Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 08/04/18
Area Forecast Discussion
National Weather Service State College PA
910 PM EDT Fri Aug 3 2018
.SYNOPSIS...
A plume of deep tropical moisture will continue to stream north
across the Commonwealth into early tonight bringing locally
heavy rain. A weak cold front will push east across Pennsylvania
later tonight and early Saturday, sweeping the moisture off the
Mid Atlantic Coast. High pressure building in will bring drier
but still humid weather and increasing sunshine throughout the
upcoming weekend.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
Focus for heavy rain and flooding will be over the southeast
corner of the forecast area overnight. Radar loop at 01Z is
showing and area of heavy rain falling at nose of low level jet
over southeast Pa. PWATS near 2 inches, combined with capes near
1000 j/kg, should support rates of over 1 inch an hour in spots
overnight. Latest HRRR runs support additional rainfall amounts
overnight of 2+ inches in some spots from Harrisburg south and
east.
Elsewhere, based on latest near term model runs and radar
trends, may be able to shave off the western edge of the flash
flood watch late this evening.
High pressure and associated drier air mass will build in from
the Grt Lks late tonight, bringing clearing skies and developing
valley fog to the western counties.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH SUNDAY/...
Low level jet and deepest moisture will have shifted east of the
region Saturday. However, passage of upper trough could support
a few lingering showers, primarily over the southeast counties
during the morning and during peak heating of the afternoon over
the Allegheny Plateau. For most of the region, arrival of high
pressure and lower PWATs will translate to fair and dry
conditions. The return of sunshine should allow temperatures to
recover to the 80s Saturday afternoon. Fair weather Sat night
with overnight lows from near 60 north to 70 south.
&&
.LONG TERM /SUNDAY NIGHT THROUGH FRIDAY/...
The long term period returns with a ridge over the region that
will stifle any precipitation Sunday into Monday. This coupled
with a high over the south will bring warmer temperatures and an
increase of humidity into middle of the week. There is a chance
for POPS Monday afternoon but only slight as there is a lack of
instability. This will cease as a deepening trough approaches
through southern Canada and will trek through the upper Great
lakes and into the region Tuesday and Wednesday. This will bring
the next chance for showers/thunderstorms. An unsettled pattern
looks to be in store through the latter half of next week.
Temperatures will rebound to be around normal through the
weekend and into next week.
&&
.AVIATION /01Z SATURDAY THROUGH WEDNESDAY/...
Rain activity continues to shift east, and is focusing more
across the middle and lower Susquehanna Valley at 00z.
Highly variable conditions are expected across the east, with
VFR/MVFR conditions punctuated with IFR in heavier rain. Thunder
has still been very limited across the area, but will continue
to include in KMDT and KLNS TAFs in response to HRRR continuing
to insist on blossoming convection between 00z and 08z.
As rain tapers off across the west, expect widespread fog
development, with IFR/LIFR conditions becoming prevalent across
much of the region.
For Saturday, expecting widespread morning fog, and some
lingering rain in the east, with improvements to VFR in all
areas by later morning into early afternoon.
.Outlook...
Sat...Morning fog/low clouds central and west in the AM.
Lingering rain and IFR restrictions in the east. Becoming VFR.
Sun...Patchy AM fog possible, otherwise VFR.
Mon...Mainly VFR, with isolated PM TSRA impacts possible
West.
Tue...Mainly VFR, with scattered PM TSRA impacts possible.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
Flash Flood Watch until 8 AM EDT Saturday for PAZ028-036-042-
046-049>053-056>059-063>066.
Flash Flood Watch until 10 PM EDT this evening for PAZ012-018-
019-024>027-033>035-037-041-045.
&&
$$
SYNOPSIS...Watson
NEAR TERM...Fitzgerald
SHORT TERM...Watson/Fitzgerald
LONG TERM...Lambert/Ceru
AVIATION...Jung
Area Forecast Discussion
National Weather Service Dodge City KS
540 PM CDT Fri Aug 3 2018
...Updated aviation discussion...
.SHORT TERM...(This evening through Saturday)
Issued at 157 PM CDT Fri Aug 3 2018
There is increasing confidence in a rain and thunderstorm episode
developing this evening, lingering through the overnight. An upper
trough will be moving east across the CO/KS line from around
00-03 UTC, and will be the focus for upper forcing for vertical
motion in a decent area of CAPE and shear. The initial storms may
bring risk of severe wind gusts through the evening hours, but
move into weaker instability eastward. Current runs of the HRRR
linger showers and storms across our central Kansas counties
through perhaps 8 am before a more subsident regime takes over for
the balance of Saturday. Tonight will mark the beginning of a
series of much warmer overnight, with lows only falling to around
the 70 degree mark.
.LONG TERM...(Saturday night through Friday)
Issued at 157 PM CDT Fri Aug 3 2018
The extended period continues to show an increasing mean daily
temperature trend through Monday before a cold front around
Monday night provides a respite back to below normal highs for
early August in sw Kansas. NAM at this time is showing increasing
positive vorticity advection Sunday night into the central and
northern High Plains region, resulting in MCS activity north of
our area. Additional rain and thunderstorm activity should be
ongoing along the synoptic front into early Monday, as the NAM
shows, and supported somewhat by the ECMWF. Model blends have
significantly cut highs for Monday into the 80s.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 540 PM CDT Fri Aug 3 2018
Scattered showers and thunderstorms developing over eastern
Colorado late this afternoon are expected to continue to move
across southwest and central Kansas this evening into tonight.
Any potentially severe weather, mainly severe wind gusts, should
be confined to far western Kansas before sunset. Will continue the
previous forecast trend of carrying a period of SHRA with VCTS for
a few hours at each terminal.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 70 94 70 97 / 50 20 0 0
GCK 67 94 68 98 / 80 10 0 0
EHA 65 95 69 97 / 70 0 0 0
LBL 65 96 69 99 / 60 10 0 0
HYS 70 91 70 96 / 80 20 0 0
P28 73 93 71 97 / 30 20 0 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Russell
LONG TERM...Russell
AVIATION...Gerard
Area Forecast Discussion
National Weather Service Glasgow MT
800 PM MDT Fri Aug 3 2018
.DISCUSSION...
Evening Update...
Main change to the forecast was to increase pops and winds over
the southern zones through the evening. Although there is very
little lightning with the showers moving across Garfield and
Prairie counties this evening, with dewpoint depressions of over
40 degrees has allowed strong to severe wind gusts under the
leading edge of the precipitation. Miles City has recorded wind
gusts of over 60 mph and there has been some minor damage in
Prairie County associated with these winds. The HRRR seemed to
handle the strong winds the best, so blended with that for the
next few hours to handle this. The SREF seemed to handle
precipitation the best, so used that to update the pops. These
showers and strong winds should move out of the area by late this
evening. Otherwise, made minimal changes to the temps and
humidity values.
Previous Discussion...
With an upper-level weather disturbance from the northern Rockies,
gusty winds and spotty thunderstorms have begun to spill over the
continental divide this afternoon. This slightly more active
weather pattern has allowed for a bit more atmospheric mixing
today.
We expect the scattered rain showers and isolated thunderstorms to
spread through eastern Montana through the rest of this afternoon
and evening. Much of it will likely be virga showers, but the
stronger storms, mainly south of the Missouri River, could result
in a little rainfall accumulation here and there.
Tonight, the re-enforcing cooler air behind the cold front will
allow for decent humidity recoveries over the next several days.
As this weather pattern continues with slightly more moist
conditions up and over the northern Rockies, there will remain
slight chances of some scattered rain showers and isolated
thunderstorms off and on through the remainder of this weekend.
The best chances seems to be late Sunday through early Monday.
Beginning Monday and persisting through most of next week, a
strong ridge of high pressure will re-establish itself over the
western states, the Rocky Mountains and the near adjacent high
plains regions for a return to hot and dry conditions.
BMickelson
&&
.AVIATION...
Flight Category: Expecting mainly VFR conditions.
Discussion: A weather pattern that is slightly more unsettled
from the Pacific Northwest, will bring periods of hit and miss
showers and thunderstorms to the region over the next few days.
Vicinity showers will be possible this afternoon and evening,
especially for KGDV, but confidence is not high enough to include
it in the prevailing TAF lines. Amendments may be needed.
Winds: From the west and northwest around 15 to 20 kts with a few
higher gusts. Gusts under the leading edge of the showers may
bring gusts of 40 to 60 mph. These should move out of the area by
around 06Z tonight.
BMickelson / Hickford
&&
.GLASGOW WATCHES/WARNINGS/ADVISORIES...
Red Flag Warning until midnight MDT tonight for
MTZ120-122-134>137.
&&
$$
weather.gov/glasgow
Area Forecast Discussion
National Weather Service Wilmington NC
821 PM EDT Fri Aug 3 2018
.SYNOPSIS...
Showers and a few thunderstorms will continue into the weekend,
but a building upper ridge will begin to lessen rain coverage
overall. Typical summer conditions will prevail early next
week, but a developing upper trough to the west, may bring a
return of abnormally wet weather.
&&
.NEAR TERM /THROUGH SATURDAY/...
As of 820 PM Friday...IR imagery shows tops warming quickly across
the southwest portion of the forecast area. Expect the area of light
to moderate rainfall (debris from earlier thunderstorms) to continue
to weaken as it moves toward the northeast. Other areas of
dissipating rainfall will affect portions of Darlington and Marlboro
counties over the next couple hours. Otherwise, the last several
runs of the HRRR have been consistent with showers and thunderstorms
redeveloping along coastal areas during the early morning hours. As
a result, plan to lower POPs far inland overnight, while increase
them along the coast during the early morning. If trends suggest
more widespread convection by morning then will need to issue a
Flash Flood Watch for a few coastal counties. No other significant
changes are expected with the next update.
Previous discussion... Convection exiting the Pee Dee region early
this afternoon remains strong, with rainfall rates of 1-1.25 inches
per hour. Further east, individual embedded cells have been
producing on the order of 0.25-0.5 inch per hour. For the remainder
of the afternoon, convective activity should remain somewhat limited
by the stabilizing affect of debris clouds from rainfall earlier
today. This is apparent in visible satellite imagery, which shows
delayed cumulus development beneath a cirrus canopy. However a swath
of very high precipitable water will remain across the eastern
Carolinas through Saturday. Think the GFS MOS guidance may be
relying heavily on that swath of moisture to produce the 50-60 PoPs
for tonight, and I plan to cut those back to 30-40, as hi-res models
indicate overnight activity will remain scattered. Saturday
convection should follow a more typical diurnal cycle, as the 500 mb
ridge shifts overhead from the Atlantic.
&&
.SHORT TERM /SATURDAY NIGHT THROUGH SUNDAY NIGHT/...
As of 330 PM Friday...A shift in the mid-level pattern occurs
this weekend as the persistent ridge of high pressure offshore
retrogrades westward. Guidance suggests this high will shift so
far west that the local area will see mid-level winds shift all
the way around to the north on the eastern periphery of the high
by Sunday night. This will create lowered convective chances
during the short term: initially due to weakened lapse rates,
and later in the period thanks to some drier air aloft. Despite
a pattern that more closely resembles typical August in the
Carolinas, aftn thunderstorms will be possible Sunday, with
higher POP likely nearer the coast where PWAT will remain over
2" and lapse rates will be slightly steeper. Additionally, a
weak shortwave trough may drop along the eastern edge of the
ridge late providing subtle impetus for lift. POP will be in the
CHC range Sunday, and although some shower activity may linger
each night, most of it should wane with loss of heating so only
SCHC POP will continue, with POP Saturday night higher than
Sunday night.
Highs Sunday will likely reach the low 90s most places, which
combined with high dewpoint air will drive heat index values over
100 for the first time in a while. Mins both nights will remain
muggy, 72-75 Saturday night, and a degree or so warmer Sunday
night.
&&
.LONG TERM /MONDAY THROUGH THURSDAY/...
As of 330 PM Friday...The agreement seen in GFS/ECMWF long
range H5 depictions, suggest the abnormally wet pattern of late,
may very well return to the region by the middle of next week.
This after a weekend and early week respite, from soaking,
standing water, as an upper ridge briefly holds over the area.
Unsettling is the solution of a stagnant pattern from mid week
into next weekend, implying multiple days of potentially
excessive rain. Temperatures this period near climatology in the
daytime, and above normal Min-T readings.
&&
.AVIATION /00Z SATURDAY THROUGH WEDNESDAY/...
As of 00Z...An area of debris cloudiness and light to moderate rain
will likely pass between KFLO and KMYR/KCRE through 02Z as it
weakens. Showers and a few tstms will likely develop again during the
early morning hours primarily impacting the coastal terminals
through the morning. KFLO and KLBT may see more convection during
Saturday afternoon. Otherwise, some confidence IFR CIGs developing
at KFLO and KLBT overnight along with MVFR VSBYs.
Extended Outlook...MVFR/IFR from scattered to numerous SHRA/TSRA
each afternoon and evening across all sites through the extended.
&&
.MARINE...
NEAR TERM /THROUGH SATURDAY/...
As of 820 PM Friday...A weak pressure gradient prevails across the
coastal waters this evening with winds generally around 10 knots or
less. Seas still remain in the 3-4 ft range from the old southerly
fetch. Southerly winds will likely pick up a notch overnight as high
pressure gains more influence. Otherwise, scattered showers and a
few thunderstorms are expected to develop overnight and move north
across the waters.
Previous discussion...High pressure will remain centered off
the coast through Saturday, though it will elongate and result
in a slightly weakening pressure gradient across area waters.
Southerly winds should become south-southwest Saturday, but only
on the order of 10-15 knots. This will also allow seas to fall
off to around 3 feet. Widespread showers and thunderstorms
affecting the waters this afternoon will diminish from south to
north over the next several hours, with only isolated activity
expected to linger overnight and into Saturday.
SHORT TERM /SATURDAY NIGHT THROUGH SUNDAY NIGHT/...
As of 330 PM Friday...High pressure offshore will ridge back
towards the west through the weekend. This causes the gradient
to relax and winds to veer from S/SE early, to W/SW late, with
speeds 10-15 kts Saturday night, and around 10 kts otherwise.
These light winds combined with a low amplitude ground swell
will cause seas to drop from around 3 ft early in the period, to
more uniformly 2 ft Sunday and Sunday night.
LONG TERM /MONDAY THROUGH WEDNESDAY/...
As of 330 PM Friday...A typical summer pattern this period, in
that we can expect S-SW winds of 10-15 kt, with a few higher
gusts inshore in the afternoon, or near isolated showers and
TSTMS. Rain coverage will be less in this period that what we
have seen recently. Seas of 1.5-3 ft will be a mix of wind-waves
from the SW and longer period swell waves from the SE. Radar
updates are encouraged, especially later Tuesday into Wednesday.
&&
.ILM WATCHES/WARNINGS/ADVISORIES...
SC...None.
NC...None.
MARINE...None.
&&
$$
NEAR TERM...SRP
SHORT TERM...JDW
LONG TERM...MJC
AVIATION...SRP
AREA FORECAST DISCUSSION
National Weather Service Jackson KY
1101 PM EDT Fri Aug 3 2018
.UPDATE...
Issued at 1101 PM EDT FRI AUG 3 2018
Convection has remained confined to north of the Ohio River thus
far, but could still see a remnant shower/storm make it into
northern portions of eastern Kentucky tonight as a shortwave
trough and potential outflow boundary kick through northeastern
Kentucky. Otherwise, expect valley fog to take hold through the
night into Saturday morning.
UPDATE Issued at 803 PM EDT FRI AUG 3 2018
Mostly clear skies remain in place west of the local Interstate 75
corridor with a few patches of low to mid clouds farther east
across the higher terrain, stemming from earlier convection in
Tennessee. A few cells continue to thrive just southeast of
Louisville along with trailing development moving into southern
Indiana and Ohio associated with an approaching shortwave trough.
May see a shower or storm graze the Bluegrass region later this
evening into tonight, but the brunt of this should stay north of a
Flemingsburg to Sandy Hook line.
Clearing skies and light winds will promote valley fog tonight
into Saturday morning, although may see some dampening of this as
lingering cloud cover propagates through northeastern Kentucky.
&&
.SHORT TERM...(This evening through Saturday night)
Issued at 347 PM EDT FRI AUG 3 2018
We remain under the influence of surface high pressure of the
Atlantic coast this afternoon. The better shower and thunderstorm
activity has remains south and east of eastern Kentucky, as the
more favorable lift associated with the upper level jet progresses
eastward. We have seen a few isolated showers in the southeast
today but these have been limited to that part of the CWA.
We do see some support from the mid and upper levels track across
the Ohio Valley later this evening into tonight. The HRRR shows a
few cells developing tonight into Saturday morning and some of
the other CAMs as well, but overall the coverage looks limited.
The synoptic driven models also showed differing stories with the
NAM being the most robust with activity later tonight. Given the
uncertainty did add isolated showers and thunderstorms mainly
north of I-64. Otherwise, expect some mainly river valley fog
overnight into Saturday morning. There is some question to the
extent of the coverage given the potential for some cloud cover
related to the upper level wave. Even so seems like a good shot
for those river valleys to see at least some fog production.
The struggle likely comes in relation to the building heights as
an upper level ridge retrogrades westward this weekend. Given this
and the lack of coverage seen in the mesoscale models opted to
keep it dry for Saturday into Saturday night. Again, chances of
river valley fog exist Saturday night. The more noticeable change
will be the increase in temperatures back to slightly above
normal for this time of year through the weekend.
.LONG TERM...(Sunday through Friday)
Issued at 452 PM EDT FRI AUG 3 2018
An unsettled period is in store. An upper level ridge over the
southeast CONUS will be weakening as the period starts. A
seasonably moist low level air mass will already be in place. A
shortwave trough over the mid Mississippi Valley at the start of
the period will move east and should approach the JKL forecast
area late Monday, further weakening the ridge and increasing our
POP. This wave will dampen as it arrives, but a deepening of a
larger scale eastern CONUS trough will also be underway, providing
increasing support for precip as midweek approaches. It will also
support a cold front to move southeast, reaching the Ohio Valley
late Tuesday or Tuesday night. Warm and humid air will continue to
advect into our area ahead of the front. The GFS is more
pronounced with the eastern CONUS upper level trough late in the
week when compared to the ECMWF, which allows the GFS to have a
quicker, cleaner passage of the surface cold front than the ECMWF.
A model compromise yields our highest POP in the north on Tuesday
and in the south on Wednesday, with all areas decreasing later in
the week. Exactly how quickly the precip tapers off will depend
on the strength and progress of the upper trough and how
effectively drier low level air can move in, which will need to be
settled as the time draws closer.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
ISSUED AT 803 PM EDT FRI AUG 3 2018
CB/TSRA remains northwest of a KBWG to KFFT to KCMH line this
evening. May see a shower or storm approach KFGX to KSYM later
this evening into tonight, but confidence in impacts at KSYM
remains low enough to preclude mention at this time. Cloud cover
from this convection may somewhat hinder fog development across
portions of northeast Kentucky, but still banking on a good deal
of river valley fog by early Saturday morning. Given drier air
mixing to the surface this past afternoon at most TAF sites, have
left fog mention (MVFR/IFR visibilities) in the forecast for only
KSJS from 8-12Z as greater near-surface moisture resides. VFR
conditions will return by mid Saturday morning as winds remain
near or below 5 knots from 180 to 270 degrees.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...GUSEMAN
SHORT TERM...DJ
LONG TERM...HAL
AVIATION...GUSEMAN
Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
649 PM CDT Fri Aug 3 2018
.SHORT TERM...
231 PM CDT
Tonight through Saturday...
Relatively quiet weather is expected heading into the weekend,
with breezy and much warmer conditions on tap for Saturday.
Upper ridge builds into the region tonight, downstream from an
upper level trough over southwestern Canada and the Pacific
Northwest, and a short wave emerging from the central Rockies.
Resulting surface pressure falls from the Northern Plains into the
Canadian prairie provinces will induce southwesterly return flow
into the Upper Midwest and western Lakes into the weekend.
In the near term, seasonably warm air was in place across the
forecast area this afternoon, with light winds within an area of
weak surface high pressure allowing the inland push of a lake
breeze across the Chicago metro area. While dry weather is
expected to prevail over the area, an isolated late afternoon
shower or thunderstorm can`t be entirely ruled out across the far
southern tier of WFO LOT cwa counties, where low level moisture
has pooled along a weak warm frontal boundary. Thermodynamic
profiles are actually more impressive this afternoon than they
were yesterday in our south, with RAP based mesoanalysis
indicating 2000-2500 J/kg of MLCAPE and 30 kts of effective deep
layer bulk shear. Boundary layer flow is quite weak however, with
surface winds less than 5 kts in many obs, so convergence is very
weak. Probability/coverage are both likely pretty low for any
storms to develop there and have maintained just some "silent
pops" of around 10 percent there this afternoon. Farther
northwest, a few decaying showers have worked into southwestern
Wisconsin from convection over Minnesota. Expectation is that
these will continue to decay and should not pose a significant
precipitation threat into northern IL. May see a period of broken
cirrus into northern IL this evening however, as upper level winds
stream this convective anvil debris southeastward.
Southwesterly low level flow ramps up the heat into the area
Saturday, with warm advection enhanced by the central Rockies
short wave lifting across the Upper Mississippi Valley. Guidance
depicts 850 mb temps approaching +20C during the day, which will
likely support low-mid 90 degree high temps during the afternoon.
Relatively dry profile aloft across the forecast area should
result in mixing dew point temps down however, resulting in lower
humidity levels than the heat we had in early July. Dew points in
the 60s to near 70 (lower in the city, and much lower than the
75-80 dews seen in early July), will yield heat indices fairly
close to the air temps, peaking in the mid-upper 90s. Southwest
winds will become breezy during the day, with gusts near 20 mph
likely by mid-late afternoon. This will suppress any significant
lake cooling, with 90 degree warmth expected right up to the Lake
Michigan shore.
Ratzer
&&
.LONG TERM...
220 PM CDT
Saturday night through Friday...
Saturday night and Sunday: More pronounced upper-ridging will begin
to shift farther east of the CWA. Weak capping, minimal deep-layer
forcing, and a general lack of sufficient low-level moisture should
keep the area dry during the time. Sunday will be another warm day
on gusty SW winds, with highs in the low 90s and heat index values
reaching the mid to upper 90s. There is a decent chance temps may
top out in the mid 90s for much of the area at the expense of
increased mixing and lower dew points, but resultant heat index
values would remain in the mid to upper 90s.
Sunday night through Tuesday: A cold front will slowly shift south
across the western Great Lakes during this time in response to the
amplification of a broad trough across the Upper MS Valley. Several
rounds of thunderstorms are expected to track along this front, with
the main focus across the CWA falling into the Monday afternoon
through Monday night time frame. However, from late Sunday night
through Monday morning, some thunderstorm activity across IA and WI
may reach the northwest half the CWA.
The potential for severe storms appears a bit lower in today`s
guidance compared to yesterday. However, deep-layer shear to 40
knots with MLCAPE values around 1500 j/kg will support strong to
severe storms late Monday afternoon through the evening. There is
also a threat for locally heavy rain as deep-layer flow parallel to
the frontal boundary will support the potential for training
thunderstorms.
Tuesday through Friday: The front should clear the far SE CWA by mid-
morning Tuesday, resulting in a dry with seasonable temps. A broad
trough will settle across the area Wednesday before the trough
strengthens over the Great Lakes region Thursday. Guidance has
backed off on higher precip potential Thursday night as sufficiently
deep moisture now remains south of the CWA. Otherwise, a few
diurnally forced showers and maybe thunderstorms will be possible
each afternoon with general cyclonic upper-level flow over the area.
Drier low-level will limit coverage of the activity.
Kluber
&&
.AVIATION...
For the 00Z TAFs...
Lake breeze effects are being felt in the near term but winds will
turn southeasterly overnight and around to southwesterly by
tomorrow. Due to a stronger background pressure gradient tomorrow
a lake breeze passage appears less likely than today, so these
southwest winds would persist through the day tomorrow with gusts
into the upper teens likely developing in the afternoon. Dry and VFR
conditions are expected through the forecast period.
Lenning
&&
.MARINE...
220 PM CDT
Through Sunday night, Lake Michigan will remain between expansive
high pressure over the eastern seaboard and an elongated trough over
the northern and central Great Plains. Resulting south winds to 25
knots are expected Saturday through Sunday night, with some gusts
to 30 knots across the north half of the lake Saturday night into
Sunday morning. The trough will then slowly shift south across
Lake Michigan Monday into Tuesday morning, with NW winds to 20
knots behind the front. Multiple rounds of thunderstorms, some
strong, are possible during this time. Generally W to SW winds
under 20 knots are expected Thursday into Friday as the area
remains between low pressure over Hudson Bay and broad high
pressure over the southern states.
Kluber
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...None.
IN...None.
LM...None.
&&
$$
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Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
804 PM CDT Fri Aug 3 2018
.SHORT TERM...(This evening through Saturday)
Issued at 345 PM CDT Fri Aug 3 2018
The forecast concern near term is extent and severity of
convection overnight and again into Saturday.
Persistent low level WAA over the northeast CWA will continue the
threat of thunder into the evening. This may gradually slide
farther east overnight. Meanwhile, water vapor imagery showing a
couple of weak mid level short waves. One over eastern North
Dakota this afternoon is forecast to move east over the western
CWA this evening. 12z CAMS were indicating developing into west
central MN this evening. Still looks good that some development
will occur into that region as the short wave moves in. Still
pretty unstable with MLCAPES to 3000 J/kg and effective shear
around 40kts into west central MN at this time. We may yet see
convection congeal into some linear complex in the evening per
early morning CAMS. Strong winds and perhaps some large hail
would be the main severe weather threats, with west central MN
outlooked with SLight Risk front SPC. Pretty capped at least
surface wise with mid level cap moving into southwest MN. HRRR
trends have been pretty inconclusive as far as overall
development. Will have to continua to monitor. Overall, still
looks like a likely PoP is warranted to the west with chances
moving east overnight.
Development farther east will be modulated by any significant
complex that would develop farther east. Still low level jet is
expected to move east and may be enough with the upper wave to
generate convection into the east into Saturday morning. Will
need at least some likely PoPs over the east into at least the
morning. Expect activity to remain much of the morning with
clouds limiting significant destabilization. Still the next mid
level short wave moves into the region and could still see at
least a slight risk of severe weather over west central MN later
in the afternoon/evening once again.
.LONG TERM...(Saturday night through Friday)
Issued at 345 PM CDT Fri Aug 3 2018
The thunder threat will continue into Monday as the main upper
trough and surface front move through later Sunday night into
Monday. Then drier weather will move in for early next week with
overall warming trend expected by later in the week. The
deterministic models diverge some on timing of upper ridging
building into the cwa with the GFS a bit faster with its warming.
We could see a small chance of convection as this warming aloft
arrives with the GFS and blended guidance bringing the slight
chance around the Wednesday time frame. We will follow that for
now.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 804 PM CDT Fri Aug 3 2018
A complex of thunderstorms continues to move east across central
MN, and is expected to impact STC/RWF/MSP. Winds may gust out of
the west up to 30-40 kts and visibility may drop to MVFR in the
heaviest rain as these storms move through. Overnight, additional scattered
showers and thunderstorms are expected to develop and linger into
the morning, winds will pick out of the south with gusts up to
20-25 kts developing. ANother round of showers and thunderstorms
may develop tomorrow afternoon but this threat is conditional on
how precipitation overnight & tomorrow morning evolves.
KMSP...Expecting thunderstorms to aproach the area beginning
around 830 PM, and impacting the terminal around 9-11 PM. Winds
may gust out of the west up to 30-35 kts. After these storms exit,
expecting another round of scattered tunderstorms around sunrise
& lasting through the morning.
/OUTLOOK FOR KMSP/
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
&&
$$
SHORT TERM...DWE
LONG TERM...DWE
AVIATION...ETA
Area Forecast Discussion
National Weather Service Pueblo CO
815 PM MDT Fri Aug 3 2018
.UPDATE...
Issued at 815 PM MDT Fri Aug 3 2018
Updated pops based on current radar and high res model trends.
I did keep slight pops across the Central Mts and into the higher
terrain of the Pikes Peak region through midnight, with current
echoes across the Northern Mts. Models and radar trends do
diminish and weaken these storms as the continue to move east
southeast. However, will need to continue to monitor these storms
through the rest of the evening with the possibility of adding
pops back to portions northern portions of El Paso County and
northern portions of the southeast plains, if these storms hold
together.
&&
.SHORT TERM...(This evening through Saturday)
Issued at 206 PM MDT Fri Aug 3 2018
A disturbance moving across the state today will continue bringing
showers and thunderstorms to the area, with the activity expected to
decrease and end from west to east this evening. By 06Z the HRRR
and NAM show most, if not all precip being done, but there could be
some lingering precip near the KS and OK borders. The GFS shows
some lingering precip over the central mtns thru about midnight.
With the disturbance exiting the area tonight, clouds will also
decrease.
The main concern with storms today will be the potential for locally
heavy rain that could impact recent area burn scars, presenting a
flash flooding risk. There is also the potential for one or two
severe storms over the southeast plains, especially the far
southeast plains, with hail around 1" in diameter and wind gusts
around 60 mph being the main threats.
On Saturday, the upper ridge builds over the area again, but there
will still be enough moisture over the area for isolated to
scattered showers and tstms in the afternoon and evening hours,
mostly over the mtns and high valleys. Temps on Sat should be a
little warmer than today.
.LONG TERM...(Saturday night through Friday)
Issued at 206 PM MDT Fri Aug 3 2018
Synoptic Overview...Weak upper level high pressure will be centered
over Arizona/New Mexico to start the long term period, leading to
westerly flow over Colorado Sunday through Monday with fairly
potent disturbances advancing through the flow just to the north.
Large ridge then builds over the western US, leading to increasing
northwest flow over Colorado Tuesday into Wednesday, to northerly
flow Thursday into Friday. Subtropical high over the southeast US
helps maintain GoM moisture tap into southern Colorado through the
first half of next week. Increasing northerly flow by end of the
week should start to scour moisture out of state. Flash flooding
remains a threat over burn scars each day given above normal
moisture. Models remain in good agreement on the evolution of the
mid-upper level pattern through the long term.
Sunday...Atmospheric moisture across Colorado will continue to
rebound during the day Sunday (TPW rising over 1") after having
dropped behind the Friday evening storm system. While relatively
undisturbed westerly flow remains over southern Colorado, a
shortwave will progress through the northern Rockies.
Afternoon/early evening thunderstorms are forecast to develop over
the mountains and eastern plains, with storms over the plains being
aided by energy associated with the northern shortwave and surface
convergence related to a lee trough. CAPE and especially shear will
be on the weaker side, so don`t expect much in the way of severe
storms. Temperatures will rise into the upper 90s to around 100
across the plains, and upper 80s to around 90 in Colorado Springs
and the high valleys.
Monday through Tuesday...The Sunday shortwave and convection sends a
cold front down the eastern Colorado plains late Sunday through
Monday. Behind the front on Monday, surface winds become upslope
easterly, driving higher surface dew points across the plains into
the eastern mountains. TPW values will also rise to around 1.5"
across the southeast quadrant of the state. Scattered to widespread
convection will develop across the eastern mountains and spread onto
the plains during the afternoon, aided by the upslope flow and
another mid-level shortwave. Given abundant moisture, flash flooding
will be of particular concern this day especially on burn scars and
across urban areas. High surface dew points will drive up CAPE
values, and surface easterlies below mid-level westerlies will
increase deep layer shear. Therefore, there will be heightened
severe potential across the plains and eastern mountains as well.
However, abundant storm coverage may help to limit the severe
threat, particularly hail, later in the day. Tuesday is looking
similarly active as surface easterlies and heightened moisture
content remain in place and mid-level flow starts to become
northwesterly. Temperatures will become progressively cooler each
day, with highs across the plains in the mid 90s on Mon to low 90s
on Tue, and low to mid 80s in Colorado Springs and the high valleys.
Wednesday through Friday...As northwest to northerly flow increases
over the eastern Rockies, atmospheric moisture will progressively
decrease each day. Given still adequate moisture and weak
disturbances in the flow, isolated to scattered afternoon/early
evening thunderstorms are forecast, primarily over the eastern
mountains, with coverage/chances decreasing progressively each day.
While a few severe storms will still be possible Wednesday,
weakening shear and only marginal instability will limit severe
chances thereafter. Temperatures will remain near climatology
through the end of the week.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 206 PM MDT Fri Aug 3 2018
Showers and thunderstorms will be possible at KCOS, KALS and KPUB
early this evening hours. Storms will have the potential for heavy
rain and gusty winds, and some of the stronger storms could also
produce small hail. Storms are expected to move out of the terminal
forecast locations before midnight. Sat, showers and thunderstorms
are expected to develop over the mtns, and if they move into the
vicinity of the terminal forecast sites, it looks like that should
occur after 22Z.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...MW
SHORT TERM...28
LONG TERM...LINE
AVIATION...28
Area Forecast Discussion
National Weather Service Blacksburg VA
900 PM EDT Fri Aug 3 2018
.SYNOPSIS...
A very moist airmass over the Mid-Atlantic region will finally
begin to shift east, bringing a decrease in the coverage of
showers and storms for the weekend as weak high pressure builds
over the area.
&&
.NEAR TERM /THROUGH SATURDAY/...
As of 857 PM EDT Friday...
Layered PWAT Composite Satellite imagery shows the deeper
moisture that has plagued our area for the past several days is
finally beginning to shift east, but low to mid level moisture
remains in place. This was reflected in the RNK evening
sounding with PWAT values falling to 1.32", from 1.7" this
morning.
Isolated showers continue to dot our region, mainly in the south
and east along a weak sfc trof. With our area remaining near the
RR quad of an upper level jet axis to our north and west, would
not be surprised to see spotty showers linger into the early
overnight hours, and have kept small pops well into the
overnight hours to account for this. Coverage should gradually
diminish, as a upper level wave in northern WV and associated
vort axis extending south into our area lift northward tonight.
With light winds, clearing skies and abundant low level
moisture,expect stratus and some areas of fog to develop with
strong signals from the SREF model as well the Rapid Refresh
Ensemble System for this scenario. Only minor adjustments to
made to the forecast lows.
High pressure will keep most of the area dry Saturday, however
with afternoon heating and available moisture, scattered
thunderstorms are possible.
&&
.SHORT TERM /SATURDAY NIGHT THROUGH MONDAY NIGHT/...
As of 315 PM EDT Friday...
Lingering piece of the residual upper trof will finally lift
out Saturday night allowing for a period of ridging aloft to
take shape into early next week. This will make for drier days
for Sunday into Monday with any convection mainly orographically
driven over southwest sections Sunday and across the west Monday
with a gradual return of deeper moisture. However appears much
of the period will be dominated by high pressure offshore and
subsequent subsidence as seen via dry air aloft off latest
forecast soundings and instability. Thus running with no more
than diurnally driven chance pops Sunday/Monday with overall
mainly sunny days and mostly clear overnights. Will be much
warmer given heating of somewhat drier air under weak southwest
flow that will bump 850 temps to above +20 deg/C Sunday into
Monday.
&&
.LONG TERM /TUESDAY THROUGH FRIDAY/...
As of 300 PM EDT Friday...
Return to another unsettled/wet period appears in store during
the extended outlook as brief ridging across the southeast
states breaks down early in the period with a return to upper
troffiness by midweek. This will allow for moisture to quickly
return ahead of a series of cold fronts that will dive
southeast toward the region before likely stalling near or just
east of the region by Friday. Main aspect of this will be with
increasing coverage of daily showers and thunderstorms, espcly
Wednesday into Thursday, when 500 mb heights will be lower and
perhaps coupled with pieces of shortwave energy per latest GFS.
Thus plan to have pops bumping up to higher chances by Tuesday
afternoon followed by high chance to likelys Wednesday/Thursday
and at least chance coverage on Day7. Will see temperatures
return to more summery levels as midweek 850 mb warming combines
with periods of westerly flow to push highs to around 90 east,
and well into the 80s west through midweek. This before seeing
some slight late week cooling as the combination of
fronts/moisture act to temper highs back into the 70s and 80s.
&&
.AVIATION /01Z SATURDAY THROUGH WEDNESDAY/...
As of 730 PM EDT Friday...
lingering showers impacting KLYH and KDAN with some MVFR cigs
will come to an end by 02Z (10 PM EDT), which will temporarily
bring VFR conditions early this evening. However,expect MVFR
Cigs and Vsbys to re-develop late tonight at all TAF sites due
to areas of fog and low stratus forming from light winds and a
very moist ground. Confidence on the coverage of clouds and
extent of fog is low to moderate, but high that this hazard will
impact some TAF sites.
VFR conditions and good flying weather expected Saturday, after
the stratus and fog erode by mid-morning. Light winds are
expected through the period.
Extended...
Moist airmass will slowly diminish during the weekend with a
return to a more summerlike pattern as upper ridging builds in
from the Atlantic limiting storms to mainly the
afternoon/evening variety. Until then should expect periods of
sub-VFR conditions in storms as well as at night/early morning
at most sites.
Confidence is moderate to high, both temporally and spatially
throughout the extended period.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...None.
NC...None.
WV...None.
&&
$$
SYNOPSIS...JH/RCS
NEAR TERM...PH/RCS
SHORT TERM...JH
LONG TERM...JH
AVIATION...PH/RCS