Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 10/02/17
Area Forecast Discussion
National Weather Service Bismarck ND
926 PM CDT Sun Oct 1 2017
.UPDATE...
Issued at 919 PM CDT Sun Oct 1 2017
Thunderstorms have ended across northern North Dakota and most of
the showers also. Still expecting a surge of moisture and showers
moving up into the southeast late tonight. Several of the CAM
models are trending this shower area east of the James River
Valley. Trimmed POPs east late tonight from likely to chance.
UPDATE Issued at 704 PM CDT Sun Oct 1 2017
The precipitation trends are following the CAM model forecasts
pretty well so feel confident the majority of showers and
thunderstorms will be out of the southeast within one to two hours
and the rest of the north during the evening. The threat of severe
weather has greatly diminished so have removed the mention of
severe from the forecast.
UPDATE Issued at 458 PM CDT Sun Oct 1 2017
This update will focus on POPs along the line of thunderstorms
moving through south central North Dakota. Expect this line to
continue moving northeast with time over the next 3 hours then
exit the region. Upped POPs and QPF.
&&
.SHORT TERM...(This evening through Monday)
Issued at 213 PM CDT Sun Oct 1 2017
Forecast highlights in the short term period will continue to be
showers and thunderstorm chances now through early this evening.
Still expect a window for strong to severe storms 19-01Z today
over my central and east, more so my south central and southeast.
Currently, large trough of low pressure remains over the western
CONUS with strong southwest flow aloft over the Northern Plains.
Strong embedded S/WV impulses rotating around the trough and
lifting northeast across the region resulting in showers across
eastern MT/western ND and across the upper Mississippi. Surface
trough over the central Dakotas will be the focus for possible
strong to severe storms this afternoon as we destabilize.
Clearing has been occurring the past few hours along the trough
axis and has led to CU development over south central ND. ESRL
HRRR has consistently focused convective initialization in this
area between 19-20Z.
SPC earlier moved the marginal risk farther west for severe
thunderstorm potential, just east of Minot and Bismarck for the
remainder of this afternoon into early this evening. This
conditional severe threat seems plausible and supported by the
latest CAM suites. 1000-1500 J/KG of MLCAPE and effective deep
layer shear around 30 kts, will combine with strong sfc forcing
and support aloft for a few organized updrafts. Main threats will
be large hail (quarter to golf ball size) and winds up to 70 mph
for the stronger storms. Given low cigs and 0-1KM shear a low end
tornado threat will also exist.
Precipitation will decrease from southwest to northeast early to
mid evening as drier air advects into our area. Another strong
embedded wave will bring a decent chance for showers to the James
River Valley overnight.
.LONG TERM...(Monday night through Sunday)
Issued at 213 PM CDT Sun Oct 1 2017
Cooler temperatures this coming week, and perhaps a rain snow mix
west Tuesday morning highlight the extended forecast.
Upper level low develops Monday night over eastern MT and remains
over the state through mid week before lifting northeast. This
feature will keep some precipitation chances over our area through
Tuesday. Temperatures in the mid 30s Tuesday morning across the
west may support some potential for a possible light rain and
snow mix, though will need to see what temperatures aloft do.
Right now a mix would be more favored to our west. Highs
generally in the 50s are favored through mid-week. Afterwards
models show a wide spread of solutions.
&&
.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 704 PM CDT Sun Oct 1 2017
00Z TAFs will be challenging this evening as the trends are
quickly changing. Showers and thunderstorms scattered from KMOT
to KJMS ending by 01-02Z. Showers with a mix of MVFR/IFR KDIK-
KMOT-KBIS becoming VFR after 03-06Z. After 06z VFR expected at
all taf locations.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...WAA
SHORT TERM...NH
LONG TERM...NH
AVIATION...WAA
Area Forecast Discussion
National Weather Service Hastings NE
641 PM CDT Sun Oct 1 2017
.SHORT TERM...(This evening through Monday Night)
Issued at 225 PM CDT Sun Oct 1 2017
An active weather pattern is expected across the local area
through the short term periods. With clearing to our west this
afternoon...instability has been building ahead of an approaching
cold front. Currently this front extends from near O`Neill
Nebraska southwest into eastern Colorado. Can already see some
cumulus starting to develop along the boundary...although nothing
has yet to really take off. That said...with plenty of
instability...effective shear values of 35 to 40 kts...and
forcing from the front...think that it is only a matter of time
before strong convection begins to initiate.
With the aforementioned parameters...have no trouble imagining
that organized convection will develop...with the potential for
large hail...strong thunderstorm wind gusts...as well as an
isolated tornado or two. Will continue to monitor...but think that
this convection will initiate to our west around 4 PM or 5
PM...making it to our western fringes by early evening...and
spreading east across the forecast area during the mid evening
through overnight hours. Short term model guidance is in fair
agreement with this...with both the HRRR/RAP developing a line of
thunderstorms and taking it east later this evening. With a
developing LLJ on the warm side of this boundary...expect
convection to persist through much of the overnight hours...but
with the best potential for severe storms coming primarily before
midnight.
With the cold front expected to stall across the local area
tomorrow...expect a fairly good temperature gradient to develop by
afternoon...with highs in the lower 60s forecast for our
north...and mid 80s forecast across out southeast. This front
should also become a focal point for convection during the late
afternoon and evening hours...with another chance for strong or
marginally severe thunderstorms late in the day tomorrow. While
severe potential does not look as great tomorrow...expect at least
the potential for marginally severe hail and 60 mph winds gusts
with the strongest storms through the evening hours.
.LONG TERM...(Tuesday through Sunday) Issued at 225 PM CDT Sun
Oct 1 2017
Continued unsettled weather is expected through much of the
extended periods as a cold front meanders across the local area.
This should keep temperatures near or slightly below
normal...with multiple chances for showers and a few thunderstorms
across parts of the local area...although severe weather appears
unlikely at this time. The main frontal boundary will eventually
shift southeast of the local area by next weekend...with dry
conditions and a return to above normal temperatures returning
next Saturday afternoon and Sunday.
&&
.AVIATION...(For the 00Z KGRI/KEAR TAFS through 00Z Monday)
Issued at 635 PM CDT Sun Oct 1 2017
Scattered severe thunderstorms across western KS and NE will
continue eastward into the evening, eventually impacting both TAF
sites, but also gradually decreasing in intensity.
The HRRR model is handling the ongoing convection very well, so I
have leaned on it heavily for this TAF issuance. The HRRR fills
the ongoing storms into a well defined line that moves
southeastward. This makes sense given the increasing low-level
jet. As such I have included a brief period of prevailing TS at
both sites.
Some LLWS is also expected before the boundary passes through the
area tonight. Behind this boundary, we could see cloud ceilings
drop into the MVFR category into Monday morning.
&&
.GID WATCHES/WARNINGS/ADVISORIES...
NE...None.
KS...None.
&&
$$
SHORT TERM...Rossi
LONG TERM...Rossi
AVIATION...Mangels
Area Forecast Discussion
National Weather Service North Platte NE
957 PM CDT Sun Oct 1 2017
.UPDATE...
Issued at 957 PM CDT Sun Oct 1 2017
Dropped Severe Thunderstorm Watch at 10 PM CDT and removed severe
wording from wx grids.
UPDATE Issued at 859 PM CDT Sun Oct 1 2017
Updated to drop tornado watch.
UPDATE Issued at 641 PM CDT Sun Oct 1 2017
Updated forecast to add north central zones in severe thunderstorm
watch.
&&
.SHORT TERM...(This evening through Monday)
Issued at 327 PM CDT Sun Oct 1 2017
Strong forcing now moving into western Wyoming and Colorado per
water vapor imagery. This will quickly overspread western and
southwest Nebraska this evening, and expect rapid development of
thunderstorms along a pacific cold front that extends from west of
O`Neill to near Ogallala. This boundary will remain nearly
stationary this evening, and we will have to watch areas of
southwest Nebraska closely near the front for possible isolated
tornado development. Backed near surface flow will increase this
evening, and if a storm can remain discrete near the boundary,
parameters are decent for isolated tornado development. Recent runs
of the HRRR model suggests that many updrafts could limit the
potential for storms to remain discrete. This would pose more of a
wind and hail risk and less of a tornado threat. Front should clear
the area by midnight, with only a few lingering rain showers behind
the front.
Surface low pressure will deepen across eastern Colorado Monday,
which will stall the cold front just to our southeast during the
morning. The front will actually drift back northward into the
southeast portion of the area during the afternoon. Mid level
instability will begin to increase by late afternoon as warm air
advection and southerly low level jet increase. This will set the s
stage for a round of elevated strong thunderstorm activity Monday
night. As far as rainfall during the day Monday, expecting it to be
scattered at best, but cannot rule out with persistent mid level
warm air advection and isentropic lift through the day.
.LONG TERM...(Monday night through Sunday)
Issued at 327 PM CDT Sun Oct 1 2017
Both the NAM and GFS indicate the h850mb front will lift back north
toward Ncntl Neb Monday night. 50-60kt h850-700mb winds produce
strong moisture advection and the NAM indicates h800mb CAPE around
3000J/KG with strong shear aloft. The environment is generally post
frontal suggesting a high potential for elevated thunderstorms
capable of hail, perhaps large at times. The forecast carries a
definite POP for showers and thunderstorms. K-indices are expected
to rise into the upper 30s to lower 40s Celsius.
A similar situation develops Wednesday with a warm front lifting
back north in response to an approaching upper level wave. The
forcing at the lower levels is weaker suggesting a less widespread
rain event affecting areas south of highway 2.
The last potential rain event develops Thursday night and Friday as
the last of the upper level energy across the Wrn U.S. lifts east
through the Plains. The models have a large range of tracks for the
upper low and there has been a whole lot of wobbling day to day with
each model forecast.
Blended model data plus bias correction was the basis for the
temperature forecast. The coolest weather is expected Wednesday; the
result of 1030mb Canadian high pressure ridging southward through
the high plains. Highs in the 50s are expected area-wide Wednesday.
Otherwise highs in the 60s are expected until Saturday. Warmer
weather returns Saturday and Sunday.
&&
.AVIATION...(For the 18Z TAFS through 18Z Monday afternoon)
Issued at 104 PM CDT Sun Oct 1 2017
A stormy late afternoon and evening is expected across western and
north central Nebraska. Expect thunderstorms to develop this
afternoon across the western high plains, and then move east
across the area this evening. Temporary MVFR conditions are likely
as the storms cross the area. Winds will be locally gusty to 40
kts as the storms pass as well. VFR and light winds are expected
by Monday morning all areas.
&&
.LBF WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
UPDATE...Snively
SHORT TERM...Taylor
LONG TERM...CDC
AVIATION...Taylor
Area Forecast Discussion
National Weather Service Miami FL
750 PM EDT Sun Oct 1 2017
.AVIATION...
As easterly flow becomes deeper and more pronounced, shower activity
will gradually increase as it moves offshore from Atlantic waters.
VCSH is warranted after about 2z along the east coast and by mid-
morning for Naples. TEMPO or prevailing groups may be needed for
parts of Monday, but at this point its too early to pinpoint timing.
Wind will be E around 10 KT tonight then increase to 15 to 20 KT
during the day Monday.
&&
.UPDATE...
Most of the afternoon convection has ended at this time with a
few brief streamer showers moving inland from the Atlantic. The
latest short ranged models suggest these streamer showers will
continue to move inland along the east coast metro areas through
tonight. Tonight low temperatures will range between the mid to
upper 70s. Easterly flow will continue tomorrow and increase in
the afternoon hours as the ridge gradually builds over the region.
Chance of scattered showers and thunderstorms will develop in the
afternoon. Current forecast remains on track.
&&
.PREV DISCUSSION... /issued 316 PM EDT Sun Oct 1 2017/
DISCUSSION...Latest surface observations and sat imagery show a
more east to se flow already in place across the region with a few
showers starting to develop over Palm Beach and Broward County
and over Central FL. This easterly flow is advecting some moisture
into the region, which will enhance more convection in the
afternoon hours. Model guidance suggests this activity will
persist this afternoon with the best chances remaining towards the
ne and the interior counties. This activity will produce moderate
to heavy rainfall with the main threat of brief periods of heavy
rain that could cause minor flooding. Max temperatures will be
around the 90s and cool down into the upper 70s tonight.
Convection should diminish inland and transition over the Atlantic
waters into the evening hrs.
Next week, broad upper level ridge building over the northeast plains
will help push weak boundary over the panhandle south along the FL
peninsula. Surface gradient will also strengthen increasing to
breezy to windy conditions through the week with the potential for
numerous showers and storms. This feature will help to maintain deep
tropical moisture over the region through midweek, which will
continue the wet pattern with scattered to numerous showers. Models
are hinting on another weak tropical wave moving into the region by
the end of the week bringing even more deeper moisture into the
area. This will continue the potential for more numerous showers and
storms through the end of the week. Temperature are forecast to drop
slightly along the east coast metro region down into the mid 80s, a
couple degrees cooler than normal for this time of year.
MARINE...Weak boundary over the panhandle of FL will enhance num
showers and storms deteriorating marine conditions through much
of the week. Ridge builds over the region and strengthen easterly
winds across South Florida. This will result in a long period of
windy conditions and high seas over the Atlantic waters. Small
Craft Advisory are in effect for the Atlantic waters starting
tonight and continuing through mid week. Monitoring the Gulf
waters as conditions may also be near SCA as well, but at this
time left SCEC conditions into Monday.
AVIATION...Easterly flow prevails through the period 10-15kts
at all sites with gusts 18-20kts will possible along the east
coast this afternoon. Winds diminish 8-10kts after 02Z, though
KFLL may remain around 12kts. Winds increase after 14Z tomorrow
12-15kts with gusts to 20kts through day. SHRA may impact KFXE-
KPBI this afternoon, while other east coast sites look to remain
dry until this evening. SHRA expected VCNTY KAPF through 00Z.
SHRA expected to continue moving into the east coast through the
upcoming TAF cycle. TSRA coverage looks limited, so no mention
in forecast. May see MVFR cigs/vsbys with heaviest activity.
BEACH FORECAST...The rest of today moderate risk of rip currents
continues over the Atlantic waters and transition to high risk
this week as easterly winds increase across the region. The
elevated risk will likely persist through most of the week. A
weak boundary over the region will maintain abundant moisture
over South Florida providing periods of numerous showers and
thunderstorms through the week.
PREV DISCUSSION... /issued 128 PM EDT Sun Oct 1 2017/
AVIATION...Easterly flow prevails through the period 10-15kts
at all sites with gusts 18-20kts will possible along the east
coast this afternoon. Winds diminish 8-10kts after 02Z, though
KFLL may remain around 12kts. Winds increase after 14Z tomorrow
12-15kts with gusts to 20kts through day. SHRA may impact KFXE-
KPBI this afternoon, while other east coast sites look to remain
dry until this evening. SHRA expected VCNTY KAPF through 00Z. SHRA
expected to continue moving into the east coast through the
upcoming TAF cycle. TSRA coverage looks limited, so no mention in
forecast. May see MVFR cigs/vsbys with heaviest activity.
PREV DISCUSSION... /issued 949 AM EDT Sun Oct 1 2017/
UPDATE...Low pressure trough still extends across the eastern
Gulf of Mexico into North/Central Florida this morning, along with
a broad upper level low and associated weak surface low off the
east coast of Florida. These features will dampen out today as
surface high pressure builds in from the NE and upper level
ridging moves in from the west.
Morning sounding came in with PWATs around 1.6" and warm midlevels
around -5.5C. With winds becoming more easterly as the high
builds in, we will advect a little better moisture, especially in
the low levels, back into the region. With daytime heating, expect
scattered to locally numerous showers to move from east to west
across the area through the afternoon. Best chances will continue
to focus around Lake Okeechobee and along the Gulf coast later in
the afternoon. Can`t rule out a few storms, but overall expect
mostly showers. Breezy conditions are expected along the east
coast into this afternoon.
PREV DISCUSSION... /issued 428 AM EDT Sun Oct 1 2017/
DISCUSSION...
Latest IR satellite imagery shows a break in the cloud cover over
south Florida with convection off of the northern Florida Atlantic
coast. The 00Z MFL sounding indicated a thin layer of CAPE above
850 mb, with southerly winds 10 to 15 KT spanning from the
surface up to the mid levels. NWS radar has been rather quiet this
morning, with no distinct features to enhance shower activity.
East southeast flow will advect in a moderate amount of moisture
today with more widely scattered showers anticipated. Short range
models, including the HRRR and WRF show limited activity
developing this afternoon, with a couple embedded heavier storms.
The main threat will again be brief heavy rain, and isolated
cloud to ground lightning strikes. Maximum temperatures will
approach the low 90s across the western peninsula and upper 80s
for the east coast metro region, typical for this time of year.
Through mid week: By Monday, models begin to build a dominant
high pressure cell over the eastern CONUS and mid Atlantic waters,
tightening surface pressure gradients, and increasing easterly
flow over South Florida. A stationary boundary is forecast to
remain stagnant across central Florida. This feature will help to
maintain deep tropical moisture over the region through midweek,
which will continue the wet pattern with scattered to numerous
showers. Forecast GFS PWAT values should fluctuate from 1.75" to
2.25". Both the GFS and ECMWF show an easterly wave moving
westward over the peninsula from Wednesday into Thursday. This
would act to further enhance lift and moisture, likely producing
more widespread precipitation. Also, expect an extended period of
breezy easterly winds, esepcailly over the coastal waters and
along the east coast beaches. Maximum temperature are forecast to
drop slightly along the east coast metro region down into the mid
80s, a couple degrees cooler than normal for this time of year.
MARINE...A tropical disturbance will continue to meander across
North Florida and the northeast Gulf of Mexico enhancing coverage
of showers and storms today and Monday. High pressure building
over the eastern CONUS will produce east winds 20-30 KT over the
Atlantic waters this evening through mid week. Waves will increase
to 6 to 11 feet through this period for the Atlantic, creating
dangerous conditions for small craft.
&&
.PRELIMINARY POINT TEMPS/POPS...
West Palm Beach 81 86 83 85 / 50 70 30 60
Fort Lauderdale 81 87 81 85 / 50 70 30 60
Miami 80 86 79 85 / 50 60 30 60
Naples 77 89 75 89 / 20 60 10 50
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...None.
AM...Small Craft Advisory from 11 PM this evening to 4 AM EDT
Thursday for AMZ650-651-670-671.
GM...None.
&&
UPDATE...67/MT
AVIATION...23/SK
Area Forecast Discussion
National Weather Service Melbourne FL
937 PM EDT Sun Oct 1 2017
.UPDATE...
...Flooding Impacts Expected to Continue across Brevard County
Overnight...
Convergent shower bands that brought extremely heavy rainfall to
areas from Floridana Beach and Melbourne Beach to Palm Bay and
West Melbourne has shifted northward gradually into late evening
bringing heavy rainfall to central Brevard. A mesonet observation
site in Floridana Beach has reported 10.68 inches of rain since
midnight and still raining. Another mesonet site in Palm Bay has
seen 9.13 inches since midnight with a West Melbourne site
reporting 7.57 inches today. Flash Flood Warning has been reissued
and covers portions of central and southern Brevard counties
through 1130 pm. HRRR suggest strongest convection will shift
south overnight while other guidance suggests Brevard and Indian
River may remain the focus for Atlantic showers bands through the
overnight hours. Radar trends show another primary rain band from
the Cape eastward developing across the Atlantic that should
eventually shift gradually south overnight but will continue
threat for locally heavy flooding rainfall across central/srn
Brevard counties to Indian River county later tonight. Have made
adjustments upward to POPs/QPF in areas that will be focus for
additional onshore moving showers through the night. Flood Warnings
will likely be extended for portions of Brevard county into the
overnight hours.
&&
.AVIATION...
Heavy showers moving onshore from the Atlantic will continue
overnight with highest concentration of showers/isolated storms
from KTIX-KVRB corridor into late tonight. MVFR CIGs and IFR VSBYs
associated with convection. Additional showers will affect KDAB
vcnty and KFPR-KSUA with activity diminishing as it moves inland
toward KSFB-KMCO terminals. Some gradually drying across north FL
into the afternoon should shift most shower chances south of
KISM-KTIX line by afternoon.
&&
.MARINE...
Easterly winds increasing to around 20 knots will allow seas to
build to 5-7 ft nearshore and up to 6-8 ft well offshore late
tonight. No significant changes expected with late evening marine
update. Small Craft will be in effect for all waters past 10 pm.
&&
.PRELIMINARY POINT TEMPS/POPS...
DAB 75 84 76 84 / 70 30 30 30
MCO 73 86 72 88 / 50 40 30 40
MLB 77 84 79 85 / 90 50 40 50
VRB 78 84 79 83 / 60 60 40 50
LEE 73 85 71 88 / 40 30 20 30
SFB 73 86 72 86 / 50 30 30 40
ORL 73 86 73 88 / 50 30 30 40
FPR 79 84 80 83 / 60 60 40 50
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...None.
AM...Small Craft Advisory until 4 PM EDT Thursday for Flagler Beach
to Volusia-Brevard County Line 0-20 nm-Flagler Beach to
Volusia-Brevard County Line 20-60 nm-Volusia-Brevard County
Line to Sebastian Inlet 20-60 nm.
Small Craft Advisory until 4 PM EDT Thursday for Sebastian Inlet
to Jupiter Inlet 0-20 nm-Sebastian Inlet to Jupiter Inlet
20-60 nm-Volusia-Brevard County Line to Sebastian Inlet 0-
20 nm.
&&
$$
Volkmer/Weitlich/Smith
Area Forecast Discussion
National Weather Service Pueblo CO
353 PM MDT Sun Oct 1 2017
.SHORT TERM...(This evening through Monday)
Issued at 354 PM MDT Sun Oct 1 2017
...Moderate snow accumulations possible for the central mountains...
Upper level trof across the northern U.S. Rockies will continue to
carve southward across UT/NV through Monday. Shortwaves ejecting
out ahead of this system will bring rounds of precipitation to the
central mountains with one wave moving through late this afternoon
through this evening, and a second round expected on Monday. Lapse
rates will remain steep in model soundings providing a convective
element to snowfall and have seen some briefly heavy snowfall in web
cams through the day across Fremont pass, though roads have remained
generally wet. With snow levels dropping tonight to around 9-9.5
kft, snow may have a better time sticking to road surfaces this
evening. Models then suggest a lull in the action by morning before
another round moves in Monday afternoon. Snowfall totals are coming
up to around 4-8 inches through Monday evening...with most falling
north of Cottonwood Pass. With snow levels looking lower on Monday
given CAA , this may result in some minor impacts to travel over the
higher mountain passes like Fremont in the afternoon. Thus have put
up a winter weather advisory for the higher peaks of the Sawatch and
Mosquito ranges. All in all, looks like totals will fall on the
lower end of the advisory spectrum.
Elsewhere, dry and windy will be the main concern. Fortunately with
wet fuels, critical fire weather conditions do not look to be of
much concern. Still watching for the potential for an isolated
severe to near severe storm along the eastern border...particularly
Baca county. Latest HRRR run is developing thunderstorms across the
far eastern counties where SPC Meso analysis is showing around 1000-
1500 j/kg of mixed layer cape and 40-50 kts of deep layer shear.
While odds for a severe storm are better to the east in KS, just
can`t rule it out entirely across far eastern CO so will carry some
isolated pops out that way through early evening.
Tonight a cold front will drop through the southeast plains. Cooler
airmass then retreats slowly back northward on Monday as strong
southwesterly winds spread back across the region. How far
northward is the challenge and will have greatest impacts on
temperatures. Latest 18z NAM lifts front back to the highway 50
corridor...while GFS is farther north with the front along the
Palmer Divide. Overall went a little cooler in grids north of
highway 50. Otherwise...plains looks largely dry again
tomorrow...but will need to watch the far eastern border where the
front lies up as there could be some higher cape out that way. -KT
.LONG TERM...(Monday night through Sunday)
Issued at 354 PM MDT Sun Oct 1 2017
Main longer term meteorological issues continue to be
temperatures, pops and gusty winds at times.
Initially, upper storm system is expected to provide accumulating
snow over portions of the Central Mountains into Monday evening,
therefore will allow recently issued Winter Weather Advisory to
continue until 9 PM MDT Monday for these locations.
Otherwise, latest longer term forecast model soundings, computer
simulations and PV/precipitable water analysis suggest that the
forecast district will be under southwesterly to zonal upper flow
from Monday night into Thursday night.
Models then diverge on their solutions from Friday into next
weekend with the 01/12Z GFS solution depicting that basically dry
zonal to northwesterly flow will prevail over the forecast
district from later Friday into next weekend as closed upper low
quickly moves east across North Dakota by Friday night. The
01/12Z ECMWF solution indicates a stronger upper system traversing
Colorado from Friday into Friday night before system moves east of
the CWA Saturday.
In addition, north-northeasterly surface surges are anticipated
from Monday night into Tuesday and then again from later
Wednesday night into Thursday and these surges when combined with
occasional upper disturbances will be capable of generating
isolated to scattered pops, especially during the later Tuesday
into Friday time-frame with driest conditions anticipated from
Saturday afternoon into next Sunday.
At this time, it appears that the highest potential for stronger
gradient winds during the longer term should be realized from
Monday night into Wednesday morning.
Overall, generally above seasonal early October minimum temperatures
are expected to continue over the majority of the forecast
district during the longer term, while maximum temperatures are
still projected to run within a category or so of climatological
averages(although much warmer temperatures may be noted by next
weekend if the GFS solution verifies...time will tell.)
&&
.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 354 PM MDT Sun Oct 1 2017
Gusty southwest winds with speeds of 20-30 kts will gradually
decrease this evening...though KALS may see southerly winds around
10-15 kts through the night. This should keep fog from reforming
across the San Luis Valley tonight. Meanwhile...a cold front will
drop through the plains through this evening bringing a northerly
wind shift at KCOS and KPUB. Some MVFR stratus will be possible
towards 12z-16z at both terminals as winds shift around from the east
to southeast. Any stratus that forms should erode by 17z as
southwesterly winds spread back into the region. Should see gusts
around 30 kts at KALS again tomorrow afternoon...with KPUB and KCOS
staying southeast to easterly behind the front with gusts in the 10-
20 kt range at times. -KT
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory until 9 PM MDT Monday for COZ058-060.
&&
$$
Area Forecast Discussion
National Weather Service Tampa Bay Ruskin FL
815 PM EDT Sun Oct 1 2017
.UPDATE...
Most of the area saw scattered showers and an isolated
storm today. The radar has quietened down quite a bit
with only a few stray showers over the coastal waters.
Latest HRRR model guidance is showing mostly dry
conditions overnight. Will make some slight tweaks
to the POPs to show diminishing rain chances through
the night. All other parameters look good for now.
Will send out updates zone shortly.
&&
.AVIATION...
All terminals are currently shower free and will
remain VFR through the period. A stray shower
will still be possible over the next few hours,
so will keep VCSH at all terminals. Winds will
remain out of the east overnight at 10 knots
or less. A slight uptick in wind speeds can
be expected tomorrow afternoon where gusts in
the 15-20 knot range will be possible. No other
aviation impacts expected.
&&
.MARINE...
Winds and seas will continue to increase from
the east through the overnight period as the
trough across the waters weakens and shifts
off to the west, as a strong high pressure
system builds into the region. The increasing
pressure gradient across the waters will allow
for a SCA to be raised across the offshore
waters and northern near shore for tonight.
This will likely need to be expanded for the
Monday and beyond period as the strong ridge
remains in place across the week.
&&
.Preliminary Point Temps/PoPs...
TPA 74 87 73 87 / 20 30 10 20
FMY 75 88 74 87 / 20 50 20 40
GIF 73 84 72 85 / 30 40 10 30
SRQ 74 89 73 87 / 20 40 10 30
BKV 75 86 71 87 / 20 30 10 20
SPG 76 85 74 87 / 20 40 10 30
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...None.
Gulf waters...Small Craft Advisory until 11 AM EDT Monday for Coastal
waters from Tarpon Springs to Suwannee River FL out
20 NM-Waters from Bonita Beach to Englewood FL out 20
to 60 NM-Waters from Englewood to Tarpon Springs FL
out 20 to 60 NM-Waters from Tarpon Springs to
Suwannee River FL out 20 to 60 NM.
&&
$$
UPDATE/AVIATION/MARINE...74/Wynn
UPPER AIR...63/Jillson
DECISION SUPPORT...11/McKaughan
...Update to aviation forecast discussion...
.SHORT TERM...(This evening through Monday)
Issued at 309 PM CDT Sun Oct 1 2017
A broad upper level trough was located across the central Rockies
and will remain stationary as a shorter wave-length trough along the
OR and northern CA coast digs southeast into the base of the broad
upper level trough across the four corners region by Monday
afternoon.
Later this afternoon and evening surface based thunderstorms will
develop near a triple point across southwest NE, then back build
along a surface dryline into western KS. Some of these storms may be
severe as MLCAPES will reach 1500-2500 J/KG. The higher grid
resolution models show a line of scattered thunderstorms developing
across west central KS through the evening hours, then lifting
northeast across north central KS during the early morning hours of
Monday. The HRRR and WRF models show this line of storms weakening
and becoming more isolated as they move east and northeast across
north central KS, then across northeast KS. I kept the better
chances for showers and perhaps a few elevated thunderstorms across
the northwest counties Tonight. A few showers may reach the
northeast counties during the morning hours of Monday. Southerly
winds of 10 to 20 MPH will help keep overnight lows mild with mid to
upper 60s.
Monday, as the west-central conus trough amplifies the cold front
will begin moving north and northwest across eastern NE into
northwest KS. The surface dryline will retreat back west to the CO
and KS border. After the elevated showers have ended during the
morning hours across northeast KS, skies should become partly cloudy
within the warm sector across the CWA. Surface based storms will
develop along the surface front and dryline across west central and
southwest KS during the late afternoon hours. Once again the surface
pressure gradient will continue to be tight across central and south
central KS due to a deepening lee surface low across southeast CO.
Most areas will see southerly winds at 15 to 25 MPH with gusts to 35
to 40 MPH. The southwest counties may flirt with wind advisory
criteria with sustained winds reaching 25 to 30 MPH and gusts around
40 to 45 MPH. If the the mid level clouds dissipate and mixing is a
bit deeper than current forecasts, the next shift may want to
consider the issuance of a wind advisory for portions of north
central KS, but at this time it looks a bit too marginal. Highs will
reach the mid 80s with some areas getting into the upper 80s.
.LONG TERM...(Monday night through Sunday)
Issued at 309 PM CDT Sun Oct 1 2017
Monday night, an amplified positively tilted trough is seen over the
northwestern and north central US with a large ridge over the East.
At the surface, a front located in western Kansas approaches central
Kansas bringing in some PoPs to north central Kansas during the
overnight hours. Mixed boundary layer winds will also persist
overnight as this front moves east keeping wind gusts through the
overnight hours especially near central Kansas. Tuesday, this front
slowly moves into the CWA through the afternoon but soundings
indicate a weak cap which would limit the severe potential,
especially considering only about 30 knots of shear and ML CAPE near
1000 J/kg. Showers and storms are expected to develop Tuesday with
the best chances for storms across the area Tuesday night into
Wednesday morning. Models hang up this front across the area
through most of the work week bringing chances for multiple rounds
of precipitation across the area. PWATS increase through Wednesday
when values from 1.5 to over 2 inches, almost double what is normal
for the beginning of October. These values are primarily located
over east central Kansas where there is the potential for multiple
rounds of heavy rain which may lead to the flooding. This will need
to be continued to be monitored as more details are worked out
within the models. Still some discrepancy in the models for the
weekend as the upper low exits the central US, but overall
precipitation chances should be on the decrease Saturday night and
Sunday.
A temperature gradient exists on Tuesday with north central Kansas
temperatures in the low 70s and low 80s seen for the rest of the
area before the front makes its way through. From here, seasonable
temperatures and cloudy skies persist through the work week. Skies
will start to clear Saturday, with temperatures remaining in the 70s
for the weekend.
&&
.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 604 PM CDT Sun Oct 1 2017
Added LLWS back into the forecast as lowest parts of the boundary
layer appear to decouple enough to warrant its inclusion around
1200ft agl. Atmosphere mixes out quickly again Monday morning and
is once again breezy from the south.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Gargan
LONG TERM...Heller
AVIATION...67