Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 07/17/18
Area Forecast Discussion...UPDATED
National Weather Service Albuquerque NM
554 PM MDT Mon Jul 16 2018
.AVIATION...
00Z TAF CYCLE
Scattered convection will continue through approximately 17/06Z
before gradually dissipating. Storms will produce brief MVFR/IFR
conditions and mountain obscurations. Drier air will move in Tuesday,
limiting afternoon and evening thunderstorm coverage to the
northwest third of the state, especially mountains.
33
&&
.PREV DISCUSSION...247 PM MDT Mon Jul 16 2018...
.SYNOPSIS...
High terrain thunderstorm activity has sprung up again this
afternoon. Storms will gradually move westward expanding over lower
elevations of central and western New Mexico. Storms over eastern New
Mexico will be more isolated and erratic in their motions. Any storm
will be capable of producing localized heavy rainfall and flash
flooding. Storm coverage trends down tomorrow through the rest of the
week, being more confined to the higher terrain. Highs will also
trend up as high pressure builds over the state, with 100s popping up
over eastern New Mexico by Wednesday.
&&
.DISCUSSION...
Another day, another round of afternoon storms forming over the
high terrain of central and western NM. A few storms have also
formed along a sfc bdry from Quay down to Roosevelt Counties. An
easterly wave is currently located over the southern periphery of NM,
setting up stronger westerly flow there, allowing storms to move
along at a somewhat decent pace. Flash flooding still remains a
concern for those areas having received rainfall in recent days. Storm
motion is much slower over the northern mtns of the state where
localized heavy rainfall and flash flooding are the main concerns
again. Have kept the Flash Flood Watch going for portions of central
and western NM, except the northern Sacramento Mtns where dry mid-
level air behind the easterly wave is working to inhibit storm
formation so far. HREF and HRRR are also not gun-ho not showing much
of anything forming there through the rest of today.
Another outflow enhanced frontal push from CO into northeast NM could
keep storms going a bit longer tonight for the northeast plains.
Otherwise, expecting storms to taper off this evening into Tuesday
morning. High pressure begins to build over the state Tuesday, with
the drier mid-level air behind the easterly wave pushing over
southwest NM. This will limit most of tomorrow`s storm activity to
the northern mtns. The ridge continues to build over the Four Corners
mid-late this week, with storm coverage trending down and high
temperatures trending up. Models have backed off quite noticeably
from yesterday, and are limiting afternoon convection to the higher
terrain. Although rainfall footprints are expected to be less, the
threat for locally heavy rainfall and flash flooding over high
terrain burn scars will remain. Highs across the state will be
several degrees above average by Wednesday, with 100s popping up over
eastern NM.
The ridge looks to slide more squarely over NM this weekend, keeping
storms limited to the higher terrain in the afternoons. Long range,
the GFS and ECMWF differ handling an embedded trough along the
northern periphery of the ridge. The GFS has it a bit stronger,
bringing more of a NW flow over northern NM. This would favor a
backdoor front sliding into eastern NM, increasing storm coverage
there early next week. Will have to monitor this as we get closer.
24
&&
.FIRE WEATHER...
An easterly wave will move to the west across southern NM this
afternoon, while a ridge of strong upper level high pressure in the
Great Basin builds eastward across western CO and northwest NM. The
mid and upper level flow between these systems will be east at
around 10 knots across central NM, and light winds aloft will
prevail across northern NM under the influence of the upper level
ridge. Winds near the surface this afternoon and evening will be
light. Deep layer moisture will remain across the region this
afternoon and evening, and scattered to locally numerous showers and
thunderstorms will develop with the greatest density of activity
across the higher terrain of northern and western NM. Flash flooding
will be possible this afternoon and evening in portions of northern
and western NM. Ventilation rates will be fair to good across most
of the region this afternoon, but will be poor to fair in portions
of northern and western NM.
The upper level ridge will expand over northern and central NM
Tuesday, as drier mid level air spreads westward across eastern and
south central NM. Warmer and drier air aloft will decrease shower
and thunderstorm activity in eastern and south central NM Tuesday
afternoon and evening. Despite warming aloft, scattered showers and
thunderstorms will develop across northern and western NM Tuesday
afternoon and evening with the continued threat of flash flooding
due to slow storm motion. Weak surface high pressure in TX Tuesday
will produce light south winds across western and central NM and
south winds 10 to 15 mph across the eastern plains. Ventilation
rates in north central and western NM Tuesday will be poor to fair
with fair to good conditions elsewhere.
There will continue to be a decrease in shower and thunderstorm
activity across most of the region Wednesday, as the large ridge to
the west becomes stronger and builds farther east across NM. The
exception will be in the northeast plains and adjacent highlands,
where a backdoor cold front is expected to increase activity
Wednesday afternoon and evening. The strong ridge will remain over
NM Thursday with less coverage of showers and thunderstorms. Little
change is expected Friday, except a backdoor cold front may increase
shower and thunderstorm activity from the northeast and east central
plains west to the central mountains. The strong upper high will
shift eastward Saturday and Sunday with recycled moisture producing
isolated to scattered showers and thunderstorms. Temperatures will
be above normal Wednesday through Sunday with minimum relative
humidity each day from the upper teens to lower 30s.
28
&&
.ABQ WATCHES/WARNINGS/ADVISORIES...
Flash Flood Watch through late tonight for the following zones...
NMZ503>506-508-510>515-521.
&&
$$
24
Area Forecast Discussion
National Weather Service Caribou ME
1150 PM EDT Mon Jul 16 2018
.SYNOPSIS...
A strong cold front will approach the region from the west
early Tuesday then cross the region later Tuesday through
Tuesday night. High pressure will build across the region
Wednesday into Thursday.
&&
.NEAR TERM /THROUGH TUESDAY/...
1135 pm Update...
Temperatures at this hour were ranging from the low to mid 60s
across downeast in areas of fog but in the mild lower 70s
across the northern half of the forecast area. Have adjusted the
forecast based on current conditions. Did back off a bit on the
chance of showers overnight based on latest HRRR and current
radar trends.
Prev discussion blo...
A southerly flow will emerge this evening and through the night.
This flow will advect a broad area of fog and stratus from the
Gulf of Maine northward to cover most of the forecast area by
later tonight. Fog will be most likely towards the coast and in
higher terrain areas, but could extend over the southern half of
the forecast area by daybreak Tuesday. Stratus will definitely
cover the entire area by later tonight. The clouds and continued
moisture advection will limit lows tonight to the low to mid
60s. The low clouds remain a big part of the story on Tuesday as
they`ll limit high temperatures and development of surface-based
instability. As a result, will not include any enhanced wording
for winds or hail in spite of the SPC marginal risk. Heavy
rainfall remains the significant concern. There is some elevated
instability that will cross the southern half of the area
Tuesday morning into early afternoon. Some storms could fire
from an H850 thermal ridge and there is a strong H850 LLJ exit
region on the back edge of this elevated instability area. Will
mention scattered thunderstorms with heavy rainfall in response.
Both surface-based and elevated convection are unimpressive in
the afternoon when PWATs and the deep warm cloud increase ahead
of the cold front. Dew points will likely be just above 70F
ahead of the cold front, an event that occurs very infrequently
here. The abundant moisture, warm cloud depth, strong LLJ,
precipitation efficiency and potential for training cells leads
to continuing mention of heavy rainfall in the northern and
western zones Tuesday afternoon. All of the area will likely
receive a much-needed half inch to an inch of rainfall, but the
area most likely to receive greater amounts appears to be
towards the Moosehead Lake region. The combination of terrain in
Piscataquis County and rainfall rates locally reaching 1 to 2
inches in 3 hours will make this area worthy of close watch
later tomorrow.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/...
A cold front will cross the region Tuesday night, reaching the
Downeast coast late. Precipitable water values of around 2.00
inches are expected in advance of the front. With the abundant
moisture and possible training showers/thunderstorms, could
still have a chance of locally heavy rain in advance of the
front Tuesday night. Shower/thunderstorm chances will diminish
in the wake of the front. The front will exit across the Gulf of
Maine Wednesday, while high pressure begins to build toward the
region. Could still have a chance of showers Downeast early
Wednesday with the exiting front, with decreasing clouds during
the afternoon. Across northern and central portions of the
forecast area, expect partly/mostly cloudy skies early Wednesday
with decreasing clouds during the afternoon. High pressure then
builds across the region Wednesday night through Thursday with
mostly clear skies. Temperatures will be at near normal, to
slightly above normal, levels Wednesday/Thursday.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
High pressure will remain across the region Friday into
Saturday, then begin to exit across the Maritimes later
Saturday. Generally expect mostly clear skies Friday/Saturday.
The return flow around exiting high pressure will bring
increasing moisture Sunday into Monday with increasing shower
chances. Temperatures will remain at near normal, to slightly
above normal, levels Friday through Monday.
&&
.AVIATION /04Z TUESDAY THROUGH SATURDAY/...
NEAR TERM: 1135 Update...
VLIFR at this hour KBGR/KBHB in low clouds and areas of fog. VFR
was occurring at the northern terminals but expect conditions
to deteriorate to IFR/LIFR by daybreak in low clouds and patch
fog.
LIFR at BHB into Tue afternoon. Remaining terminals will see
IFR restrictions, though showers may raise conditions to MVFR
at some point during the afternoon. However, embedded tstms with
locally heavy rainfall expected may keep IFR restrictions in
place through most of the day.
SHORT TERM: Generally expect MVFR/IFR conditions across northern
areas through the early morning hours Wednesday, with improving
conditions late. MVFR to LIFR conditions are expected Downeast
Tuesday night. Showers, with a slight chance of thunderstorms
along with locally heavy rain, are expected in advance of the
cold front Tuesday night. MVFR/IFR conditions are expected
Downeast early Wednesday, with VFR conditions developing during
the afternoon. VFR conditions are expected across northern areas
Wednesday. VFR conditions are expected across the entire region
Wednesday night into Saturday.
&&
.MARINE...
NEAR TERM: Fog continues through Tuesday. Winds and seas will
pick up ahead of cold front later Tuesday, but the stability of
the situation does not support an SCA due to winds. Long period
south swell could reach nearly 5 ft by late Tuesday.
SHORT TERM: Generally expect conditions to remain below small
craft advisory levels Tuesday night through Thursday. However,
conditions could approach small craft advisory levels early
Tuesday night. Visibilities will be be reduced in showers and
fog, along with a slight chance of thunderstorms, Tuesday night.
Showers will persist early Wednesday.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...Dense Fog Advisory until 8 AM EDT Tuesday for MEZ029-030.
MARINE...None.
&&
$$
Near Term...Duda
Short Term...Norcross
Long Term...Norcross
Aviation...Duda/Norcross
Marine...Duda/Norcross
Area Forecast Discussion
National Weather Service Cheyenne WY
206 PM MDT Mon Jul 16 2018
.SHORT TERM...(This evening through Wednesday night)
Issued at 200 PM MDT Mon Jul 16 2018
Convection has been confined mainly to the Snowy Range early this
afternoon with some weak showers persisting farther north. Satellite
showed an approaching shortwave with some convection developing over
western Wyoming. Expect showers and storms to spread into the western
parts of the CWA by late this afternoon and move over the plains
through much of this evening. Best instability looks to be over northern
parts of the CWA and expect this area to get the strongest storms,
mainly this evening as suggested by the HRRR and NAM. Showers and
storms likely to persist through tonight over the Nebraska Panhandle
as the shortwave passes by.
Similar pattern across the area Tuesday with the next shortwave likely
to kick off another round of convection especially over the plains.
Some strong to severe storms possible again with instabilities from
1500-2500 J/kg progged over the plains Tuesday afternoon and evening.
Drier air then moves into the area Tuesday night with monsoonal moisture
being shunted to the south with a warm and dry day Weds.
.LONG TERM...(Thursday through Monday)
Issued at 200 PM MDT Mon Jul 16 2018
Center of upper ridge west of the Four Corners will gradually drift
east and amplify over the Rockies and High Plains through Saturday.
Upper shortwave trough tracking east across the Northern Rockies and
Plains will suppress the ridge to the south Sunday and Monday. After
a rather warm Thursday, a dry frontal passage late Thursday will bring
slightly cooler temperatures Friday. A warm up returns Saturday as
700mb temperatures rise to near 20 deg Celsius. A lee surface trough
sets up across the high plains Saturday afternoon, which may focus
isolated late day convection, as well as over the Snowy/Sierra Madre
mountains. Another front pushes southeast across the CWA Sunday
afternoon, with focus for widely scattered convection along and south
of I-80 in southeast WY. High temperatures Monday will be closer to
seasonal normals with highs in the 80s.
&&
.AVIATION...(For the 18Z TAFS through 18Z Tuesday morning)
Issued at 1147 AM MDT Mon Jul 16 2018
Residual MVFR CIG at KSNY will become VFR by 20Z. Few SHRA/TS have
formed during the morning along a weak outflow boundary across east-
central WY. Convection will redevelop over the higher terrain of
southeast WY by mid-afternoon, and intensify while spreading east
during the late afternoon and evening. With the exception of KRWL.
have VCTS after 21Z at KLAR and KCYS, with VCTS or prevailing -TSRA
for the NE Panhandle after 06Z. Isolated strong/severe TSRA with
hail, strong winds and turbulence will be possible east of the
Laramie Range after 22Z.
&&
.FIRE WEATHER...
Issued at 200 PM MDT Mon Jul 16 2018
Fire weather concerns should stay fairly low through the week with warm
conditions continuing. There will be scattered to numerous showers and
thunderstorms into this evening, and again on Tuesday as a couple
disturbances pass across the region. Drier conditions are then expected
across the area Wednesday through Friday as monsoonal moisture is cut
off for a time.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...None.
NE...None.
&&
$$
SHORT TERM...RE
LONG TERM...MAJ
AVIATION...MAJ
FIRE WEATHER...RE
Area Forecast Discussion
National Weather Service Wilmington NC
933 PM EDT Mon Jul 16 2018
.SYNOPSIS...
Moisture will continue to increase ahead of a cold front that
will arrive Tuesday night. After a break in the showers around
Thursday, the front and its moisture will return on Friday and
linger over the weekend.
&&
.NEAR TERM /THROUGH TUESDAY/...
As of 930 PM Monday...One cluster of thunderstorms that has
recently developed across western Williamsburg County apparently
didn`t get the memo that it was supposed to wait a few more
hours. The latest HRRR shows some showers developing across
this area but not until 03Z/11 PM EDT. Convection is still
anticipated to be most numerous near the coast and offshore
overnight, following better low-level instability near the
85-degree ocean water. Forecast PoPs through 12Z/800 AM EDT
range from 20-30 percent along the I-95 corridor to 50-70
percent along the coast, highest in the Myrtle Beach to Cape
Fear/Bald Head Island corridor and offshore.
Severe weather is not expected overnight, but locally heavy
rainfall could certainly develop given increasing precipitable
water values, slow cell motion, and nearly 13,000 feet between
the LFC and the freezing level supporting efficient warm-cloud
coalescence processes.
Discussion from 700 PM follows...
Changes with the near-term portion of the forecast are
primarily concerned with pushing back the beginning of PoPs by
several hours based on latest radar and HRRR/GFS model trends.
It still appears reasonable for showers to begin blossoming
along the SC coast and just offshore around midnight, spreading
northeastward toward Cape Fear before daybreak. Weak lapse rates
and a dry mid-level airmass are currently impediments to
convection, however as southwesterly 850-500 mb winds increase
overnight moisture should increase from the west where
precipitable water values are near 2.2 inches across western
South Carolina.
Interior portions of the eastern Carolinas don`t appear quite
as likely to receive measurable rain overnight due to relatively
stable thermodynamic conditions and I`ve trimmed PoPs back to
20-30 percent here. No changes have been made to overnight low
temp forecasts, still anticipated to reach the lower to mid
70s. -TRA
Discussion from 300 PM follows...
There will be decent mid to upper level support and moisture
returning as a shortwave rotates through the Southeast, over our
local forecast area tonight and deep SW flow develops. The
convection upstream this afternoon, as seen by radar, has been
enhanced by shortwave and deeper level moisture. Expect this to
reach into our area through this evening and into tonight.
Clouds have kept heating slightly moderated so far today with
temps reaching into the 80s and the best shortwave energy has
been delayed keeping a very moist column tonight with smaller
CAPE values showing mainly elevated instability and still some
warmer air in the mid levels, but heading into Tues morning,
instability will increase with a deep SW flow and pcp water
values up near 2.3 inches. Convection will be especially
enhanced over the nocturnally favored adjacent waters overnight
as the shortwave energy rotates around from the S-SW. Therefore
kept best chc of pcp along the coast overnight into early Tues.
The intensity of convection should diminish some as heating of
the day cuts off, but expect clouds and pcp through the period.
WPC shows a marginal risk for excessive rainfall across the
Eastern Carolinas with a slight risk right along the tip of Cape
Fear and just north.
The column dries somewhat through Tues aftn as flow veers to
the W-NE as shortwave reaches the coast, but still shows 1.9
inches of pcp water. May see a lull in convection at this time,
but kicks back up again later Tues ahead of an approaching cold
front. Overall, expect clouds and increased chc of pcp through
much of the period. Winds will remain light through much of
tonight, but will increase out of the SW on Tues as gradient
tightens between Bermuda High to the east and approaching cold
front. Expect some stronger storms possible as moisture pools
and heights fall ahead of cold front through later on Tues.
Clouds and pcp will moderate the temps through the period, but
overall expect a humid air mass in place through the period with
less of a diurnal swing with overnight lows in the 70s and mid
80s to around 90 for highs on Tues.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH WEDNESDAY NIGHT/...
As of 300 PM...Moisture will surge ahead of a mid-level trough
and cold front that will approach the forecast area Tuesday
night. A deep layer of synoptic lift ahead of the front, along
with precipitable water values of up to 2.3 inches will lead to
numerous showers with potential for thunder Tuesday night. WPC
has drawn a slight risk of excessive rainfall across the Cape
Fear region, and a marginal risk elsewhere across the forecast
area, through the Tuesday night time frame.
The front will make it into the northwestern tier of the CWA by 12Z
Wednesday, then slowly make its way through Williamsburg and
Georgetown counties Wednesday evening. Cloud cover Wednesday will
limit instability to a point, however areal coverage of showers and
thunderstorms should increase with daytime heating. PoPs will
decrease Wednesday night as significant drying occurs in the 700-300
mb layer.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
As of 300 PM Monday...Frontal moisture sinks far enough south and
east that most of the area may see a break in the otherwise rain-
laden week. Some light rain could linger near the coast due to its
proximity to the stalled front. Mid level trough in the Great Lakes
starts reloading on Friday and the front and its associated
moisture/rain should return (quite heavily according to the ECMWF,
more tempered and only coastal according to GFS-the former now the
favored solution). The confluent/digging nature of this upper wave
will keep us in the deep moisture as well as the warm sector of the
surface system. Rain chances will persist as will the chance for
some appreciable rainfall amounts. Despite the extensive cloud cover
for most of the period temperature guidance is showing temperature
deviations from climatology as being minimal.
&&
.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
As of 00Z...Time height shows fairly dry air aloft at present, with
no convection expected this evening. After midnight, deep moisture
starts to advect in from the southwest, with the atmosphere becoming
saturated all the way to 400 mb. Cape will only be moderate on
Tuesday due to the cloud cover, and thunder will be limited to the
afternoon hours. Showers are a good bet throughout the day.
Visibilities could go below 2 miles briefly in the heavier
convection with high precipitable water values. Ceilings will likely
bounce around, but should be predominately MVFR. Southwest flow
through the forecast period.
Extended Outlook...Occasional MVFR to IFR conditions due to
scattered to numerous showers and TSTMs.
&&
.MARINE...
NEAR TERM /THROUGH TUESDAY/...
As of 930 PM Monday...No significant changes are needed to wind
or wave forecasts overnight. I anticipate scattered showers and
a few t-storms to develop near the South Carolina coast in the
next several hours, spreading northeastward toward Cape Fear
before daybreak Tuesday. -TRA
Discussion from 300 PM follows...
Quiet conditions continue across the coastal waters with winds
under 10 kts and seas under 3 ft. Although somewhat variable
winds right now, a southerly flow will develop and increase
through Tuesday as gradient tightens between Bermuda High to the
east and approaching cold front from the NW. Expect S to SW
winds 10 to 15 kts by early Tues and increasing to 10 to 20 kts
through Tues aftn. This will push seas up from less than 3 ft
through much of tonight to 3 to 5 ft by Tues aftn Seas with some
6 fters possible by the end of this period. Shorter period wind
waves will begin to mask a longer period fading swell.
SHORT TERM /TUESDAY NIGHT THROUGH WEDNESDAY NIGHT/...
As of 300 PM...Southwesterly flow ahead of a cold front Tuesday
night will reach 15-20 knots, then diminish Wednesday as the
boundary moves across the waters. Seas are expected to remain in
a solid 3-5 ft range Tuesday night, with some 6 ft seas not out
of the question around Frying Pan Shoals and the outer waters
from Cape Fear northward Tuesday evening.
Numerous showers and thunderstorms are expected along and ahead of
the front, which will slowly make its way south of the South Santee
Wednesday night. A postfrontal northeast surge of 15-20 knots will
occur Wednesday night.
LONG TERM /THURSDAY THROUGH SATURDAY/...
As of 300 PM Monday...No significant increase in wind or waves
through the period and we shall stay below advisory or headlines
criteria. There is still some uncertainty however regarding
wind direction. The period will start with a front to our south;
one that is eventually slated to return northward. As this
happens the flow will veer from easterly. The current forecast
has this happening a bit slower than previously with the veering
not happening until Thursday night into Friday.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...None.
NC...None.
MARINE...None.
&&
$$
SYNOPSIS...MBB
NEAR TERM...TRA
SHORT TERM...CRM
LONG TERM...MBB
AVIATION...DL
Area Forecast Discussion
National Weather Service Marquette MI
622 PM EDT Mon Jul 16 2018
.SHORT TERM...(This evening through Tuesday)
Issued at 407 PM EDT MON JUL 16 2018
WV imagery and RAP analysis indicated a mid/upper level low just
west of James Bay resulting in cyclonic wrly flow through the nrn
Great Lakes. At the surface, gusty west winds of 20-25 mph (higher
gusts of 30-35 mph over the Keweenaw) prevailed between 1018 mb
high pres into the nrn plains and a 1002 mb low at the south end
of James Bay. Although Much drier air has moved in with dewpoints
into the mid 40s, under sunny skies temps have still climbed into
the upper 70s with low 80s in downslope locations. Cooler air
behind a secondary cold front was moving into ne MN and nrn Lake
Superior.
Tonight, dry conditions and mostly clear skies with diminishing
winds will result in good radiational conditions. However, there
may be enough low level winds to maintain some mixing, especially
over the est half. Satellite trends and models fcst RH suggest
clouds may increase over the n cntrl and east late which will also
keep temps from falling off as far. Nevertheless, expect temps to
drop into the upper 40s interior west to mid to upper 50s south
central in continued nw downslope flow.
Tuesday, any morning clouds should dissipate by midday.
Sunshine/mixing with 850 mb temps into the 8C-10C range will support
highs in the mid and upper 60s north to low and mid 70s south.
.LONG TERM...(Tuesday night through Monday)
Issued at 311 PM EDT MON JUL 16 2018
High pressure pushing east across the Upper Great Lakes Tuesday
night into Thursday this will favor the continuation of less humid
and more seasonable temperatures. Tuesday night has the potential to
be a rather chilly night inland from the Great Lakes due to strong
radiational cooling and light winds. Some bias-corrected data are
hinting at some locations possibly dropping into the upper 30s in
spots. Confidence is not high as to whether or not temperatures will
drop that low as it will depend on how low dew points get during the
day on Tuesday. As surface ridging crests the Upper Great Lakes on
Wednesday, expect a five star weather day with seasonable
temperatures, comfortable humidity levels, and light winds with
ample sunshine!
Wednesday night through Thursday, low-level moisture and cloud cover
will gradually increases as surface ridging slides southeast of the
region and return flow develops across the Middle/Upper Mississippi
Valley as a shortwave trough begins to eject out of the Plains
towards the Great Lakes region. Ahead of this trough, 850mb
temperatures will warm slightly, so expect temperatures to gradually
warm back up into the lower 80s on Thursday.
Late Thursday through early Sunday, the above mentioned shortwave
will gradually move into the region and slow it`s eastward
progression as it becomes cutoff low later in the week. What this
means is we`re looking at increased chances for precipitation during
this time period, as well as cooler conditions. As for precipitation
amounts, there is quite a bit of uncertainty in regards to how
widespread precipitation will be and/or who will see the higher
amounts. This will be highly dependent on the track of the system as
it moves across the Great Lakes and where mesoscale processes aid in
augmenting precipitation totals. Tagging on with the precipitation
chances, depending on the track of the system we could also see
windier conditions as well.
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 622 PM EDT MON JUL 16 2018
Expect VFR conditions through the forecast period.
&&
.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 407 PM EDT MON JUL 16 2018
High pressure gradually building into the region will bring
diminishing winds tonight. By Tuesday, the high pressure will build
across western Lake Superior, so expect the gustier winds to around
20 knots be confined across eastern Lake Superior. Later in the
week, high pressure will move across the region bringing light winds
on Wednesday/Thursday.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
None.
Lake Michigan...
None.
&&
$$
SHORT TERM...JLB
LONG TERM...Ritzman
AVIATION...07
MARINE...JLB
Area Forecast Discussion
National Weather Service Blacksburg VA
733 PM EDT Mon Jul 16 2018
.SYNOPSIS...
An upper level disturbance will track across the region this evening
into tonight. A cold front will pass through the area Tuesday.
High pressure will build in for Wednesday.
&&
.NEAR TERM /THROUGH TUESDAY/...
As of 720 PM EDT Monday...
Not much coverage overall, but several small areas of
showers/thunderstorms, especially along the southern Blue Ridge
and into NE TN close to upper shortwave. Should see more of a
scattering of shower/storms this evening in the west and
isolated in the east if any. Things will subside in the east by
midnight, then more showers/storms are expected ahead of an MCV
by dawn Tuesday in the WV mountains.
Previous discussion...
An upper level disturbance, shortwave aloft will travel east across
the region this afternoon into tonight. Cooling aloft associated
with this feature will create steepening mid level lapse rates this
afternoon. After a lull in convection this morning due to cloud
cover, coverage in showers and thunderstorms will increase this
afternoon into this evening. The primary focus of storms will be
along and west of the Blue Ridge with the best low level convergence
from southerly winds as supported by NAM,GFS and ECMWF. The Namnest,
SPC HRRR3 and HRRR were hinting at slightly better coverage across
the north. With slow moving deeper convection, there is the
potential for localized heavy rainfall. With high PWATs between 1.50
to 2.00 inches and slow moving storms, rain rates may exceeding 3
inches in an hour. Antecedent conditions are dry with stream levels
at or below normal, however, high rates can/will quickly compromise
storm drains and poor drainage areas. WPC Day 1 excessive rainfall
highlights the flood potential with the marginal threat area. An
isolated strong to severe pulse thunderstorm may also be
possible this afternoon. However, with little shear and
organization present, most storms will remained well below
severe criteria.
Overall areal coverage of showers and thunderstorms is expected to
decrease tonight with loss of solar heating, but threat will not
entirely go away due to the soupy airmass, lingering outflow
boundaries, and an approaching cold front from the Ohio Valley, all
of which will provide as a lifting mechanism for nocturnal showers
in the west. Areas of low clouds and fog will develop overnight into
Tuesday morning. It is going to be another mild night with low
temperatures ranging from the mid 60s in the mountains to the lower
70s in the piedmont.
A cold front should reach the western mountains Tuesday morning and
rotate east Tuesday afternoon across area. Convergence from frontal
boundary and a weakly defined lee trough just east of the Blue Ridge
should foster scattered to numerous showers and thunderstorms. The
potential for locally heavy rains will continue Tuesday with high
PWATs. The severe threat will be limited mainly by the instability
and timing of the boundary. The Day 2 convective outlook placed the
greater severe threat to our northeast with marginal to slight
from mason- dixon line north into New England. High temperatures
Tuesday will vary from the mid 70s in the west to around 90
degrees in the east.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY NIGHT/...
As of 210 PM EDT Monday...
A cold front will clear the mountains and foothill counties by the
evening then Southside VA around midnight. Most of the forecast area
will stay rain-free through the rest of the period as dry high
pressure wedges south into the Carolinas. The only exception will be
across the Mountain Empire to the Bluefield WV where the wedge will
erode and an inverted surface trough stretches north from the
Tennessee Valley to the southern Ohio Valley Thursday. Coverage of
convective will be scattered. Shower will fade during the evening.
Models are not quite as dry with the wedge in the lower level as
previous run have been. The theta-E boundary stalls along the 460
corridor Wednesday, then drops to the VA/NC border Wednesday night.
With more moisture in the lower level, we can expect thick stratus
clouds along and east of the Blue Ridge to hang around through the
morning, possibly into the afternoon. Temperatures Wednesday morning
will range in the 60s with the higher values being south of 460. If
clouds burn-off by the early afternoon, temperatures will range from
the upper 70s to lower 80s across the mountains to mid 80s east.
With the theta-E boundary moving south Wednesday night, slightly
cooler temperatures are possible with mid to upper 50s across the
mountains and lower 60s east. The theta-E boundary retreats north on
Thursday but the area will maintain a cool easterly flow. This setup
along with thick low clouds will have uniform temperatures across
the area Thursday, ranging from the upper 70s to lower 80s west of
the Blue Ridge to the mid 80s east.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...
As of 230 PM EDT Monday...
The wedge will hang around again on Friday, but will erode from the
west and southeast. An upper level trough is expected to become a
close low over the Great Lakes on Friday. This low will send short
waves into the Ohio Valley and erode the wedge from the west. Across
the Southeastern states, a tropical disturbance is expected to track
along the wedge boundary, then off the North Carolina coast Friday
night. As this disturbance advances north, it will erode the wedge
from the southeast. By the end of the day Friday, the wedge may be
nestled along the VA foothills and linger into the night. Areas
outside of the wedge Friday could see scattered showers in the
afternoon and evening hours.
On Saturday, the closed low expands into the Deep South and covers
most of the US from the Mississippi Valley eastward. In the
afternoon, there is a negative tilt to the trough in the eastern US
that could bring active weather to the region. A weak cold front
will then slide across the region Saturday night. Sunday and moreso
Monday, could be active days with heating occuring under the cold
pool.
The area will remain under a trough through most of next week as a
strong blocking ridge drifts westward in the Western Atlantic.
Afternoon and evening showers and thunderstorms are likely each day
from this weekend into the following week. Temperatures will run at
or cooler than normal through the period.
&&
.AVIATION /00Z TUESDAY THROUGH SATURDAY/...
As of 723 PM EDT Monday...
Expect showers, maybe thunderstorm in vicinity of most sites
this evening for another hour before activity weakens or
diminishes. Should be mainly VFR with at times MVFR/IFR cigs.
Fog again possible overnight in the mountains, but cloud cover
ahead of front will act to keep it limited. Still going LIFR at
LWB for a small window in the 10-12z time frame. Confidence is
medium on this happening.
A cold front will reach the mountains Tuesday morning and move
east across the region Tuesday afternoon. There is a continued
threat of MVFR/IFR with storms associated with the cold front.
Medium confidence in ceilings, visibilities and winds during the
taf period.
Extended Aviation...
The cold front will continue to move east into Tuesday night with
post frontal drying Wednesday. Return flow will bring moisture
back into the area Thursday and Friday. Scattered showers and
thunderstorms with sub-VFR conditions are expected Saturday and
Sunday.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...None.
NC...None.
WV...None.
&&
$$
SYNOPSIS...KK/PM
NEAR TERM...KK/WP
SHORT TERM...RCS
LONG TERM...RCS
AVIATION...KK/PM/WP
Area Forecast Discussion
National Weather Service Shreveport LA
947 PM CDT Mon Jul 16 2018
.UPDATE...
Latest regional radar mosaic showing scattered convection across
far NE LA and east of the Mississippi River attm with a general
southward motion. The western flank of this activity extends into
the MLU area but the coverage is isolated to widely scattered at
best. Convection earlier that was dropping south of the Red River
across SW AR into NE TX has since dissipated.
For the update this evening, the latest runs of the HRRR and the
00z NAM output not showing much more in the way of convection
overnight except across extreme S AR and NE LA where an outflow
boundary can be seen in our ground cover pattern per the KSHV
WSR-88D. For this reason, have left slight chance pops going for
the remainder of the night across our northern and eastern most
zones.
Taking a look at temps, hourly numbers were quite a bit lower
across our northern zones than this time last night and this was
due to overturned airmass from previous convection. Closer to the
I-20 Corridor, temps were very near those of last night. Did bump
up temps slightly across NE TX, especially near the TYR area
where upper 70s have been common the last couple nights.
Only other change was to the sky grids to account for expanding
cirrus shield that may help to hold temps up as well overnight.
Update out shortly...13.
&&
.PREV DISCUSSION... /issued 515 PM CDT Mon Jul 16 2018/
AVIATION...
The upper level ridge axis has retrograded to our west and
northwest and that has allowed upper level disturbances to ridge
the eastern flank of this ridge axis and interact with moisture
and instability with the end result being scattered convection.
Looking at the latest progs, it appears that the ridge will have
enough influence on our NE TX terminals and the SHV terminal to
leave any mention of convection out of this TAF package through
the next the next 24 hours, though it may be close at the SHV
terminal during the morning hours on Tue.
Concerning the TXK/ELD and MLU terminals, will prevail VCTS
through the next 24 hours with this scattered convection coming
and going over the TAF period. No definitive window in the short
term progs allows for the breaking up this long period of VCTS at
these locations. Also added a TEMPO group this evening for limited
VSBY and -TSRA at the ELD terminal as this terminal appears the
most under the gun to see convection early on.
Winds will be mostly from the south and southwest below 10kts
overnight and through the day Tuesday, except variable in and
around -TSRA at the TXK/ELD and MLU terminal through the TAF
period.
13
&&
.PRELIMINARY POINT TEMPS/POPS...
SHV 79 99 78 99 / 10 10 10 20
MLU 78 95 76 94 / 20 40 30 30
DEQ 74 93 73 95 / 20 30 30 20
TXK 77 97 76 96 / 20 30 20 20
ELD 76 95 75 95 / 20 30 30 30
TYR 79 98 77 100 / 10 10 10 10
GGG 78 98 76 100 / 10 10 10 10
LFK 75 97 75 99 / 10 10 10 10
&&
.SHV WATCHES/WARNINGS/ADVISORIES...
AR...None.
LA...None.
OK...None.
TX...None.
&&
$$
13/13
...Update to aviation forecast discussion...
.SHORT TERM...(This evening through Tuesday)
Issued at 342 PM CDT Mon Jul 16 2018
Forecast area this afternoon remains on the southern periphery of
a surface high translating eastward across the Northern Plains,
associated with the back side of an upper trof extending northward
out of the Great Lakes. Between the weak surface reflection of
the boundary and shear vorticity aloft, showers and thunderstorms
have developed in north central Kansas this afternoon. Wind
profiles in the soundings remain very weak, with the NAM sounding
at Hebron barely breaking 10kts through the first 10kft off the
surface. CAPE values remain summer like, with around 2000j/kg
surface based, and enough dry air in the lowers 5000ft of the
soundings to make collapsing storms pose a heavy rain then wind
threat for today. Better ingredients lie farther northeast, but
lack of a boundary to focus the lift keeps better chances in north
central and central Kansas.
Much of how the forecast plays out for Tuesday will depend on how
nocturnal convection develops to the northwest and propagates
southeast. There is a broad concensus that convection over the
high plains in Wyoming late tonight moves southeastward into
Nebraska overnight, with favorable corfidi vectors to bring that
into our area. However, convection to the south over the
panhandles and into south central and central Kansas may limit the
amount of moisture transport northward by the nocturnal LLJ,
leaving in question how strong the cluster would be before it got
this far southeast. Certainly would anticipate at least remnants
making it this far, which could then in turn aid as a focus for
storms later in the day. As for the line across central Kansas,
storms that develop along the mid level front should also move to
the southeast, and the RAP giving some indication of a complex
over eastern Colorado that may follow that boundary to the
southeast into the morning hours. Will keep a forecast with
slightly higher pops across the southwest early, but then
increasing across the north into the east into the afternoon.
Stronger storms may still occur with any convective complex early,
but once again a day with low shear and high cape will make
strong storms possible into the afternoon. This in turn will also
impact cloud cover and temperatures as well, and will start with
highs around 90 south to middle 80s north. Lows tonight forecast
in the upper 60s to near 70 before better rain chances come in.
.LONG TERM...(Tuesday night through Monday)
Issued at 342 PM CDT Mon Jul 16 2018
Multiple, ill-timed chances for precipitation linger through the
week, with continued summertime temperatures at or slightly above
normal.
A broad, longwave blocking ridge holds through the period over
the southwestern U.S., with the eastern CONUS longwave trough
gradually deepening through the period as multiple shortwaves work
across the Northern Plains. This will promote an active NW flow
over the central United States. On Tuesday evening, one such wave
will be located over Wyoming and aiding in the development of a
convective cluster over the High Plains. The detailed evolution of
this complex is not fully resolved by the various guidance, but
there is a growing concensus that the MCS will build SSE into a
30-40 kt LLJ in western Kansas throughout the night on Tuesday and
into Wednesday morning. The MCS should decay through the morning,
but the uncertainty lies in how the MCS cold pool or cloud shield
drives/hinders convective chances later in the day. These
mesoscale details will likely not be fully resolved until
Wednesday morning, but there is a modest chance that an outflow
boundary lingering in central/eastern Kansas that will serve as
the focus for renewed shower and storm development Wednesday
afternoon.
The H500 trough is also progged to deepen during this time over
South Dakota and help promote synoptic ascent. The kinematic
environment may be initially supportive of semi-discrete cells,
but outflow boundaries are likely to quickly merge and promote
upscale growth into a cluster or line with strong winds being the
main threat. A backdoor trough wrapping around the departing H500
trough may generate another round of convection Thu afternoon in
central SD that could propagate southeastward through Nebraska
into eastern Kansas into Friday morning. There is some discrepancy
amongst the 12Z GFS/EC in the timing of this wave and the
resultant precip with the GFS being the more progressive of the
two. After the passage of this system, the H300 ridge amplifies
and keeps the pattern dry through the weekend. Temperatures during
the period will be near average, though mesoscale cold pool
influences are to be expected with any precip Wed and Thu.
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 637 PM CDT Mon Jul 16 2018
VFR conditions are expected outside of convective activity. Models
suggest that a complex of storms may affect the terminals after
14Z Tuesday and have added VCTS at this time.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...67
LONG TERM...Skow
AVIATION...53
Area Forecast Discussion
National Weather Service Tucson AZ
235 PM MST Mon Jul 16 2018
.SYNOPSIS...Plenty of moisture and instability will remain in
place to support daily showers and thunderstorms through at least
the middle of the week. Some storms will generate strong winds
and heavy rain. Partial drying from the east may lead to reduced
thunderstorm coverage by the weekend, along with hotter
temperatures.
&&
.DISCUSSION...Daytime heating in combination with an inverted trough
approaching the area were aiding in the development of showers and
thunderstorms this afternoon in the mountains. A strengthening
steering flow from the northeast to east in association with the
approaching inverted trough will also help storms to move into the
valleys today. Recent HRRR solutions supported the notion of storms
tracking into lower deserts of Pima and Pinal counties this evening.
Locally heavy rainfall will be the main concern, but the environment
will also support strong thunderstorm winds. Models were in
agreement with tracking the inverted trough through northern Mexico
tonight and Tuesday with less of an influence for tomorrow`s
thunderstorm potential. High pressure aloft will become established
over the Great Basin region around Wednesday before shifting over
the Desert Southwest this coming weekend. This adjustment in the
position of the upper high will result in some warming and drying
aloft by the end of the week. This warmer and drying will eventually
translate to less thunderstorm activity and hotter daytime
temperatures by week`s end.
&&
.AVIATION...Valid through 18/00Z.
Isolated to scattered SHRA/TSRA through late this evening can be
expected. Cloud bases 8k-12k ft AGL with SCT-BKN clouds above 20k.
Winds remain below 12 kts through the period, with stronger gusts
possible around TSRA. Aviation discussion not updated for TAF
amendments.
&&
.FIRE WEATHER...An active weather pattern will continue to produce
showers and thunderstorms, mainly during the afternoon and evening
hours. Toward the middle of the week, a shift begins to take place
bringing in drier air and reducing rain chances. However, isolated
storms could still develop, especially over the higher terrain.
Temperatures also gradually warm through the week. 20-ft winds
remain below 15 mph, although the Upper Gila River Valley will
experience gustier northwesterly winds at times.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...None.
&&
$$
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