continue into this evening and mostly
diminish after 14/04Z. Brief MVFR conditions possible with TSRA,
otherwise SCT-BKN cloud bases generally 8k-12k ft AGL. Outside of
thunderstorm gusts, expect mainly light NWLY SFC winds. The
exception will be near KSAD where winds will be 14-18 kts with
higher gusts possible. Aviation discussion not updated for TAF
amendments.
&&
.FIRE WEATHER...The pattern remains favorable for isolated
thunderstorm development areawide through Tuesday. Thereafter,
increased moisture will result in scattered showers and
thunderstorms as early as Wednesday afternoon and continuing into
the weekend with localized areas of heavy rain possible. Near or
slightly below normal temperatures will continue throughout the
forecast period. 20-ft winds will be terrain driven at less than 15
mph, except for in and around thunderstorms where strong outflows
may occur. The Gila River Valley including Safford will see slightly
elevated winds this afternoon and again Tuesday to around 15-20 mph.
in Tuesday to around 15-20 mph.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...None.
&&
$$
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