Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 10/03/16
Area Forecast Discussion
National Weather Service State College PA
1153 PM EDT Sun Oct 2 2016
.SYNOPSIS...
An upper low will drift east across the southern peninsula of
Ontario today...keeping a deep-moist southerly flow over the
region. A ridge of high pressure will build east into Pennsylvania
behind this system Monday, and will likely remain over the area
through the middle, and perhaps even the end of the work week
bringing mainly dry and slightly milder conditions across Central
Pennsylvania.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
Upper level low over SW Ontario. System likely to rotate more
clouds into the area later tonight and early Monday.
Still some showers as of 10 PM, especially across the east.
Thus looking at some showers for a few more hours.
Potential for fog, if widespread clearing takes place, and winds
die off. Still not sure on how dense it will get, concern based
on rather high dewpoints.
Been listening to 10 PM TPC call.
Earlier discussion below.
Been watching showers and isolated thunderstorms on the radar
since I came in at 3 PM. Isolated thunder across the north.
Starting to see stronger returns now west of Harrisburg.
Adjusted pops, weather, and clouds some in the grids for this
evening and some time periods overnight.
As the upper low begins to kick out to the east, the influence of
at least one shortwave can be seen with an area of scattered
showers affecting about the western half of the CWA. The RAP meso
anal shows some modest instability with mid level lapse rates in
excess of 6C/km over the NWRN 1/3 portion of the region and a few
hundred Joules of Cape indicated area-wide. Visible shots are
showing some breaks in the overcast so it`s still possible to see
a taller tower cause some thunder and lightning.
Partial clearing can be expected tonight as the showers move east
and dissipate. Clouds will hang in longest over the north but
overall a drying trend will develop as the upper low kicks out to
the north and a westerly flow sets in.
Lows tonight will vary from near 50 over the high terrain of the
north and west to the mid 50s in the SE.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH 6 PM MONDAY/...
Adjusted cloud cover early on during the day on Monday.
Earlier discussion below.
Weak high pressure will build slowly down from the north Monday.
However cyclonic flow and cold air aloft should set up a fair
amount of self-destruct sunshine, especially over the northern
half of the forecast area. While a shower cannot be ruled out, I
used the more optimistic model blended pops that show little more
than an isolated shower early.
Highs will range from the mid 60s north to lower 70s over the
south.
&&
.LONG TERM /MONDAY NIGHT THROUGH SUNDAY/...
Improving weather expected early in the week as upper ridging
builds northward over the region in the wake of departing upper
troffing that has controlled the weather for the last several
days. Abundant sunshine not expected however, as surface high
pushing the cooler air our way slides off the New England coast
midweek, and creates an easterly low level flow once again with a
long fetch of moisture aimed at southern PA. How extensive the
cloud coverage will be and if it will be sufficient to generate
drizzle of even rain is still a question. If part this will depend
on the northward influence of Hurricane Matthew.
The 00Z GFS brings a potent Matthew across the Western Bahamas
then has it paralleling the SE U.S. and Carolina coast late in the
week...before projecting it to get captured by a deepening upper
trough and accelerating north into Long Island next Sat/Sat night.
GEFS has roughly the same track, but as expected becomes more
diffuse through time with the location and intensity of the
storm`s center just off the East Coast.
The 30/12z operational ECMWF parked the storm over or just to the
north of the Bahamas for a prolonged period during the middle to
latter part of the upcoming week, which was a low confidence
solution.
&&
.AVIATION /04Z MONDAY THROUGH FRIDAY/...
A moist upsloping flow will likely result in low cigs along the
spine of the Appalachians from KBFD south to KJST overnight,
while clearing skies and a calm wind will promote areas of fog
across the eastern part of the state. A blend of latest SREF, HRRR
and downscaled NAM support likely IFR/LIFR conditions for the
balance of the night at most Central Pa airfields. Exception may
be KUNV and KAOO, where enough of a breeze could keep sig vis
reductions at bay.
Diurnal heating/mixing within deepening boundary layer will cause
low cigs and fog to lift by late morning. All guidance pointing
toward widespread VFR conds and light wind for Monday afternoon.
Outlook...
Tue-Fri...AM valley fog possible.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SYNOPSIS...La Corte
NEAR TERM...La Corte/Martin
SHORT TERM...Lambert/Martin
LONG TERM...Lambert/Gartner
AVIATION...Fitzgerald
Area Forecast Discussion
National Weather Service Cheyenne WY
927 PM MDT Sun Oct 2 2016
.UPDATE...
Issued at 923 PM MDT Sun Oct 2 2016
We are sending out a quick update to upgrade the high wind watch
to a high wind warning. We are also concerned that the Arlington
zone may hit as well due to those strong winds aloft (60kts) moving
through during the afternoon.
UPDATE Issued at 800 PM MDT Sun Oct 2 2016
We are sending out a quick update to remove the majority of the
precipitation chances this evening. Still may see a little more
coverage overnight, but latest radar loop looks to be pretty
vacant of showers over the area. We are still concerned about the
high wind potential tomorrow afternoon across some areas west of
the Laramie Range. However, there is some potential for mid level
clouds developing in the mid afternoon which may limit full mixing
potential. We are currently collaboration with neighboring offices
on whether or not we should upgrade.
&&
.SHORT TERM...(Tonight through Tuesday night)
Issued at 200 PM MDT Sun Oct 2 2016
Tonight...Isolated showers and thunderstorms continue to develop
west of Interstate 25 and expect this trend to continue with showers
and thunderstorms increasing in areal coverage this evening as
diffluent flow aloft and instability continue to increase. After
midnight, best upward vertical motion will lie from Lusk to Chadron.
Boundary layer progs suggest areas of late night fog and stratus
forming from Chadron to Sidney.
Monday...Potent trough aloft moves from northeast Nevada in the
morning to eastern Montana in the afternoon with a strong Pacific
cold front progged to move to the east across our southeast Wyoming
zones. With the strength of the cold air advection and pressure
rises behind the cold front, along with strong winds aloft, expect
strong winds to develop in the post cold frontal airmass across
Carbon county and over the I-80 Summit and Bordeaux. Confidence
still not high enough to upgrade the high wind watch to a warning,
so will leave this for our overnight shift teams to assess. Strong
downsloping west winds will limit shower coverage east of I-25,
though still expect scattered showers and isolated thunderstorms
with cyclonic flow aloft and impressive dynamics over our northern
and western counties. A few strong to severe storms will be
possible in the afternoon across our northern Nebraska panhandle
counties.
Monday night...Cold and windy night with deep unidirectional west
winds and continued cold air advection. Areal coverage of
precipitation decreases with limited low and mid level moisture
and low level downsloping west winds.
Tuesday...Considerably cooler day based on thickness changes and 700
mb temperatures near 0 Celsius. Breezy to windy per progged low and
mid level gradients.
Tuesday night...Near to below freezing temperatures over all our
counties with cold air mass in place and decreasing winds in
advance of the next approaching shortwave.
.LONG TERM...(Wednesday through Sunday)
Issued at 230 PM MDT Sun Oct 2 2016
Confidence is increasing for some wintry precipitation Wednesday
through Thursday with the trailing upper trough deepening across
the Intermountain West. Ensemble models continue to trend colder
along with increasing chances for accumulating snow for elevations
above 5000 feet Wednesday night and Thursday. Shortwave energy
in the southwest flow aloft combined with moisture overrunning
a cold frontal surge will increase precipitation chances along
and west of Interstate 25 Wednesday. It will be cool with highs
in the 40s west and 50s southeast Wyoming and 60-65 Nebraska
panhandle.
The cold front progresses southeast Thursday with the upper trough
progressing east toward the high plains. Scattered rain/snow
showers will continue Thursday, especially along the Interstate 80
corridor. Showers will end Thursday night as subsident northwest
flow and drier air spread into the CWA. Thursday will be the
coldest day of the week with highs 30s mountains, 40s to low 50s
elsewhere. Preliminary snow accumulations Wednesday night and
Thursday vary from one to three inches along and west of Interstate
25.
Upper ridge over the western CONUS flattens with zonal flow aloft
Friday through Sunday. Rising 500-1000mb thicknesses and 700mb
temperatures with downslope low level flow will result in warming
trend toward seasonal normals.
&&
.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 603 PM MDT Sun Oct 2 2016
A few isolated showers/tstms continue to progress across areas
mainly west of the Laramie Range early this evening. These showers
may continue to develop during the course of the evening under the
the influence of broad upper level diffluence ahead of the upper
level trof. Another concern overnight is the potential for the
influx of low level moisture into the Nebraska Panhandle. Latest
observation data was showing 50 degree dewpoints starting to edge
its way into the southern Nebraska Panhandle from Northwest
Kansas. These higher dewpoints may set up the potential for IFR
ceilings overnight in KBFF,KSNY,KAIA and KCDR. The NAM is
currently showing the most signs of this taking place while the
HRRR is much more conservative. We are leaning towards the NAM at
this point. Another concern tomorrow afternoon will be the wind.
Some gusts up to 40 to 45 kts could occur in RWL tomorrow
afternoon with 25 to 35kts possible in Cheyenne and Laramie late
Monday afternoon. &&
.FIRE WEATHER...
Issued at 200 PM MDT Sun Oct 2 2016
Will need to watch our far southeast Wyoming and southern Nebraska
panhandle counties Monday for relatively low humidities and gusty
winds. Otherwise, few if any concerns expected based on projected
humidities and winds through the week.
&&
.FIRE WEATHER...
Issued at 200 PM MDT Sun Oct 2 2016
Will need to watch our far southeast Wyoming and southern Nebraska
panhandle counties Monday for relatively low humidities and gusty
winds. Otherwise, few if any concerns expected based on projected
humidities and winds through the week.
&&
.CYS WATCHES/WARNINGS/ADVISORIES...
WY...High Wind Watch from 9 AM MDT Monday through Monday evening for
WYZ104-109-111.
High Wind Watch from 9 AM MDT Monday through Tuesday morning for
WYZ106-110-116-117.
NE...None.
&&
$$
UPDATE...REC
SHORT TERM...RUBIN
LONG TERM...MAJ
AVIATION...REC
FIRE WEATHER...RUBIN
Area Forecast Discussion
National Weather Service Austin/San Antonio TX
843 PM CDT Sun Oct 2 2016
.UPDATE...
Just sent an update to re-trend forecast variables through 12Z
Monday, but no significant changes to the previous forecast and
reasoning.
&&
.PREV DISCUSSION... /ISSUED 704 PM CDT Sun Oct 2 2016/
AVIATION.../00Z TAF CYCLE/
VFR conditions are ongoing this early evening and will continue
through most of the overnight. However, patchy MVFR ceilings
11-14Z are likely in the morning as SE low-level flow for the
coastal plains to near KSAT/KSSF. NAM soundings are more robust in
the low-level moisture signal than GFS soundings but HRRR and SREF
also point towards better low-level saturation. Comparing 02/12Z
KDRT sounding - NAM appeared to initialize better vs. GFS this
morning. In addition, there could be some subtle isentropic
upglide that also aids BKN025 ceilings near KSAT/KSSF. Have placed
TEMPO group for KSAT/KSSF for the lower ceilings from 11-13Z. VFR
will prevail after 14-15Z through the day Monday. Surface winds
will increase to 10 kt from the southeast through the afternoon.
PREV DISCUSSION... /ISSUED 303 PM CDT Sun Oct 2 2016/
SHORT TERM (Tonight through Monday Night)...
Clear skies with warmer temperatures tonight as southerly winds
return across the area. Lows will range from the upper 50s across
the Hill Country to lower 60s along and east of Interstate 35.
We are anticipating another warm day on Monday with highs in the
mid to upper 80s.
There is a slight chance for showers or thunderstorms across the
far northwest part of the Rio Grande/Edwards Plateau area late
Monday night as a short-wave trough moves over the Big Bend
region.
LONG TERM (Tuesday through Sunday)...
There may be an isolated shower or thunderstorm Tuesday morning
across the Edwards Plateau area as the short-wave trough pulls to
the northeast. Rest of South-Central Texas will remain dry on
Tuesday with highs ranging from the mid 80s to lower 90s. The
Coastal Plains may see a stray shower or two or an isolated
thunderstorm Wednesday afternoon, otherwise, dry and warm weather
conditions continue through late Thursday.
An upper long-wave trough is forecast to push across the Central
Great Basin into Central Plain late in the work week. A cold
front is expected to push across the area Friday morning with low
end chances of rain across the area. The GFS solution is a bit
faster than the ECM guidance by about 6 hours or so. This forecast
package shows a blend of these two model solutions. It looks like
a progressive system with a dry airmass spreading across the area
by Friday afternoon and early evening. Rainfall amounts will be
limited to one quarter inch or less per latest guidance.
The upcoming weekend will be dry with cooler temperatures on
Saturday but warming into the mid to upper 80s on Sunday.
&&
.PRELIMINARY POINT TEMPS/POPS...
Austin Camp Mabry 63 87 68 89 71 / 0 0 0 10 -
Austin Bergstrom Intl Airport 60 87 65 89 68 / 0 0 0 10 10
New Braunfels Muni Airport 61 87 66 89 69 / 0 0 0 10 -
Burnet Muni Airport 61 84 66 85 69 / 0 0 0 10 -
Del Rio Intl Airport 65 87 69 89 70 / 0 0 0 10 0
Georgetown Muni Airport 60 86 66 87 70 / 0 0 0 10 -
Hondo Muni Airport 61 88 67 90 68 / 0 0 0 10 -
San Marcos Muni Airport 61 86 66 88 69 / 0 0 0 10 10
La Grange - Fayette Regional 63 88 67 90 72 / 0 0 0 10 -
San Antonio Intl Airport 64 87 69 88 71 / 0 0 0 - -
Stinson Muni Airport 64 88 69 90 71 / 0 0 0 - -
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
Mesoscale/Aviation...Allen
Synoptic/Grids...26
Public Service/Data Collection...33
Area Forecast Discussion
National Weather Service Marquette MI
758 PM EDT Sun Oct 2 2016
.SHORT TERM...(This evening through Monday)
Issued at 327 PM EDT SUN OCT 2 2016
Water vapor imagery and RAP analysis show a mid level low over the
Lower Great Lakes region. NW fringe of the deep layer
forcing/moisture associated with this feature was still generating a
few shra across eastern Lake Superior and far eastern Upper MI this
afternoon. The rest of the cwa has remained dry under influence of
sfc ridge whose axis is centered just west of Upper Mi.
Sfc high pres ridge will shift over the fcst area tonight, providing
a quiet night. While some lingering clouds over the e along with a
stronger ene wind just off the sfc should reduce the potential of
fog development in that area tonight, mostly clear skies and lighter
winds under ridge axis over the w and central will lead to some fog
development tonight as temps fall back blo the expected minimum dew
point readings from this afternoon. Developing upslope/onshore
easterly wind could aid fog formation over the Keweenaw. Min temps
may slip just blo 40F over the interior w tonight under best
radiational cooling. Highest readings will be along Lake Superior
where temps should mostly stay aoa 50F.
Diurnal heating will burn off fog by late morning and prominent
ridging over the region will result in a pleasant day on Monday
under mostly sunny skies. Forecast mixing to near 875 mb should
yield high temps generally in the mid to upper 60s with warmest
readings for areas along Lake Superior favored by downsloping se
winds.
.LONG TERM...(Monday night through Sunday)
Issued at 324 PM EDT SUN OCT 2 2016
Most impactful weather in the long term is fog (possibly dense) Mon
night into Tue morning. Dew points will increase into the 50s to
around 60 Mon night before coming back down Wed night, which should
lead to fog mainly over central and eastern portions of Upper MI
where upslope SSE flow and moisture off Lake michigan will be
present.
A closed low will move well NW of the CWA in the middle of the week,
which will drag upper and SFC troughs and a SFC cold front through
the CWA on Wed. This results in a quick round of showers and
possibly a few thunderstorms mainly between 12Z Wed and 00Z Thu.
Moisture cuts out behind the cold front, but the warmer than average
airmass sticks around until after a more potent upper wave and SFC
reflection move through sometime late in the week (models disagree
on timing). Widespread rain would result as the system passes.
Along and behind the upper trough, models have 850mb temps dropping
below 0C, possibly as low as -5C as the GFS suggests. However,
models disagree on magnitude and duration of the colder air and the
wind directions. Could see some snow flakes over higher terrain
areas overnight Fri and/or Sat night, but it doesn`t look like
enough to accumulate at this point.
Utilized blends for much of the forecast.
&&
.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 757 PM EDT SUN OCT 2 2016
With sfc high pres ridge over the area tonight, conditions should be
favorable for radiation fog development, more so at
IWD/KSAW. If fog does develop, LIFR conditions seem likely. Expect
improvement to VFR by late Monday morning with diurnal
heating/mixing.
&&
.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 327 PM EDT SUN OCT 2 2016
Under a weak pressure gradient across Lake Superior, winds will be
mostly under 15kt through Mon. Southeast winds will then increase
Tue/Wed as a cold front approaches. Strongest winds, up to 20-25kt,
will occur Wed over eastern Lake Superior. Cold front will pass
across Lake Superior Wed aftn/evening. W to SW winds up to 15-25kt
should occur Wed night into Thu, strongest between Isle Royale and
the Keweenaw Peninsula.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
None.
Lake Michigan...
None.
&&
$$
SHORT TERM...Voss
LONG TERM...Titus
AVIATION...JLB
MARINE...Voss
Area Forecast Discussion
National Weather Service Mount Holly NJ
909 PM EDT Sun Oct 2 2016
.SYNOPSIS...
Low pressure will weaken as it moves into New England tonight. High
pressure will build down from Canada Tuesday and Wednesday, settling
across New England and persisting through the mid week period.
&&
.NEAR TERM /UNTIL 6 AM MONDAY MORNING/...
Showers are approaching the wrn counties, but they seem to be
slowly weakening as the get closer. The latest versions of the
HRRR show the showers filling apart. The 18Z NAM wants to keep
the showers intact as they slide by. I sided more with the HRRR
and only slightly modified the POP/WX grids for the overnight.
Most areas will continue to see low clouds along with some light
fog and patchy drizzle. Winds will remain light and variable.
As for the low temperatures, we mainly used a MOS blend. The hourly
grids, such as the temperature and dew point, were adjusted with the
latest obs then the LAMP/LAV guidance was blended in through mid
evening.
&&
.SHORT TERM /6 AM MONDAY MORNING THROUGH 6 PM MONDAY/...
A closed low is forecast to gradually weaken as it crosses our area
during Monday. The day should start with areas of low clouds and
some fog then as the flow is more northwesterly enough, drying
occurs to erode the low clouds that has been around for days. This
will allow for at least partial sunshine. This however will result
in warming, and when combined with a 500 MB cold pool aloft with the
trough, some instability will be generated. The forecast soundings
overall support up to a couple hundred Joules of CAPE, however it is
low-topped and the instability profile is thin. This may not be
enough to result in lightning production. If thunder can occur,
given the cold pool aloft there could be some small hail in a few
stronger convective elements however the core of the cold pool aloft
is forecast to track just to our north. For now, we left out a
thunder mention given the low instability forecast overall and the
track of the cold pool aloft. The highest POPs, chance, were kept
across the northern areas closer to the cold pool aloft.
High temperatures were a blend of continuity and MOS, with just some
minor adjustments made thereafter.
&&
.LONG TERM /MONDAY NIGHT THROUGH SUNDAY/...
High pressure slides across to our north Tuesday and Wednesday and
settles over New England. This high will influence our weather from
Wednesday through Friday as it noses down from the northeast. We
will keep an easterly, onshore flow through this period so while it
is anticipated that we largely remain dry, it will be cooler. We may
see another round of some light drizzle and fog during this time,
more likely in our coastal zones, but overall it will be pretty
cloudy across our forecast area.
There remains considerable uncertainty with the forecast as we head
into the weekend, due to Hurricane Matthew and its potential track.
Model guidance does show that we will see some increase in wind
speeds and potentially some rains from Matthew as its skirts by to
the east of our area. Just how close Matthew gets will need to be
monitored as it will certainly change any impacts across our area.
For now, have upped the wind speeds, especially over the coastal
areas, and will continue to mention rain in the forecast.
&&
.AVIATION /01Z MONDAY THROUGH FRIDAY/...
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY and surrounding areas.
Tonight...A batch of clearing and VFR conditions tried to move NE
across the area earlier. ILG and PHL went VFR for a time, but the
clouds/inversion now seem to be winning as the low clouds are
creeping back over those (previously VFR) areas. Most areas will
likely be LIFR/IFR overnight. Patchy drizzle and fog expected as
like the past few nights. Amds expected overnight.
Monday...IFR/MVFR to start, however conditions are expected to
improve to VFR by 15z. A few showers around especially in the
afternoon, however coverage looks low. Winds becoming north-
northwest around 5 knots during the morning.
OUTLOOK...
Monday night...Mainly VFR conditions expected. Possibly lowering
overnight Monday into early Tuesday morning. Small chance of showers.
Tuesday through Friday...MVFR/IFR conditions with low clouds and fog
possible across the terminals. Easterly winds with gusts up to
15 knots, 20 to 30 knots possible towards the coast.
&&
.MARINE...
The onshore flow has turned light and this will continue through
tonight, then it should turn more north-northwest Monday morning
before turning east-southeast in the afternoon (especially across
the northern coastal waters). The conditions are expected to remain
below Small Craft Advisory criteria through Monday.
OUTLOOK...
Monday night...Sub-Small Craft Advisory conditions expected.
Tuesday through Friday...An extended period of Small Craft Advisory
conditions expected to develop Tuesday and persisting through the
week. Seas will rise above 5 feet by Tuesday afternoon and remain
between 5 to 10 feet through at least Friday. Strong northeast winds
will develop on Tuesday and continue through at least Friday.
Winds may gust near gale force, especially Thursday and Friday.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...None.
NJ...None.
DE...None.
MD...None.
MARINE...None.
&&
$$
Synopsis...Meola
Near Term...PO
Short Term...Gorse
Long Term...Meola
Aviation...Gorse/Meola/PO
Marine...Gorse/Meola
Area Forecast Discussion
National Weather Service Reno NV
847 PM PDT Sun Oct 2 2016
.UPDATE...
A large area of precipitation has spread across northeast
California and the northern Sierra and is spilling over into
western Nevada. This precipitation shield is remnants of
convection which occurred earlier today near Chico, CA. While it
is not nearly as strong as it was earlier, there are a few
embedded thunderstorms. The convective nature of this
precipitation has lead to snow levels lowering, then wet bulb
cooling lowered snow levels even more. We have had reports in the
north Reno valleys around 5000 feet of up to a half inch of snow
and it has just begun to accumulate at the NWS Reno office. We
even had a report of accumulation down to 4350 feet in Graeagle,
CA! Most roads have only been briefly snow covered, but as cold
air advection continues overnight, anywhere roads are wet there
could be icy conditions. This is especially true in the Sierra.
There are also showers in the Sierra from South Lake Tahoe south
to Bridgeport, but these are more scattered in nature. Some brief
blips of lake enhancement off of Lake Tahoe have also been present
and luckily have crossed over the area where the Frontage Fire is
burning.
The biggest question this evening is how long will the large
precipitation shield near the I-80 corridor last? There is a
clear back edge to it, but the forward progress is continuing to
spread south and eastward. Have updated the forecast this evening
to increase precipitation chances under this region and add a
larger rain/snow mix to the forecast as convection and wet bulb
cooling have lead to a wide range of snow reports at various
elevations. -Dawn
&&
.PREVIOUS DISCUSSION... /Issued 255 PM PDT Sun Oct 2 2016/
SYNOPSIS...
A cold trough moves into the West Coast today bringing gusty winds
and temperatures well below seasonal averages along with the threat
for lower valley freezes through mid-week. Valley rain and mountain
snow showers are expected tonight and Monday night, with light
snow accumulations possible over the Sierra passes this evening.
Temperatures will warm back to near average by Friday.
SHORT TERM...
The main forecast concerns today are winds and humidities through
this evening (mainly along/south of I-80), possible slick conditions
over northern Sierra passes this evening, and sub-freezing temperatures
for the lower valleys of western Nevada in the next few nights.
Low pressure is dropping into northern California this afternoon
and a wind shift has moved into western Nevada. However, little
change in temperature or moisture has accompanied the shift so
believe the main surface front to be with a band of precipitation
(and solid wind shift/temperature change) nearing the northern
Sierra early this afternoon. Some light rain has moved into Lassen
and Plumas Counties this afternoon with a wet road indicated by
web cams over Fredonyer Summit. Wind-wise, gusts between 25 and 35
mph (locally 40-45 mph) are widespread for eastern California and
far western Nevada this afternoon. These winds should continue
well into evening. However, humidities should begin to recover
(and already have north of Tahoe in CA) as colder air filters into
the region. For more, see the fire weather discussion below.
Precipitation-wise, the initial frontal band of precipitation
should go through quickly. Because precipitation is moving into
the northern Sierra in the daytime, roads should remain mostly wet
even over the crest (where snow will fall) due to well above
freezing road surfaces. The main concern is between about sunset
and 11 PM in the northern Sierra (down to about Ebbetts Pass) when
widespread snow showers are expected under the upper low. The HRRR
model continues to show locally heavy convective showers.
However, it is hard to predict where narrow heavier bands will
form and threaten slushy accumulations over Tahoe/Alpine County
passes. Motorists should be prepared for slow travel over I-80, US
50, and for Mt Rose highway if they must wait until after dark to
travel.
Showers should taper off rapidly by midnight in the northern Sierra
as the upper trough axis passes to the east. Any slushy conditions
in the northern Sierra should abate quickly once showers taper off.
Outside of the northern Sierra, only a brief shot at some light
showers is expected tonight mainly just ahead of the trough axis.
Turning to freezing temperature concerns, the latest HRRR is casting
doubt that winds will calm down sufficiently or skies will remain
clear long enough for a widespread freeze (locally defined as 30
degrees or less) in western Nevada tonight. Still, with the colder
air filtering in valley temperatures should fall into the 30s to
around 40 even if they remain mixed so it won`t take much for a
dip to 30 degrees or so for a couple hours. Therefore, the freeze
warning for suburban and outlying valleys of far western NV will
remain up for late tonight and Monday morning.
Monday, a period of warm air advection/isentropic ascent is expected
Monday afternoon and evening. This will bring the threat for some
light showers, with snow levels rising generally above 7000 feet
by late in the day. No road impacts are expected as the showers
should be fairly light and the time of day is not ideal for road
accumulations.
Another brush-by system could bring a few more showers north of
I-80 Tuesday. However, the main focus will be late Tuesday night
and Wednesday morning temperatures for the lower valleys of
northeast California and western Nevada. Tuesday morning looks a
bit mixed up with a moist low level atmosphere so widespread
freezing temperatures are not expected. Wednesday, and especially
Thursday morning is a different story as drier air begins to
filter into the area with slackening winds. At this time, it looks
like Wednesday and/or Thursday morning will finally bring
widespread below freezing temperatures to many areas of western
Nevada. Snyder
LONG TERM...Thursday through Sunday...
The long-term forecast calls for dry conditions Thursday through
Sunday with the storm track north of the Oregon border. Model
simulations do show weak impulses crossing the Sierra and western NV
from west to east which could create periods of mid-to-high level
cloudiness, mainly north of highway 50. There is a chance one of
these impulses could bring a period of showers north of Susanville,
but overall moisture looks to be quite limited so we maintained the
chances for precipitation less than 15%. Some model simulations
advertise a Pacific trough approaching the west coast Sunday which
could bring an increase in moisture to the Sierra by Sunday night (a
week from tonight), but this is a minority opinion.
A slow warming trend of afternoon highs is forecast Thursday through
Saturday or Sunday, although cloud thickness is a variable that could
possibly temper that trend. Highs for Saturday and Sunday could warm
into the mid to upper 70s in western NV and upper 60s to low 70s for
Sierra communities. JCM
AVIATION...
A cold front passage is creating gusty west winds through this
evening with peak gusts 30-40 kts from the lee of the Sierra out
into western Nevada and far northeast California. Expect Sierra
ridges to see gusts up to 60 kts through this evening along with
moderate turbulence near and in the lee of the Sierra.
A mix of rain and snow this evening could bring an inch or so of
slushy accumulation to KTRK and KTVL. Cigs/vsbys into the MVFR/IFR
range in the northern Sierra and northeast California are also
expected through this evening. To the east and south rain and snow
showers will be more scattered in nature but with IFR conditions
possible near the Sierra crest in Mono county. VFR conditions are
likely in western Nevada...but with some mountain obscurations.
Snow in the Sierra will taper off to showers by midnight. Showers
could linger into Monday as well and possibly Monday night north of
I-80. Ceilings should improve Monday and winds will be lighter. Light
precipitation is possible north of I-80 Tuesday and
Wednesday...but conditions should be no worse than MVFR. 11/20
FIRE WEATHER...
Gusty winds will continue into the early evening hours, as a cold
front pushes through the region. Red Flag Warning remains in place
for Mono-Alpine-Southern Lyon and Mineral Counties through 6PM.
Moisture is increasing to the north of Reno-Tahoe, with precipitation
and clouds already moving into the Truckee-Tahoe area. Wind gusts
of 35-45 mph have been observed so far this afternoon for all
areas, but the strongest winds have been mainly south of Carson
City and down to Mammoth Lakes. Drier conditions exist south of
Carson City with humidity in the low teens and even down to near
5% as you get near Mammoth Lakes/Benton/Bishop. Areas of critical
conditions have also expanded slightly further north to near
Minden/Gardnerville where firefighters are responding to a new
wildfire near Dresslerville and Highway 395.
Low pressure moving into northern CA/NV today will bring moisture
and showers into the Northern Sierra and Lake Tahoe Basin through
this evening. Snow levels will drop to around 5500-6000 feet this
evening, bringing light snow accumulations of up to a few inches to
the Northern Sierra above 7000 feet (mainly north of Ebbetts Pass
all the way north to Lassen Park and the Warner Mountains.
Breezy northwest flow will continue over the next couple days with
temperatures slowly warming each day. Lighter winds are expected by
Wednesday and Thursday as high pressure builds back over the region.
Hoon
&&
.REV Watches/Warnings/Advisories...
NV...Freeze Warning from 2 AM to 8 AM PDT Monday NVZ003.
CA...Freeze Warning from 2 AM to 8 AM PDT Monday CAZ071.
&&
$$
For more information from the National Weather Service visit...
http://weather.gov/reno
Area Forecast Discussion
National Weather Service Dodge City KS
245 AM CDT MON OCT 3 2016
.SHORT TERM...(Today and tonight)
Issued at 223 AM CDT Mon Oct 3 2016
Breezy conditions this morning will become windy in the afternoon
as mixing deepens and gusts increase to the 30 to 40 knots range.
This will be partially a result of deepening low pressure across
northeast Colorado through the day in response to the approaching
Pacific low pressure now diving though Nevada. Highs reaching the
mid 80s are expected this afternoon, with more mild lows again
tonight, ranging from mid 50s west to the mid 60s in the central
Kansas counties. Slight chances for shower and Thunderstorms will
be carried over through the overnight as an instability/moisture
axis works its way across the area. However the better chance for
convective initiation supporting severe storms appears more likely
on Tuesday afternoon, in the extreme eastern counties, as the
cold front moves across the area.
.LONG TERM...(Tuesday through Sunday)
Issued at 223 AM CDT Mon Oct 3 2016
Cooler conditions area are forecast following the cold front. A
secondary vort lobe rotates out of the west Wednesday night and
Thursday, reinforcing a cooler airmass for late in the week.
Temperatures may not exceed the 60s Friday, setting up a fall-
like weekend with highs in the 70s. In the meantime, cold dry air
will be in place late Thursday night. Lows aren`t forecast to
freeze, however mid to even low 30s are possible across west -
central Kansas.
&&
.AVIATION...(For the 06Z TAFS through 06Z Monday night)
Issued at 1225 AM CDT Mon Oct 3 2016
The main change for aviation and terminal concerns will be the
stronger winds in the coming 24 hours. A much stronger gradient
is setting up which will bring 25 to 30 knot sustained winds and
near 40 kt gusts by later in the day, and maintain much of their
momentum though tonight. Ceilings should not be much of an issue
although the HRRR develops MVFR category clouds perhaps across the
Garden City and Dodge areas later this morning, which may include
a few isolated showers.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 86 62 78 46 / 10 20 10 0
GCK 87 58 75 42 / 20 20 10 0
EHA 88 55 75 43 / 10 10 0 0
LBL 87 61 78 44 / 10 20 10 0
HYS 83 61 74 45 / 10 30 20 10
P28 82 65 80 53 / 0 50 40 20
&&
.DDC Watches/Warnings/Advisories...NONE.
&&
$$
SHORT TERM...Russell
LONG TERM...Russell
AVIATION...Russell
AREA FORECAST DISCUSSION
National Weather Service Des Moines IA
339 AM CDT Mon Oct 3 2016
.SHORT TERM.../Today/
Issued at 339 AM CDT Mon Oct 3 2016
For the third consecutive day the primary forecast challenge is fog
trends during the early morning hours, with clearing and mild
weather expected thereafter. The large surface ridge that was draped
across Iowa last night has moved off to the east but not as far as
expected, resulting in continued very light winds across the
forecast area this morning. Fog initially developed in our
southeastern counties and has been slowly spreading northwest into
central Iowa. Low level flow trajectories and HRRR depictions
support a continuation of this trend, and it is likely that we will
again see a significant increase in fog coverage for a brief period
between about 11Z and 13Z. However, only two or three stations in
Iowa have reported quarter mile visibility to this point and given
the limited dense fog threat in time and space, no advisory is
anticipated. The expected expansion of fog just before sunrise may
be handled by special weather statements again if warranted.
.LONG TERM.../Tonight through Sunday/
Issued at 339 AM CDT Mon Oct 3 2016
No real changes to previous forecasts...active weather expected in
the extended with two major systems affecting the Central Plains
this upcoming week. Though tonight will be relatively quiet over
central Iowa...clouds will be on the increase from the system approaching
from the west. Subjective 00z H850 analysis last evening showed upstream
large scale trough and associated dual shortwaves over the Rockies
at this time. The leading wave over eastern Colorado is already
tapping into a broad zone of warm air advection and moisture from
western Texas northward to Nebraska. A warm front aloft is beginning
to create a shield of clouds over the high Plains...and these will
eventually move east into western Iowa overnight tonight as strong
warm air advection...height falls associated with leading wave and
vort max all aid lift overnight across Nebraska. The line of storms
expected to move east/northeast will weaken as it moves into Central
Iowa Tuesday morning...only to strengthen as a second and stronger
wave over the southern Plains drives northeast from the Texas
Panhandle to western Iowa by 00z Wednesday and western Wisconsin
by 12z Wednesday. This will help push a cool front across the
region overnight Tuesday night/Wednesday morning with convection
likely all night. Though the most robust convection is likely to
remain south of Iowa Tuesday afternoon and weaken somewhat as it
moves northeast overnight...some concerns remain. Both the Euro
and GFS forecast the strength of the low level jet to approach
50kts Tuesday evening...MUCAPE of 400-800 j/kg and a gradient of
0-3km SRH values of 300-400 m2/s2 somewhat ahead the leading edge
of the convective line as it enters western Iowa. There are some
slight differences in the timing of the upper level forcing versus
the lower level forcing which may reduce the overall threat of
severe weather. This high shear/low cape environment needs to be
watched for the potential of a tornado risk with the passing line
of storms. Currently the area is outlooked for a marginal risk of
severe storms Tuesday evening. PWATS are in the 1.5 inch range so
there will be the potential for brief heavy rainfall. Through at
least Tuesday and lingering into Wednesday highs will be generally
well above normal in the 70s. There continues a consistent signal
for a stronger shortwave...one off the Oregon coast at 18z Tuesday...
to rapidly strengthen and move into Iowa by Thursday afternoon.
Another but weaker shortwave will precede this Wednesday night
into Thursday morning. Several rounds of thunderstorms will be
likely from late Wednesday night into Thursday with elevated
convection likely Wednesday night and potentially surface based
convection over portions of southeast Iowa Thursday afternoon.
There is still considerably differences between the GFS and Euro
solutions on Thursday...though both indicate a strong signal for
thunderstorms and some severe potential. PWATS again approach 1.5
inches with this system so another round of potentially moderate
to briefly heavy rainfall may occur. Averages over the region this
week may range from 0.5 to nearly 2 inches. Will better define the
amounts closer to each event. Highs will be cooler on Thursday
with the exception of the southeast which may still be in the warm
sector. Otherwise...the weekend from Friday through Sunday more
fall like with seasonal highs and lows along with generally dry
weather. A weak upper level system may spread some clouds and a
few light showers across the region over the weekend...but with
uncertainty and a weak signal in the models will leave out of the
forecast for now.
&&
.AVIATION.../For the 00Z TAFS through 00Z Monday evening/
Issued at 651 PM CDT Sun Oct 2 2016
Light and variable winds and clearing skies from the north will
provide enough radiational cooling tonight and thus expecting some
fog development past 09z Monday. Lower confidence in how dense the
fog will become, so left mention of only MVFR visibility attm.
Mixing develops Monday afternoon and introduced wind gusts near 20
knots.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Lee
LONG TERM...REV
AVIATION...Podrazik
Area Forecast Discussion
National Weather Service Grand Forks ND
359 AM CDT Mon Oct 3 2016
.SHORT TERM...(Today and tonight)
Issued at 359 AM CDT Mon Oct 3 2016
The main forecast challenge will be pcpn chances, starting with
what is going on early this morning. Since midnight, a cluster of
tstms has been lifting northeast through the Grand Forks area.
This seems to be associated with low level warm advection and the
low level jet. The HRRR lingers this activity in the northern Red
River Valley up toward the northwest angle of MN into mid Monday
morning, before it lifts into southern Canada. Then the rest of
the day should be dry, with the attention shifting to increasing
wind speeds. A pretty healthy 850mb jet develops through the late
morning, but mainly for areas west of the FA. Not expecting
advisory criteria wind speeds, but just below, so it will be a
windy afternoon along and west of the Red River Valley. Not a lot
of drop off in the thermal fields today, and with the gusty south
winds expected, going to go on the higher side of guidance for
highs today. This would have highs fairly similar to yesterday, or
areas in the southern FA close to 80F again. The 850mb jet cranks
up even more tonight, helping to spread more moisture and pcpn
northward into the FA. Despite this, pcpn amounts on the models
are on the lighter side tonight.
.LONG TERM...(Tuesday through Sunday)
Issued at 359 AM CDT Mon Oct 3 2016
Still looks gusty into Tuesday, as the sfc low lifts into
southeast Saskatchewan. This will push the steadier pcpn into MN
during the day. There is a ribbon of instability associated with
this, but at this point the stronger values stay south of the FA.
Therefore pcpn amounts still look fairly light. This changes
somewhat by Tuesday night as the low level jet cranks up again.
Most models show one to two inches of rain up into the eastern FA,
from Wadena to Bemidji. As the sfc low tracks across Manitoba
and on northeast Wed into Wed night, winds turn west then
northwest and stay on the gusty side. There may be a little light
pcpn up along the Canadian border, but most models look dry.
Thursday to Monday will provide a roller coaster of temperatures as
the period starts off below normal for the end of the week before
rebounding to above normal for the start of next week. Upper level
trough will slowly propagate across the Northern Plains thursday and
Friday with 850mb temps falling into the 0 to minus 5C range. This
will bring the first round of widespread freezing temps so far this
fall on Friday and or Saturday morning. Clouds and winds still to
have an impact in the timing and details, nonetheless the airmass
will be very cool compared with recent weather as highs struggle to
near 50F on Friday. Temps do begin to moderate on Saturday some with
50s expected to turn to mid 60s by next Monday. Mostly dry weather
is expected with a few showers possible Saturday.
&&
.AVIATION...(For the 06Z TAFS through 06Z Monday night)
Issued at 1052 PM CDT Sun Oct 2 2016
Generally VFR conditions expected during the forecast period. An
isolated shower or thundershower is possible across northeast ND
and the far northern Red River Basin through overnight. Scattered
showers and thunderstorms should redevelop into the Devils Lake
Basin through the day on Monday.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...None.
MN...None.
&&
$$
SHORT TERM...Godon
LONG TERM...Godon/JK
AVIATION...Gust
Area Forecast Discussion
National Weather Service Marquette MI
451 AM EDT Mon Oct 3 2016
.SHORT TERM...(Today and tonight)
Issued at 450 AM EDT MON OCT 3 2016
Water vapor imagery and RAP analysis show that the mid level low
that was centered near Detroit 24hrs ago has weakened and is now
over Lake Ontario. A deep trof has moved over the western CONUS, and
downstream of this feature, a ridge extends from the southern Plains
to northern Ontario. This ridge and the associated sfc high pres
centered over se Hudson Bay and ridging ssw across the Upper Lakes
are providing a tranquil early morning across the fcst area. With
clear skies and calm winds, temps have fallen down into the 30s at
the traditional cold spots. Some fog has also developed and has been
most persistent and more widespread over far western Upper MI.
Otherwise, up to this point, fog that has developed across the area
appears to be patchy/shallow as suggested by widely varying vis at
some obs locations and by satellite imagery which does not show much
indication of fog other than over far western Upper MI. To the ne, a
large are of stratus has advanced sw across northern Ontario to the
n and ne shoreline of Lake Superior.
Since fog is mostly patchy/shallow, expect the fog to burn off
during the morning hrs. Models indicate that low level winds should
veer sufficiently to the e and se quickly enough this morning so
that the stratus advancing toward northern and eastern Lake Superior
should begin to be pushed w and then nw before reaching the fcst
area. Still, will be something to monitor during the morning. The
developing e to se wind may bring some low clouds off Lake MI into
the far south central fcst area later today. Otherwise, it appears
abundant sunshine should mostly prevail. Fcst soundings suggest max
temps generally in the upper 60s to around 70F, a nice early Oct
day.
Tonight, s to se low-level winds will increase as sfc high pres
ridge shifts e and pres gradient tightens. Given the abundant low-
level moisture present over Lower MI into northern IN/IL and the
additional moisture that will be picked up off the relatively warm
Lake MI waters, expect low clouds/fog to develop tonight as this
warmer/moister air upslopes into the cooler conditions over Upper
MI. Fog should be most widespread and become denser over the central
fcst area, roughly in the area bounded by Crystal Falls, Ishpeming,
Escanaba and Menominee where upsloping will be most pronounced.
Nearly every model is generating light pcpn in this area late
tonight. Given the fairly shallow sfc based moisture layer, any pcpn
that occurs should be -DZ, and fcst will reflect this idea in the
area mentioned above where upsloping is strongest.
.LONG TERM...(Tuesday through Sunday)
Issued at 412 AM EDT MON OCT 3 2016
A warm, moist sly flow ahead of an aprchg cold fnt wl result in a
good deal of lo clds on Tue along with some fog/drizzle especially
over the scentral in the mrng. A shrtwv/sfc lo pres lifting ne fm
the Plains into scentral Canada wl drag a weak cold fnt acrs the Upr
Lks on Wed, accompanied by a band of showers. Although there wl be a
brief drying trend on Wed ngt behind the fropa, another disturbance/
lo pres lifting newd within the larger sw flow alf btwn a rdg over
the se CONUS and troffing over the w wl bring another round of
showers later on Thu into Fri. Temps wl remain above normal into
Fri. The arrival of cooler air behind the lo pres could cause some
lk effect showers late Fri into Sat before hi pres blds into the
area later in the weekend and causes a drying trend.
Tue/Tue ngt...Upr MI wl be dominated by a steady/gusty sly flow with
h925 winds incrsg to 40 kts under tight pres gradient btwn sfc hi
pres over New England/the Cndn Maritimes and a deep lo pres moving
newd fm the nrn Plains into Manitoba ahead of a vigorous shrtwv
lifting out of a deep upr trof over the wrn CONUS. As this sly flow
taps incrsly moist llvl air under a subsidence invrn just blo h85,
expect a good deal of lo clds away fm the downslope areas near Lk
Sup. With upslope flow off Lk MI, maintained fog fcst on Tue mrng
and added some patchy drizzle over the scentral where a number of
the models show some lgt qpf. But mid lvl dry air associated with
slowly departing upr rdg dominating ern NAmerica wl prevent more
substantial pcpn until at least late Tue ngt, when the warm conveyor
belt mstr ribbon/axis of pwat aprchg 1.50 inches ahead of cold fnt
attendant to lo pres moving thru Manitoba wl drift into the far wrn
cwa. Temps wl be well above normal as h85 temps over the far w are
fcst as hi as 12C within the strong sly flow.
Wed...Shrtwv/lo pres over Manitoba are fcst to continue to the ne
into far nw Ontario and aprchg Hudson Bay by 12Z Thu. The attendant
cold fnt/warm conveyor belt mstr ribbon/axis of deep lyr qvector
cnvgc wl cross the Upr Lks on Wed accompanied by a band of showers/
perhaps a TS. Even though pwat near 1.50 inches wl be 200-250 pct of
normal, passage of the stronger shrtwv well to the nw and quick
moving fnt/warm conveyor belt wl limit pcpn totals. Vigorous deep
lyr drying/deep lyr qvector dvgc in the wake of the fropa wl end the
pcpn and even allow a return of some sunshine by late in the day
over the w. Since the airmass following the fropa wl be Pacific in
origon under a sw flow aloft btwn the lingering wrn trof and the
persistent upr rdg over the se CONUS, temps wl remain above normal.
Wed ngt...Weak rdg of hi pres/mid lvl drying air following the fropa
wl bring a period of dry wx. But with h85 temps falling no lower
than about 8C and a steady wsw wind, temps wl remain above normal
despite expected clr-pcldy skies.
Thu into Fri...Lo pres is fcst to dvlp on Wed ngt over the central
Plains as a disturbance over the srn Rockies within the wrn trof
begins to lift to the ne. Except for the 00Z GFS, medium range
guidance had come into fairly good agreement showing the shrtwv/sfc
lo pres moving to the ne, reaching the Upr Midwest on Thu and
crossing Upr MI Thu ngt before exiting into Ontario on Fri. The 00Z
GFS on the other hand shows the shrtwv and a weaker lo pres aprchg
fm the sw and then exiting to the ne at a slower pace. Since this
new GFS run is quite different fm previous runs as well as the most
recent GFS ensemble fcst, suspect the 00Z Cndn/12Z ECWMF models are
on the right track. Those fcsts would sug a period of likely pops
beginning late Thu until the early mrng hrs on Fri for at least a
portion of the cwa would be warranted as the vigorous dynamic
forcing interacts with pwat fcst as hi as 1.50 inches. After the lo
shifts to the n on Fri, cooler air wrapping into the area could
cause some lk effect showers under the cyc nw flow left in the wake
of the departing lo pres, especially over the nw cwa, depending on
the degree of llvl drying.
Extended...Some lk effect showers, that could be mixed with some sn
at least over the hier terrain, wl be psbl especially over the hier
terrain of the nw cwa into Sat as h85 temps fall toward -3 to -5C in
the cyc wnw flow left in the wake of the lo pres exiting thru
Ontario. Right now, it appears sfc temps in the areas that would be
impacted by the lake effect showers wl be too warm to include a
specific mention of snow showers attm. Hi pres aprchg fm the nw in
the wake of the exiting shrtwv/sfc lo pres under rising hgts should
bring a drying trend for Sun/Mon. Temps at the start of the weekend
wl be near normal, but readings should return above normal early
next week under the sw flow left in the wake of the passing hi pres
rdg.
&&
.AVIATION...(For the 06Z TAFS through 06Z Monday night)
Issued at 130 AM EDT MON OCT 3 2016
With a sfc high pres ridge over the area overnight, conditions will
be favorable for radiation fog development, especially at KIWD/KSAW.
However, the shallow fog will result in variable vsby at times with
conditions varying btwn IFR and LIFR. Expect improvement to VFR by
late morning with diurnal heating/mixing. Fog may again be possible
tonight but should hold off until after 06z.
&&
.MARINE...(For the 4 AM Lake Superior forecast issuance)
Issued at 450 AM EDT MON OCT 3 2016
Winds today will be mostly under 15kt with sfc high pres ridge over
the Upper Lakes. As this ridge shifts e and a cold front advances
across the Plains, SE to S winds will gradually increase tonight
thru Wed. Winds will become strongest over central and eastern Lake
Superior, reaching the 20-30kt range Tue night into Wed. The cold
front will pass across Lake Superior Wed aftn/evening. While W to SW
winds up to 15-25kt should occur behind the front Wed night into Thu
morning, strongest between Isle Royale and the Keweenaw Peninsula,
pres gradient and winds will weaken for a time Thu aftn/evening as a
low pres trof develops over the Upper Lakes ahead of a low pres wave
developing over the southern Plains. After this low pres wave passes
Thu night, NW winds up to 20-25kt will develop on Fri.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
None.
Lake Michigan...
None.
&&
$$
SHORT TERM...Rolfson
LONG TERM...KC
AVIATION...JLB
MARINE...Rolfson
Area Forecast Discussion
National Weather Service Morristown TN
342 AM EDT MON OCT 3 2016
.SHORT TERM (Today and Tonight)...
Current water vapor imagery and RAP upper air analysis indicates a
closed low moving into the Northeastern U.S. as a ridge amplifies
across the Northern Plains and Great Lakes region. Closer to home, a
weak upper level wave can be noted to the east of the mountains with
widespread mid to high clouds across the Carolinas. At the
surface, a broad area of weak high pressure exist across much of
the Southeastern U.S. These upper level and surface features have
lead to mostly clear skies and light winds across the area. Due to
this, expect some areas of patchy fog this morning. Any ongoing fog
will quickly dissipate this morning after daybreak.
For today, PW values remain slightly below normal with values
ranging from 0.8-1.0 inches. The upper level closed low will
continue to drift slowly to the southeast across the Northeastern
U.S. as the ridge amplifies across the Great Lakes. Some clouds are
expected today with weak cyclonic flow in the mid and upper levels.
Otherwise, temperatures will be a couple of degrees warmer than
yesterday with highs topping out in the mid 70s to low 80s across
most valley locations.
.LONG TERM (Tuesday through Sunday)...
The Southern Appalachian Region will remain in a quiet weather
pattern through the early part of the extended with high pressure
the dominant feature. This will allow for continued dry conditions
and warming trend with afternoon highs Tuesday through Thursday
reaching into the upper 70s and 80s across the Tennessee Valley.
There continues to be model inconsistencies late in the period and
confidence is low. However ...the overall pattern has remained
consistent with a weakening frontal boundary moving in from the
west and a tropical system tracking along the east coast. The ECMWF
continues to be the faster model...bringing the front through
Friday night into Saturday... while the GFS is slower with the
frontal passage late in the day Saturday. Both models have trended
drier and expect little low level moisture to accompany the front.
By Sunday...the ECMWF builds in a ridge of high pressure behind the
front...while the GFS wants to track the upper low a little north
of the TN/KY border. The models have been fairly consistent with
precip from the tropical system staying east of the area. With all
of this...the current forecast probably the most reasonable way to
go and will make little change to the forecast. Thus...the forecast
will be dry Friday through Sunday.
&&
.PRELIMINARY POINT TEMPS/POPS...
Chattanooga Airport, TN 83 60 85 61 / 0 0 0 10
Knoxville McGhee Tyson Airport, TN 81 58 82 59 / 0 0 0 10
Oak Ridge, TN 80 58 82 59 / 0 0 0 10
Tri Cities Airport, TN 77 56 80 55 / 0 10 10 10
&&
.MRX WATCHES/WARNINGS/ADVISORIES...
NC...None.
TN...None.
VA...None.
&&
$$
MA/MJB
Area Forecast Discussion
National Weather Service Norman OK
432 AM CDT MON OCT 3 2016
.DISCUSSION...
Current convection is staying north of the 37th parallel and
drifting northeast. the rap hints at some showers possible in the
west early this morning, but it is the outlier and will not put
POPs in for this morning at this time.
Higher storm chances are expected to develop late tonight. The
models (especially the ECMWF) have been a little less aggressive
with the overnight development, but still expected to see
scattered storms developing. As the upper trough approaches on
Tuesday, the vort max is well timed to support storm development
tomorrow afternoon. Forecast instability and shear will be
sufficient to produce some severe storms, although there still are
a couple of questions about how strong of a severe storm
potential. First is low-level moisture quality. Winds are still
blowing offshore along the Texas Gulf coast this morning, although
mid-upper 60s dewpoints are lurking along the coast. Low level
southerly flow will increase today and tonight advecting the
better moisture north, but the higher dewpoints may still be a
late arrival. The second question is what affects morning
convection will play on the surface pattern and the developing
instability, but with models hinting at less-widespread convection
in the morning, this may be less of an issue. Agree with SPC`s
enhanced risk of severe storms across the west for Tuesday
afternoon and evening.
The trends in the models also now indicate more of a separation in
time between the first trough moving through over the plains
Tuesday and the approach on Thursday night/Friday of the next
trough that develops in the western U.S. With this timing, the
storms with the first wave will move out Tuesday night or early
Wednesday morning, with storm chances redeveloping Wednesday
afternoon and becoming more widespread Thursday and Thursday night
with the approach of the second trough. But these models have also
been changing the scenario over time, so we will see how it plays
out.
&&
.PRELIMINARY POINT TEMPS/POPS...
Oklahoma City OK 82 65 83 64 / 10 10 40 40
Hobart OK 84 65 84 58 / 0 30 40 20
Wichita Falls TX 85 66 87 66 / 0 20 30 20
Gage OK 83 64 85 49 / 10 30 20 10
Ponca City OK 84 65 84 61 / 10 20 50 50
Durant OK 85 61 86 68 / 0 0 10 30
&&
.OUN Watches/Warnings/Advisories...
OK...None.
TX...None.
&&
$$
Area Forecast Discussion
National Weather Service Mount Holly NJ
340 AM EDT Mon Oct 3 2016
.SYNOPSIS...
Low pressure will weaken as it moves into New England
tonight...sliding off shore on Tuesday. High pressure will build
down from Canada mid week and persist through much of the rest of
the work week.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
The pesky upper low will finally begin its exit from the region.
However, before it does, we will be looking at one more day of low
clouds. Then, a cold front will pass through the area, and this
front could bring some passing showers.
Latest radar showed some showers over nrn NJ that were dissipating
as they moved out of the area. Another batch was located alg the
MD/PA brdr and into nrn DE these were weakening, but the HRRR had
them dissipating which they are showing no sign of doing attm. SO
will carry low pops for a few hours. Then, pops shud be low this
aftn assocd with fropa.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH 6 AM TUESDAY/...
Behind the front tonight, there should be some gradual improvement
as high pres slowly builds in.
&&
.LONG TERM /TUESDAY THROUGH SUNDAY/...
Tuesday...models slowed it down a bit, but the persistent upper
level low that has been responsible for the cloudy and damp
weather the last several days should finally be off shore on
Tuesday. In its wake, an upper level short wave ridge and a
surface high will build towards our region. With the center of the
surface high over ME/NB, onshore flow should develop once again
which may mean persistent low clouds Tuesday into Tuesday night
(unlike with last week, mid and upper levels should remain quite
dry, so don`t expect much precip and the cloud deck should be as
expansive or persistent as what we just saw).
Wednesday through Friday...in a shift from previous model runs, it
looks like we will see considerable breaks in clouds despite the
fact that the onshore flow should persist through this period due
to the surface high remaining to our northeast. This looks to be
partially due to very dry mid and upper levels, and partially due
to the subsidence with the associated short wave ridge. Even with
more sunshine, it should still be relatively cool thanks to the
onshore flow.
Saturday through Monday...The concern through this period is what
happens with Hurricane Matthew. There remains considerable
uncertainty with the track of Matthew (both in how quickly it will
propagate and exactly what track it will take). When, how close,
or even if Matthew will approach our region is still very
uncertain. For now have gone with a blend of the guidance and
previous forecast, and kept a mention of chance of rain through
out this period. Please monitor the National Hurricane Center for
the latest forecast track information on Hurricane Matthew.
&&
.AVIATION /07Z MONDAY THROUGH FRIDAY/...
The following discussion is for KPHL, KPNE, KTTN, KABE, KRDG, KILG,
KMIV, KACY and surrounding areas.
IFR and LIFR conds prevailed early this mrng in a combination of low
clouds and fog. The real dense fog was not lasting in any one
location, but the low clouds were. Expect gradual improvement durg
the day.
a cdfnt will cross the area by late mrng erly aftn, and that shud
scour things out and return things to VFR.
Wind will genly be light n to nw today and become nely tonight with
speeds around 5 kts.
Outlook...
Tuesday...low clouds are once again possible with ceilings in the
MVFR and IFR categories
Wednesday and Thursday...low clouds are expected to dissipate
on Wednesday leaving mostly VFR conditions.
Friday...A very uncertain forecast dependent on the eventual track
and progress of tropical cyclone Matthew. At this point, the highest
risk for both low clouds and breezy conditions will be for Coastal
Plains TAF sites (KMIV and KACY).
&&
.MARINE...
No marine headlines are anticipated through the near and short term
pds. Seas will be 3 to 4 ft. WInd will increase to around 20 kts
by the end of the pd.
Outlook...
Tuesday through Friday...breezy northeasterly winds are expected to
develop on Tuesday, and seas will subsequently increase. SCA
conditions are likely to develop by late Tuesday. Even though winds
may decrease on Wednesday, seas may stay above 5 feet through at
least Friday.
&&
.PHI WATCHES/WARNINGS/ADVISORIES...
PA...None.
NJ...None.
DE...None.
MD...None.
MARINE...None.
&&
$$
Synopsis...Johnson
Near Term...Nierenberg
Short Term...Nierenberg
Long Term...Johnson
Aviation...Johnson/Nierenberg
Marine...Johnson/Nierenberg
Area Forecast Discussion
National Weather Service Charleston SC
1007 AM EDT Mon Oct 3 2016
.SYNOPSIS...
High pressure will build over the eastern United States through
tonight. Hurricane Matthew is expected to move north of the
Bahamas later this week and remain off the Southeast U.S. coast.
However, there remains considerable uncertainty in the strength and
track of the storm.
&&
.NEAR TERM /UNTIL 6 PM THIS EVENING/...
Moisture depth is slowly increasing across Southeast Georgia where
winds have been a bit more onshore for the past 12 hours or so.
This trend was captured well by latest set of RAP soundings. This
increased moisture combined with diurnal heating will support
isolated showers/tstms across mainly Southeast Georgia today with
the greater chances confined south of the I-16 corridor. Farther
north across Southeast Georgia, poorer moisture profiles and
lingering mid-level subsidence should keep that area dry. Adjusted
near term pops slightly with the late morning update. Highs in the
mid-upper 80s look reasonable.
&&
.SHORT TERM /6 PM THIS EVENING THROUGH THURSDAY/...
Tonight: As the high over New England begins to shift east, the
weak offshore coastal trough will drift toward the coast. This
will yield a slightly greater chance for showers along the entire
coast later tonight.
Tuesday through Thursday: High pressure will remain north of the
area while tropical cyclone Matthew moves north from near Cuba to
the Bahamas. Expect a general slow deterioration in conditions
through the period as Matthew draws closer to the area but there
still remains some uncertainty regarding the track/strength of the
storm which will impact how quickly and how much winds increase.
Nonetheless winds will increase, especially near the coast, as the
building high causes an increase in the pressure gradient. Also,
there will be some showers from time to time, mainly near the
coast.
&&
.LONG TERM /THURSDAY NIGHT THROUGH SUNDAY/...
Uncertainty continues higher than normal this period, although there
seems to be a bit more agreement amongst the 00Z/03 GFS and ECMWF in
a track a bit closer to the Southeast U.S. coast. For now we have
followed the latest NHC/WPC forecast which shows Matthew moving
north from the Bahamas through late week, remaining off the U.S.
East coast. Of course, impacts across southeast SC/GA will be
largely dependent on the track/intensity of Matthew and given the
forecast uncertainty we urge everyone to stay tuned to the latest
forecasts. At the very least we will likely see breezy/showery
conditions across the area, especially near the coast, until Matthew
moves northeast of the area.
&&
.AVIATION /14Z MONDAY THROUGH FRIDAY/...
VFR through tonight.
Extended Aviation Outlook: VFR conditions will generally prevail
through Tuesday outside brief showers and/or isolated thunderstorm
that shift onshore. Flight restrictions due to low clouds/showers
along with breezy/gusty winds are possible Wednesday through
Saturday, especially if tropical cyclone Matthew tracks close to the
Southeast U.S. coast.
&&
.MARINE...
Today: Expanding high pressure over New England and a weak
coastal trough along the SC/GA coast will result in increasing
northeast winds and building seas through tonight, though
conditions should remain below advisory levels.
Tuesday through Saturday: Winds will begin to increase Tuesday as
the pressure gradient tightens with high pressure building from
the north and tropical cyclone Matthew moving north toward the
Bahamas. Small Craft Advisory conditions will be possible starting
Tuesday, mainly beyond 20 nm. Later in the week conditions will
depend greatly on the track/strength of Matthew which is forecast
by the NHC/WPC to track north from the Bahamas while remaining
offshore the Southeast U.S. coast. However, considerable
uncertainty remains in the forecast at this time for mid to late
week so mariners should regularly check the latest forecast. As of
now, we think sustained tropical storm force winds could start as
early as Wednesday night, especially beyond 20 nm, and continue
through at least Friday night. Seas will also build significantly
Thursday night into Friday, possibly reaching at least 20 feet,
mainly beyond 20 nm.
Rip Currents: Increasing swell and stronger onshore winds this
afternoon warrant a moderate risk for the GA coastline. An enhanced
risk is expected mid to late week due to increasing winds/swells
associated with tropical cyclone Matthew.
&&
.TIDES/COASTAL FLOODING...
Tide levels are expected to increase into at least Friday or
until tropical cyclone Matthew moves north of the area. At this
time the storm is expected to remain offshore, so the risk of a
significant storm surge associated with a landfall is not likely.
However, tides could still get high enough to produce at least
minor saltwater inundation, especially along the SC coast, due to
the persistent strong northeast winds.
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...None.
SC...None.
MARINE...None.
&&
$$
Area Forecast Discussion
National Weather Service Dodge City KS
938 AM CDT MON OCT 3 2016
...UPDATE TO SYNOPSIS...
.SYNOPSIS...
Issued at 933 AM CDT Mon Oct 3 2016
WV imagery and 12Z upper air analysis indicate a slightly
negatively tilted upper level trough of low pressure shifting
slowly eastward across the Northern Rockies and the Great Basin
setting up an increasingly difluent southwest flow aloft across
the Western High Plains. Near the surface, a lee side trough of
low pressure is strengthening across eastern Colorado.
&&
.SHORT TERM...(Today and tonight)
Issued at 223 AM CDT Mon Oct 3 2016
Breezy conditions this morning will become windy in the afternoon
as mixing deepens and gusts increase to the 30 to 40 knots range.
This will be partially a result of deepening low pressure across
northeast Colorado through the day in response to the approaching
Pacific low pressure now diving though Nevada. Highs reaching the
mid 80s are expected this afternoon, with more mild lows again
tonight, ranging from mid 50s west to the mid 60s in the central
Kansas counties. Slight chances for shower and Thunderstorms will
be carried over through the overnight as an instability/moisture
axis works its way across the area. However the better chance for
convective initiation supporting severe storms appears more likely
on Tuesday afternoon, in the extreme eastern counties, as the
cold front moves across the area.
.LONG TERM...(Tuesday through Sunday)
Issued at 223 AM CDT Mon Oct 3 2016
Cooler conditions area are forecast following the cold front. A
secondary vort lobe rotates out of the west Wednesday night and
Thursday, reinforcing a cooler airmass for late in the week.
Temperatures may not exceed the 60s Friday, setting up a fall-
like weekend with highs in the 70s. In the meantime, cold dry air
will be in place late Thursday night. Lows aren`t forecast to
freeze, however mid to even low 30s are possible across west -
central Kansas.
&&
.AVIATION...(For the 12Z TAFS through 12Z Tuesday morning)
Issued at 615 AM CDT Mon Oct 3 2016
A trough of low pressure at the surface will deepen across
eastern Colorado as an upper level trough moves into the Central
Rockies. Southerly winds at 10 to 15 knots earlier this moring
will increase to around 25 knots by 18z Monday at DDC and GCK. 25
plus knot winds will be possible in the HYS area by 21z Monday.
VFR conditions are expected today and overnight given that the RAP
and NAM both indicate the cloud bases will be at or above 6000ft
AGL. There will also be a chance for thunderstorms overnight given
the mid level instability, moisture and lift. The better
opportunity for this convection will be between 00z and 03z
Tuesday at GCK, 03z and 06z Tuesday at DDC, and finally 06z to 12z
Tuesday at HYS.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 86 62 78 46 / 20 20 10 0
GCK 87 58 75 42 / 20 20 10 0
EHA 88 55 75 43 / 20 20 0 0
LBL 87 61 78 44 / 20 20 10 0
HYS 83 61 74 45 / 30 30 20 10
P28 82 65 80 53 / 20 50 40 20
&&
.DDC Watches/Warnings/Advisories...
NONE.
&&
$$
SYNOPSIS...JJohnson
SHORT TERM...Russell
LONG TERM...Russell
AVIATION...Burgert
AREA FORECAST DISCUSSION
National Weather Service Des Moines IA
631 AM CDT Mon Oct 3 2016
.SHORT TERM.../Today/
Issued at 339 AM CDT Mon Oct 3 2016
For the third consecutive day the primary forecast challenge is fog
trends during the early morning hours, with clearing and mild
weather expected thereafter. The large surface ridge that was draped
across Iowa last night has moved off to the east but not as far as
expected, resulting in continued very light winds across the
forecast area this morning. Fog initially developed in our
southeastern counties and has been slowly spreading northwest into
central Iowa. Low level flow trajectories and HRRR depictions
support a continuation of this trend, and it is likely that we will
again see a significant increase in fog coverage for a brief period
between about 11Z and 13Z. However, only two or three stations in
Iowa have reported quarter mile visibility to this point and given
the limited dense fog threat in time and space, no advisory is
anticipated. The expected expansion of fog just before sunrise may
be handled by special weather statements again if warranted.
.LONG TERM.../Tonight through Sunday/
Issued at 339 AM CDT Mon Oct 3 2016
No real changes to previous forecasts...active weather expected in
the extended with two major systems affecting the Central Plains
this upcoming week. Though tonight will be relatively quiet over
central Iowa...clouds will be on the increase from the system approaching
from the west. Subjective 00z H850 analysis last evening showed upstream
large scale trough and associated dual shortwaves over the Rockies
at this time. The leading wave over eastern Colorado is already
tapping into a broad zone of warm air advection and moisture from
western Texas northward to Nebraska. A warm front aloft is beginning
to create a shield of clouds over the high Plains...and these will
eventually move east into western Iowa overnight tonight as strong
warm air advection...height falls associated with leading wave and
vort max all aid lift overnight across Nebraska. The line of storms
expected to move east/northeast will weaken as it moves into Central
Iowa Tuesday morning...only to strengthen as a second and stronger
wave over the southern Plains drives northeast from the Texas
Panhandle to western Iowa by 00z Wednesday and western Wisconsin
by 12z Wednesday. This will help push a cool front across the
region overnight Tuesday night/Wednesday morning with convection
likely all night. Though the most robust convection is likely to
remain south of Iowa Tuesday afternoon and weaken somewhat as it
moves northeast overnight...some concerns remain. Both the Euro
and GFS forecast the strength of the low level jet to approach
50kts Tuesday evening...MUCAPE of 400-800 j/kg and a gradient of
0-3km SRH values of 300-400 m2/s2 somewhat ahead the leading edge
of the convective line as it enters western Iowa. There are some
slight differences in the timing of the upper level forcing versus
the lower level forcing which may reduce the overall threat of
severe weather. This high shear/low cape environment needs to be
watched for the potential of a tornado risk with the passing line
of storms. Currently the area is outlooked for a marginal risk of
severe storms Tuesday evening. PWATS are in the 1.5 inch range so
there will be the potential for brief heavy rainfall. Through at
least Tuesday and lingering into Wednesday highs will be generally
well above normal in the 70s. There continues a consistent signal
for a stronger shortwave...one off the Oregon coast at 18z Tuesday...
to rapidly strengthen and move into Iowa by Thursday afternoon.
Another but weaker shortwave will precede this Wednesday night
into Thursday morning. Several rounds of thunderstorms will be
likely from late Wednesday night into Thursday with elevated
convection likely Wednesday night and potentially surface based
convection over portions of southeast Iowa Thursday afternoon.
There is still considerably differences between the GFS and Euro
solutions on Thursday...though both indicate a strong signal for
thunderstorms and some severe potential. PWATS again approach 1.5
inches with this system so another round of potentially moderate
to briefly heavy rainfall may occur. Averages over the region this
week may range from 0.5 to nearly 2 inches. Will better define the
amounts closer to each event. Highs will be cooler on Thursday
with the exception of the southeast which may still be in the warm
sector. Otherwise...the weekend from Friday through Sunday more
fall like with seasonal highs and lows along with generally dry
weather. A weak upper level system may spread some clouds and a
few light showers across the region over the weekend...but with
uncertainty and a weak signal in the models will leave out of the
forecast for now.
&&
.AVIATION.../For the 12Z TAFS through 12Z Tuesday morning/
Issued at 631 AM CDT Mon Oct 3 2016
Once again areas of fog have developed early this morning and are
producing IFR or lower visibilities at DSM and FOD. Expect the fog
to dissipate rapidly between about 1230Z and 1400Z as it did
yesterday and the day before. Thereafter VFR conditions are
anticipated with quiet TAFs.
&&
.DMX WATCHES/WARNINGS/ADVISORIES...NONE.
&&
$$
SHORT TERM...Lee
LONG TERM...REV
AVIATION...Lee
Area Forecast Discussion
National Weather Service Quad Cities IA IL
946 AM CDT MON OCT 3 2016
.UPDATE...
Issued at 942 AM CDT Mon Oct 3 2016
Morning balloon data shows a strong inversion starting around
850mb that goes up to 825 mb. RAP trends indicate this inversion
will remain through the day. Winds below the inversion are under 7
mph which raises questions regarding cloud break up.
So, a fairly significant revision to the forecast has been done.
Cloud cover has been increased considerably and max temperatures
have been lowered. Those areas that are currently clear should see
diurnal cloud development by late morning that continues into the
afternoon.
A revised forecast reflecting these changes should be available in
about 15 minutes.
&&
.SYNOPSIS...
Issued at 325 AM CDT Mon Oct 3 2016
The latest sfc analysis was indicating a passing ridge center acrs
the northeastern DVN CWA and up acrs WI/MI U.P. attm, while
southeasterly return flow off to the west was tightening up the
reach of the plains. Aloft, upstream omega block ridge acrs the
plains and MO RVR Valley was adjusting eastward to the upper MS RVR
Valley, while a large upper wave was seen on the latest water vapor
loop digging southeastward acrs the GRT BSN. Back closer to home,
the IR fog loop was indicating stubborn stratocu deck hanging on
from LK MI southwestward into northeastern MO.
&&
.SHORT TERM...(Today and Tonight)
ISSUED AT 325 AM CDT Mon Oct 3 2016
Today...Will continue the fog watch early this morning in the clear
areas of the northwestern third or more of the CWA, as well as the
west central IL area if clear patches try to arrive out of central
IL. Otherwise the cloud deck is alleviating even a patchy fog threat.
The stratocu deck and cloud cover in general with it`s affects on
temps, will continue to be a challenge today. Flow in the cloud
bearing layer is projected to veer from the northeast to the
southeast as the morning and day progresses behind departing ridge
axis to the east. This veering flow pattern would look to slosh back
higher RH fields/stratocu acrs and southeast of the area today,
maintaining areas of clouds and in general mostly cloudy to partly
cloudy coverage. Several of the 00z run models indicate this with
mostly cloudy sky coverage for much of the day. But some concern for
areas that are currently clear like the northeastern half of the
forecast area, that as the sun gets up clouds may erode as they try
to move back. But they may also develop there own instability CU
fields and Cu rule values are at least broken coverage by late
morning even in the northwest. Thus will play it mostly to partly
cloudy for the flavor of the day. Will not put it in the forecast,
but diurnal light sprinkles will again be possible in lingering more
substantial cloud decks(southeastern half of the area) this morning
into early afternoon. With a few cloud breaks, will go widespread 70
or lower 70s...areas that stay mostly cloudy again will be held in
the mid to upper 60s, while other areas that get more hours of
insolation will warm toward the mid 70s.
Tonight...Will continue the idea of a mix of stratocu cloud decks
and patches of clear sky into the overnight acrs the local area.
Will also bank on enough of a southeast sfc wind of 5 to near 10 MPH
maintaining in tightening return flow gradient to temper much of
any fog threat late tonight. But if sfc winds drop below 4 MPH under
clear patches, there may be at least patchy fog again especially
east of the MS RVR. With the sfc wind and some lingering clouds in
mind, will go with lows in the mid to upper 50s CWA-wide. Otherwise
lighter winds and clear skies would translate into lows in the upper
40s to lower 50s again. ..12..
.LONG TERM...(Tuesday through next Sunday)
ISSUED AT 325 AM CDT Mon Oct 3 2016
All indications are trending toward an active mid to late week
period, featuring warmer than normal temperatures and periods of
thunderstorms, possibly strong, and the potential for at least
locally heavy rainfall. Cooler and drier weather follows for the
weekend as the slow moving boundary is replaced by high pressure.
Tuesday: Warm advection ahead of the upper trough and surface cold
front advancing from the plains will result in a breezy and warm
day, with highs in the mid to upper 70s. If cloud cover is thinner
than models are suggesting, temperatures could touch 80 in the
south. Tuesday night, 40 to 50 kt low level jet develops, spreading
elevated instability into the area by late evening for scattered
showers and thunderstorms in the west, increasing to likely toward
Wednesday morning as the weakening front moves into the forecast
area under an upper level shortwave in the cyclonic flow around the
upper low over southern Manitoba.
Wednesday: Have lowered pops during the day as the latest model runs
have a period of shortwave ridging and drying following the
overnight convection that exits to the northeast in the morning.
Temperatures will again be tied to cloud cover and the location of
the stalling surface boundary over the region. For now have highs
back into the lower 70s north to upper 70s south. Things could get
interesting Wed evening, as the next shortwave in the SW upper level
flow approaches with the stalled boundary over the region. Low level
shear profiles and upper level divergence may be favorable for
possible strong to severe storms. Instability, however, may be more
of a key factor as MUCAPES appear on the marginal side. SPC has a
marginal risk on day 3, over much of the forecast area based on
these features. As models continue to vary from run to run,
confidence in these details is low, but will continue to monitor
this development.
Thursday into Thursday night is looking increasingly like a wet
period under the SW flow aloft with models now showing Gulf moisture
and PW values possibly as high as 1.5 getting entrained into the
southerly flow feeding into the forecast area. This could result in
widespread rainfall of a half to possibly an inch or more, depending
on the timing and track of a wave of low pressure most models have
passing along the slow moving boundary over the area from SW to NE.
The Canadian and European models dry things out for Friday, while
the GFS depicts an upper trough passing through the area that would
keep rain chances going possibly into Saturday. For now, the blended
approach results in low pops hanging on Friday into Friday night
with temperatures only climbing into the 60s, after the several day
stretch of 70s.
High pressure eventually spreads into the area over the weekend with
its cooler, drier airmass limiting highs to the 60s. Lows could
possibly dip into the 30s in some areas Saturday night if the colder
near zero C 850 mb temperatures of the GFS pan out.
&&
.AVIATION...(For the 12Z TAFS through 12Z Tuesday Morning)
ISSUED AT 701 AM CDT Mon Oct 3 2016
After areas of IFR to LIFR fog(mainly in the VCNTY of CID and DBQ)
diminish after 9 AM, A stratocu deck of mainly VFR levels will
continue linger acrs most of the TAF sites for much of the day.
Light southeast sfc winds of 4-8 KTS today and tonight, becoming
5-10 KTS west of the MS RVR late tonight in increasing sfc pressure
gradient from the west. Will bank on this overnight sfc wind
maintaining enough, along with lingering VFR stratocu deck to
prevent more areas of IFR to LIFR fog from developing late tonight
into early Tue morning. ..12..
&&
.DVN Watches/Warnings/Advisories...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
UPDATE...08
SYNOPSIS...12
SHORT TERM...12
LONG TERM...Sheets
AVIATION...12
Area Forecast Discussion
National Weather Service Grand Forks ND
940 AM CDT Mon Oct 3 2016
.UPDATE...
Issued at 940 AM CDT Mon Oct 3 2016
Adjusted POPs for current radar trends. Strongest cells in the
northern counties have mostly moved off into Canada, but some
weaker convection just to the south should skirt by western Benson
and Towner counties during the next few hours, so kept POPs going
for a bit longer. Otherwise thinks look good for another warm but
windy day over the rest of the CWA.
UPDATE Issued at 640 AM CDT Mon Oct 3 2016
The thunderstorm cells that were hovering over Grand Forks earlier
have now lifted NE and have weakened. Meanwhile, another area of
storms intensified near Rugby. These are also moving NE and should
lift into southern Canada by mid morning. Have added some pcpn
chances to this area until then.
&&
.SHORT TERM...(Today and tonight)
Issued at 359 AM CDT Mon Oct 3 2016
The main forecast challenge will be pcpn chances, starting with
what is going on early this morning. Since midnight, a cluster of
tstms has been lifting northeast through the Grand Forks area.
This seems to be associated with low level warm advection and the
low level jet. The HRRR lingers this activity in the northern Red
River Valley up toward the northwest angle of MN into mid Monday
morning, before it lifts into southern Canada. Then the rest of
the day should be dry, with the attention shifting to increasing
wind speeds. A pretty healthy 850mb jet develops through the late
morning, but mainly for areas west of the FA. Not expecting
advisory criteria wind speeds, but just below, so it will be a
windy afternoon along and west of the Red River Valley. Not a lot
of drop off in the thermal fields today, and with the gusty south
winds expected, going to go on the higher side of guidance for
highs today. This would have highs fairly similar to yesterday, or
areas in the southern FA close to 80F again. The 850mb jet cranks
up even more tonight, helping to spread more moisture and pcpn
northward into the FA. Despite this, pcpn amounts on the models
are on the lighter side tonight.
.LONG TERM...(Tuesday through Sunday)
Issued at 359 AM CDT Mon Oct 3 2016
Still looks gusty into Tuesday, as the sfc low lifts into
southeast Saskatchewan. This will push the steadier pcpn into MN
during the day. There is a ribbon of instability associated with
this, but at this point the stronger values stay south of the FA.
Therefore pcpn amounts still look fairly light. This changes
somewhat by Tuesday night as the low level jet cranks up again.
Most models show one to two inches of rain up into the eastern FA,
from Wadena to Bemidji. As the sfc low tracks across Manitoba
and on northeast Wed into Wed night, winds turn west then
northwest and stay on the gusty side. There may be a little light
pcpn up along the Canadian border, but most models look dry.
Thursday to Monday will provide a roller coaster of temperatures as
the period starts off below normal for the end of the week before
rebounding to above normal for the start of next week. Upper level
trough will slowly propagate across the Northern Plains thursday and
Friday with 850mb temps falling into the 0 to minus 5C range. This
will bring the first round of widespread freezing temps so far this
fall on Friday and or Saturday morning. Clouds and winds still to
have an impact in the timing and details, nonetheless the airmass
will be very cool compared with recent weather as highs struggle to
near 50F on Friday. Temps do begin to moderate on Saturday some with
50s expected to turn to mid 60s by next Monday. Mostly dry weather
is expected with a few showers possible Saturday.
&&
.AVIATION...(For the 12Z TAFS through 12Z Tuesday morning)
Issued at 640 AM CDT Mon Oct 3 2016
Main aviation issue will be increasing wind speeds today, as it
looks particularly windy by mid afternoon into the evening. May
lose some of the gusts after sundown, but sustained winds will
remain high. Other challenge is thunder development tonight. Have
gone with a late evening or overnight VCTS to cover the potential
for now, and later shifts can refine as needed.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...None.
MN...None.
&&
$$
UPDATE...JR
SHORT TERM...Godon
LONG TERM...Godon/JK
AVIATION...Godon
Area Forecast Discussion...UPDATED
National Weather Service Chicago/Romeoville, IL
1054 AM CDT Mon Oct 3 2016
.UPDATE...
1050 AM CDT
As suspected by the overnight shift, clouds have been and will
remain slow to clear south of I-90 this afternoon. Aircraft
sounding data out of MDW indicates the cloud depth is only
800-1200 ft thick, however the cloud bearing flow is very light.
In fact, this flow begins to turn southeast this afternoon,
potentially expanding the clouds northward back over the Rockford
area. Do expect there to be some afternoon holes to develop,
probably most likely near the current edges, with areas along the
I-80 corridor the last to see any sun, and possibly not seeing at
all. The RAP 850mb RH captures conditions well and seems to have a
good forecast based on forecaster analysis, so this model field
has been used to nudge the sky cover forecast into this evening.
Have made minor adjustments to temperatures which already well
accounted for the clouds. Will have to further assess to see if
some scattering/thinning happens into overnight, potential
increasing a fog threat.
MTF
&&
.SHORT TERM...
333 AM CDT
Through tonight...
First concern out the gate this morning, and the only real
concerns for today and tomorrow, are some patchy dense fog, and
resolving cloud cover and impact on temperatures.
Most areas finally get to say good riddance to the upper low that
plagued the region over the last 5 days or so. Earlier there was
some drizzle in cloudy areas and light rain over and downwind of
the lake as weak energy continues to swing southward on the back
side of the low. Otherwise we are seeing little in the way of
erosion of the cloud deck which is laid out W-E across much of the
area as we get a continued NE 925-850 flow off the lake. High
surface pressure is resulting in a weak wind field, rain/drizzle
earlier today coupled with no significant drying behind the low
has maintained low dewpoint depressions, and this has manifested
patchy/areas of dense fog both south and north of the cloud
shield, and is not allowing the cloud shield to erode.
The surface high will slowly shift east to Lake Michigan today,
resulting in an onshore flow pattern. Upper ridging across the
plains will shift overhead, and the low-mid level wind field will
be in a transition from N to S today, which would suggest some
warming to the airmass, but with a fairly light wind regime and
with the shifting winds, wherever the clouds are they may linger
through the day. We will likely see some erosion but guidance
suggests enough moisture and low level lapse rates that support
the stratocumulus field filling back in. Where we see some
clearing low 70s are likely, with upper 60s elsewhere.
Deep column south-southwesterly flow will set up for Tuesday.
Expect a little better clearing though will have some higher
clouds around. Expect temps will head back above normal, easily
into the 70s. SE surface flow will limit moisture advection and
should feel pretty nice.
KMD
&&
.LONG TERM...
333 AM CDT
Tuesday through Sunday...
Warm and occasionally unsettled conditions will give way to seasonally
cool conditions this weekend.
The upper low will move to the Canadian prairies Tuesday night into
Wednesday, which will allow deeper moisture to approach. The
system`s dynamics head largely north with the dry slot intrusion
moving through the upper Midwest. There will likely be a complex
of showers and thunderstorms to our west Tuesday night. With the
low level jet ramping up considerably, there could be a shower
locally Wednesday morning, but low coverage. MUCAPE is weak on
soundings and therefore isolated thunder would be expected, even
with the strong low level jet as lapse rates are not great. Have
some precip chances in the afternoon though forcing is somewhat
benign and limited instability. Above normal highs in the mid 70s
to around 80 south are expected.
Additional energy off the Pacific coast will dig into the mean western
trough Wednesday night. Shortwaves and moisture advection will
move into a lingering surface boundary across the middle
Mississippi valley, just to our southwest. Precipitation chances
increase during late Wednesday night into Thursday morning period
as a result. A high PWAT airmass in place at this time suggests a
concern for heavy rainfall producing showers and storms, somewhat
hinging on the boundary locations as the upper forcing is not
clear later Wednesday/Wednesday night. A strongly sheared
environment will exist overnight, but at this point coverage looks
to remain highest Wednesday night to our west. Warm conditions
continue on Thursday as the warm front lifts north during the
daytime, likely accompanied by showers or some storms. Readings
will likely be reach the 70s north to again near 80 south
depending on cloud cover.
A sharp inverted trough to our west will likely keep precipitation
chances elevated later Thursday/Thursday night ahead of the
system`s cold front. Model guidance still not in great agreement
regarding how much upper level energy will be in place with the
cold front, which is set to move through Friday or Friday evening.
Ensemble agreement is also somewhat low, keeping confidence on the
extent and amount of showers and storms Friday/Friday night low as
well. High pressure will build over the upper Great Lakes Saturday
which will give us another glancing blow of seasonally cooler air
and somewhat breezy conditions as Hurricane Matthew moves along
the Atlantic seaboard.
KMD
&&
.AVIATION...
For the 12Z TAFs...
Cloud cover has hang on across the area, and this kept the fog
from developing over the area. Aside for some fog potential at
KRFD in the next couple hours, the fog threat has ended across the
area. However, there could still be a short period of some MVFR
CIGS this morning, but otherwise VFR conditions are expected by
this afternoon. Surface high pressure over the area should
continue to result in light winds today, which will become
easterly through the day.
KJB
&&
.MARINE...
220 AM CDT
Light northerly winds today are expected to shift south-
southeasterly tonight into Tuesday in response to a potent storm
system taking shape across the Northern High Plains. This storm
system will shift northward into southern Manitoba by Wednesday,
then shift towards Hudson Bay later in the week. During this
period high pressure over New England will help produce a
strengthening pressure gradient over the Great Lakes. As a
result, southerly winds are expected to increase up to 25 to 30 KT
by Wednesday. Although the strongest of these winds will be over
central and northern sections of the lake, offshore gusty winds
could result in gusts of 20 to 25 KT in the southern Lake Michigan
near shore waters. As a result, small craft conditions are
possible Wednesday.
A cold front will approach the western Lakes region Wednesday
night and likely weaken and become nearly stationary for a period
into Thursday. During this period, it appears that another
significant upper level disturbance will induce the development of
another surface area of low pressure over the Central Plains
states. This low may then quickly track northeastward along the
remnant cold front later in the week. This storm system may then
produce another period of strong southerly winds and
thunderstorms over the lake Thursday night into Friday, followed
by a period of northerly winds into the weekend.
KJB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...NONE.
IN...NONE.
LM...NONE.
&&
$$
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Area Forecast Discussion
National Weather Service Marquette MI
739 AM EDT Mon Oct 3 2016
.SHORT TERM...(Today and tonight)
Issued at 450 AM EDT MON OCT 3 2016
Water vapor imagery and RAP analysis show that the mid level low
that was centered near Detroit 24hrs ago has weakened and is now
over Lake Ontario. A deep trof has moved over the western CONUS, and
downstream of this feature, a ridge extends from the southern Plains
to northern Ontario. This ridge and the associated sfc high pres
centered over se Hudson Bay and ridging ssw across the Upper Lakes
are providing a tranquil early morning across the fcst area. With
clear skies and calm winds, temps have fallen down into the 30s at
the traditional cold spots. Some fog has also developed and has been
most persistent and more widespread over far western Upper MI.
Otherwise, up to this point, fog that has developed across the area
appears to be patchy/shallow as suggested by widely varying vis at
some obs locations and by satellite imagery which does not show much
indication of fog other than over far western Upper MI. To the ne, a
large are of stratus has advanced sw across northern Ontario to the
n and ne shoreline of Lake Superior.
Since fog is mostly patchy/shallow, expect the fog to burn off
during the morning hrs. Models indicate that low level winds should
veer sufficiently to the e and se quickly enough this morning so
that the stratus advancing toward northern and eastern Lake Superior
should begin to be pushed w and then nw before reaching the fcst
area. Still, will be something to monitor during the morning. The
developing e to se wind may bring some low clouds off Lake MI into
the far south central fcst area later today. Otherwise, it appears
abundant sunshine should mostly prevail. Fcst soundings suggest max
temps generally in the upper 60s to around 70F, a nice early Oct
day.
Tonight, s to se low-level winds will increase as sfc high pres
ridge shifts e and pres gradient tightens. Given the abundant low-
level moisture present over Lower MI into northern IN/IL and the
additional moisture that will be picked up off the relatively warm
Lake MI waters, expect low clouds/fog to develop tonight as this
warmer/moister air upslopes into the cooler conditions over Upper
MI. Fog should be most widespread and become denser over the central
fcst area, roughly in the area bounded by Crystal Falls, Ishpeming,
Escanaba and Menominee where upsloping will be most pronounced.
Nearly every model is generating light pcpn in this area late
tonight. Given the fairly shallow sfc based moisture layer, any pcpn
that occurs should be -DZ, and fcst will reflect this idea in the
area mentioned above where upsloping is strongest.
.LONG TERM...(Tuesday through Sunday)
Issued at 412 AM EDT MON OCT 3 2016
A warm, moist sly flow ahead of an aprchg cold fnt wl result in a
good deal of lo clds on Tue along with some fog/drizzle especially
over the scentral in the mrng. A shrtwv/sfc lo pres lifting ne fm
the Plains into scentral Canada wl drag a weak cold fnt acrs the Upr
Lks on Wed, accompanied by a band of showers. Although there wl be a
brief drying trend on Wed ngt behind the fropa, another disturbance/
lo pres lifting newd within the larger sw flow alf btwn a rdg over
the se CONUS and troffing over the w wl bring another round of
showers later on Thu into Fri. Temps wl remain above normal into
Fri. The arrival of cooler air behind the lo pres could cause some
lk effect showers late Fri into Sat before hi pres blds into the
area later in the weekend and causes a drying trend.
Tue/Tue ngt...Upr MI wl be dominated by a steady/gusty sly flow with
h925 winds incrsg to 40 kts under tight pres gradient btwn sfc hi
pres over New England/the Cndn Maritimes and a deep lo pres moving
newd fm the nrn Plains into Manitoba ahead of a vigorous shrtwv
lifting out of a deep upr trof over the wrn CONUS. As this sly flow
taps incrsly moist llvl air under a subsidence invrn just blo h85,
expect a good deal of lo clds away fm the downslope areas near Lk
Sup. With upslope flow off Lk MI, maintained fog fcst on Tue mrng
and added some patchy drizzle over the scentral where a number of
the models show some lgt qpf. But mid lvl dry air associated with
slowly departing upr rdg dominating ern NAmerica wl prevent more
substantial pcpn until at least late Tue ngt, when the warm conveyor
belt mstr ribbon/axis of pwat aprchg 1.50 inches ahead of cold fnt
attendant to lo pres moving thru Manitoba wl drift into the far wrn
cwa. Temps wl be well above normal as h85 temps over the far w are
fcst as hi as 12C within the strong sly flow.
Wed...Shrtwv/lo pres over Manitoba are fcst to continue to the ne
into far nw Ontario and aprchg Hudson Bay by 12Z Thu. The attendant
cold fnt/warm conveyor belt mstr ribbon/axis of deep lyr qvector
cnvgc wl cross the Upr Lks on Wed accompanied by a band of showers/
perhaps a TS. Even though pwat near 1.50 inches wl be 200-250 pct of
normal, passage of the stronger shrtwv well to the nw and quick
moving fnt/warm conveyor belt wl limit pcpn totals. Vigorous deep
lyr drying/deep lyr qvector dvgc in the wake of the fropa wl end the
pcpn and even allow a return of some sunshine by late in the day
over the w. Since the airmass following the fropa wl be Pacific in
origon under a sw flow aloft btwn the lingering wrn trof and the
persistent upr rdg over the se CONUS, temps wl remain above normal.
Wed ngt...Weak rdg of hi pres/mid lvl drying air following the fropa
wl bring a period of dry wx. But with h85 temps falling no lower
than about 8C and a steady wsw wind, temps wl remain above normal
despite expected clr-pcldy skies.
Thu into Fri...Lo pres is fcst to dvlp on Wed ngt over the central
Plains as a disturbance over the srn Rockies within the wrn trof
begins to lift to the ne. Except for the 00Z GFS, medium range
guidance had come into fairly good agreement showing the shrtwv/sfc
lo pres moving to the ne, reaching the Upr Midwest on Thu and
crossing Upr MI Thu ngt before exiting into Ontario on Fri. The 00Z
GFS on the other hand shows the shrtwv and a weaker lo pres aprchg
fm the sw and then exiting to the ne at a slower pace. Since this
new GFS run is quite different fm previous runs as well as the most
recent GFS ensemble fcst, suspect the 00Z Cndn/12Z ECWMF models are
on the right track. Those fcsts would sug a period of likely pops
beginning late Thu until the early mrng hrs on Fri for at least a
portion of the cwa would be warranted as the vigorous dynamic
forcing interacts with pwat fcst as hi as 1.50 inches. After the lo
shifts to the n on Fri, cooler air wrapping into the area could
cause some lk effect showers under the cyc nw flow left in the wake
of the departing lo pres, especially over the nw cwa, depending on
the degree of llvl drying.
Extended...Some lk effect showers, that could be mixed with some sn
at least over the hier terrain, wl be psbl especially over the hier
terrain of the nw cwa into Sat as h85 temps fall toward -3 to -5C in
the cyc wnw flow left in the wake of the lo pres exiting thru
Ontario. Right now, it appears sfc temps in the areas that would be
impacted by the lake effect showers wl be too warm to include a
specific mention of snow showers attm. Hi pres aprchg fm the nw in
the wake of the exiting shrtwv/sfc lo pres under rising hgts should
bring a drying trend for Sun/Mon. Temps at the start of the weekend
wl be near normal, but readings should return above normal early
next week under the sw flow left in the wake of the passing hi pres
rdg.
&&
.AVIATION...(For the 12Z TAFS through 12Z Tuesday morning)
Issued at 739 AM EDT MON OCT 3 2016
Some fog/MVFR conditions may affect KIWD/KSAW for the next hr.
Otherwise, VFR conditions will prevail into the evening at
KIWD/KCMX/KSAW. Increasing sse winds tonight will transport low
level moisture back into the area. Combined with upslope flow off
Lake Michigan, expect KSAW to eventually fall to LIFR late in the
night. With more of a downslope component to the wind at KIWD/KCMX,
VFR conditions will probably prevail thru the end of the fcst
period at those 2 terminals.
&&
.MARINE...(For the 4 AM Lake Superior forecast issuance)
Issued at 450 AM EDT MON OCT 3 2016
Winds today will be mostly under 15kt with sfc high pres ridge over
the Upper Lakes. As this ridge shifts e and a cold front advances
across the Plains, SE to S winds will gradually increase tonight
thru Wed. Winds will become strongest over central and eastern Lake
Superior, reaching the 20-30kt range Tue night into Wed. The cold
front will pass across Lake Superior Wed aftn/evening. While W to SW
winds up to 15-25kt should occur behind the front Wed night into Thu
morning, strongest between Isle Royale and the Keweenaw Peninsula,
pres gradient and winds will weaken for a time Thu aftn/evening as a
low pres trof develops over the Upper Lakes ahead of a low pres wave
developing over the southern Plains. After this low pres wave passes
Thu night, NW winds up to 20-25kt will develop on Fri.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
None.
Lake Michigan...
None.
&&
$$
SHORT TERM...Rolfson
LONG TERM...KC
AVIATION...Rolfson
MARINE...Rolfson
Area Forecast Discussion
National Weather Service Norman OK
628 AM CDT MON OCT 3 2016
.DISCUSSION...
12Z Aviation.
&&
.AVIATION...
South winds will increase across the area, especially the west
today. There will be some chances of storms moving into western
Oklahoma from the west after midnight tonight. Otherwise, VFR
conditions are expected.
&&
.PREV DISCUSSION... /issued 432 AM CDT MON OCT 3 2016/
DISCUSSION...
Current convection is staying north of the 37th parallel and
drifting northeast. the rap hints at some showers possible in the
west early this morning, but it is the outlier and will not put
POPs in for this morning at this time.
Higher storm chances are expected to develop late tonight. The
models (especially the ECMWF) have been a little less aggressive
with the overnight development, but still expected to see
scattered storms developing. As the upper trough approaches on
Tuesday, the vort max is well timed to support storm development
tomorrow afternoon. Forecast instability and shear will be
sufficient to produce some severe storms, although there still are
a couple of questions about how strong of a severe storm
potential. First is low-level moisture quality. Winds are still
blowing offshore along the Texas Gulf coast this morning, although
mid-upper 60s dewpoints are lurking along the coast. Low level
southerly flow will increase today and tonight advecting the
better moisture north, but the higher dewpoints may still be a
late arrival. The second question is what affects morning
convection will play on the surface pattern and the developing
instability, but with models hinting at less-widespread convection
in the morning, this may be less of an issue. Agree with SPC`s
enhanced risk of severe storms across the west for Tuesday
afternoon and evening.
The trends in the models also now indicate more of a separation in
time between the first trough moving through over the plains
Tuesday and the approach on Thursday night/Friday of the next
trough that develops in the western U.S. With this timing, the
storms with the first wave will move out Tuesday night or early
Wednesday morning, with storm chances redeveloping Wednesday
afternoon and becoming more widespread Thursday and Thursday night
with the approach of the second trough. But these models have also
been changing the scenario over time, so we will see how it plays
out.
&&
.PRELIMINARY POINT TEMPS/POPS...
Oklahoma City OK 82 65 83 64 / 10 10 40 40
Hobart OK 84 65 84 58 / 0 30 40 20
Wichita Falls TX 85 66 87 66 / 0 20 30 20
Gage OK 83 64 85 49 / 10 30 20 10
Ponca City OK 84 65 84 61 / 10 20 50 50
Durant OK 85 61 86 68 / 0 0 10 30
&&
.OUN Watches/Warnings/Advisories...
OK...None.
TX...None.
&&
$$
Area Forecast Discussion
National Weather Service Sacramento CA
901 AM PDT MON OCT 3 2016
.SYNOPSIS...
Mostly cloudy skies with scattered light showers today. A return
to drier and milder weather begins Tuesday.
&&
.DISCUSSION...
No major changes to forecast this morning. Will probably tweak the
forecast rain for this afternoon and evening and lower the
amounts. Current observations and radar imagery showing that
showers are fairly light this morning. Guidance from the CA-NV
River Forecast Center was lower this morning for NorCal and the
HRRR also indicates that minimal rain will impact our region today.
These light showers will linger through the morning into
afternoon. By tonight, expect showers to diminsh so that much of
our CWA is drier by Tuesday. Warming trend still on track for the
rest of this week. JBB
.Previous Discussion...Upper trough is shifting east through the
Great Basin into the Rockies and remaining showers have ended in
the northern Sierra. Northwest flow on the backside of the trough
covers NorCal, and satellite imagery shows plenty of cloudiness
upstream moving our way.
Scattered light showers will be possible across interior NorCal
today as the offshore moisture plume reaches the coast. TPW of
around an inch is forecast to reach the coast around the Bay Area
by midday, but large scale lift will be minimal resulting in only
spotty light precipitation.
Precipitation chances retreat to far northern California near the
Oregon border for Tuesday into Thursday as ridging from the
eastern Pacific moves into NorCal. Temperatures will return closer
to seasonal averages by Thursday.
&&
.EXTENDED DISCUSSION (Friday THROUGH Monday)
An upper level high pressure ridge will keep dry weather and
seasonally average temperatures across northern California Friday
and Saturday. Highs in the valley are expected to be in the upper
70s to mid 80s, and 50s/60s in the higher elevations.
Model forecast solutions begin to differ on Sunday to a track of
a shortwave upper level trough. General agreement is to a stormy
pattern at the moment, but amplitude and timing of the feature is
inconsistent. There could be a chance for the depicted wave to be
the next weather making system that could bring some chances for
precipitation. However until the track is determined, it is
unknown at this time whether or not rain chances will be greatest
for the Pacific northwest or further south into California. As per
model consensus, decided to go with a more dry solution at this
time until better model agreement can be determined.
&&
.AVIATION...
VFR conditions are expected for the valley terminals during the
next 24 hours. Some chances for showers in the vicinity for the
northern Sacramento valley today. Broken to overcast middle and
high clouds will be present across northern California with MVFR
to IFR ceilings and visibilities for some portions of the Sierra,
especially during light rain and snow showers that are possible
again today for the higher elevations.
&&
.STO Watches/Warnings/Advisories...
None.
&&
$$
Area Forecast Discussion
National Weather Service Bismarck ND
309 PM CDT Mon Oct 3 2016
.SHORT TERM...(This evening through Tuesday)
Issued at 121 PM CDT Mon Oct 3 2016
A severe thunderstorm threat highlights the short term period.
A negatively tilted upper level trough will lift northeast from
the central rockies into the northern high plains this
afternoon/evening and into southeast Montana tonight. This results
in cyclogenesis along the northern and central high plains and a
surface low lifting into southeast Montana this evening.
The latest iterations of short term models have become more
impressive with the low level shear over southwest into west
central ND from mid afternoon into this evening. 17 UTC iteration
of the RAP indicates the Significant tornado parameter and 0-1km
helicity maximized from 22-24 UTC Today over west central ND,
combined with low LCL values. High shear and low LCL values
continue into northwest and north central ND but surface heating
will be limited compared to the southwest/west central. The
thunderstorm threat also diminishes as you move east into south
central ND with the decrease in forcing associated with the strong
upper trough.
In addition to the severe threat this afternoon and evening, the
NAEFS ensemble situational awareness table is showing a strong
southerly transport of moisture into the region with an all time
maximum of precipitable water compared to climatology, over the
far northwest and north central. With the fast movement expected
with this dynamic system...will not issue any flood highlights
but will pass along. Heavy rain will be more of a threat as you
move into the deformation area over northwest and north central
ND.
After this evening...large dry slot swings across the area
bringing an end to the precipitation tonight
.LONG TERM...(Tuesday night through Monday)
Issued at 121 PM CDT Mon Oct 3 2016
Winds and rain or snow showers Tuesday through Wednesday then
Freezing temperatures highlight the long term forecast.
On Tuesday the surface and upper lows lift northward through
western ND and eastern MT with a significant dry slot over most of
the forecast area. There may be a little lingering showers early
Tuesday from the turtle mountains area into the James River
Valley. Then by the afternoon the wrap around moisture associated
with the upper low works its way into western Nd. This moisture
remains confined to mainly northwest ND Tuesday night. There is
enough cold air wrapping around the system to perhaps change
precipitation over to snow over the northwest late Tuesday night.
as the upper low tracks east...there may be a period of light snow
or rain and snow along the northern tier counties Wednesday
morning. The low finally exits the area late Wednesday bringing an
end to any light precipitation. If we do see any snow Tuesday
night through Wednesday, at this time it does not look like
anything more than a mix of rain and snow to a light dusting.
Wednesday night through Friday night will bring a stretch of
mainly dry but much colder weather. For the most part daytime
highs will be in the 40s and 50s with overnight lows in the mid
20s to mid 30s. We anticipate Freeze headline over the west
Wednesday night into Thursday morning. Then across most if not all
of western and central ND Thursday night and again Friday night. A
hard freeze will likely be experienced by most by the end of the
upcoming weekend. No highlights at this time but will continue a
mention within the HWO.
&&
.AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon)
Issued at 121 PM CDT Mon Oct 3 2016
Scattered showers and thunderstorms will continue across western
and north central ND this afternoon, including KDIK KISN and KMOT.
These will eventually move into south central ND tonight. Brought
a mention of showers and thunderstorms with temporary MVFR cigs
all taf sites as the precipitation swings through the state. MVFR
ceilings move into western and then central ND Later tonight into
Tuesday morning with the wrap around moisture.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...TWH
LONG TERM...TWH
AVIATION...TWH
Area Forecast Discussion
National Weather Service Quad Cities IA IL
330 PM CDT MON OCT 3 2016
.SYNOPSIS...
Issued at 308 PM CDT Mon Oct 3 2016
18Z surface data has high pressure from the Great Lakes to the Gulf
Coast while a storm system was organizing in the Rockies. Dew points
were in the 50s from the Great Lakes and Plain with 60s in the lower
Mississippi Valley.
&&
.SHORT TERM...(This Evening through Tuesday)
ISSUED AT 308 PM CDT Mon Oct 3 2016
Dry conditions expected from late this afternoon through Tuesday.
The persistent inversion aloft is keeping the clouds in place across
the area. RAP trends indicate clouds should remain in place for much
of the area tonight. The exception appears to be the northwest third
of the area which may see the diurnal clouds break up after sunset.
Some patchy fog may or may not develop late tonight where skies
briefly clear.
Gradually increasing flow aloft should help break up the clouds
starting late Tuesday morning and continuing through the afternoon.
How long the clouds remain in place will half an impact on
temperatures. However, it does appear that Tuesday will be warmer.
.LONG TERM...(Tuesday Night through Monday)
ISSUED AT 330 PM CDT Mon Oct 3 2016
Main forecast concern for the long term are the chances for rain and
thunderstorms starting tomorrow night through part of the day
Friday. A series of trofs will affect the area leading to multiple
rounds of showers and thunderstorms. Some of these storms could be
strong to severe, especially on Wednesday and Thursday. The SPC has
the area in a marginal risk of severe weather Wednesday and a 15%
risk across the far south on Thursday.
At the beginning of the long term the guidance suggests convection
will be ongoing across western Iowa. These showers and storms will
slowly progress to the east through the overnight hours as the wave
moves east. A warm front will try to lift through the area. Deep
layer shear is close to 50 kts across the area. The bulk of this
shear exists in the lowest 0-3km layer, where values of 35 to 40 kts
are forecast. While storms should be coming in with the lowest
instability, these strong shear values suggest a HSLC environment.
This will need to be monitored for potential wind and tornado
threat. The NCAR 3-km ensemble suggests the potential for rotating
storms across western IA during the afternoon and evening.
Wednesday, have continued with drier forecast with ridging moving
into the area. Latest guidance suggest MCS development that will
run across the CWA overnight. This MCS will be contingent on where
the front is across the area. With this detail tied to mesoscale
phenomena, the forecastability of this MCS location remains low. If
this MCS occurs across our area, there may be residual OFBs that
could affect Thursday`s severe weather potential.
Thursday, the main wave moves across the CWA, bringing with it a low
and the renewed threat for severe weather. Current guidance pulls
the low and warm front north of the area. This may be difficult if
an MCS forms the night before. Regardless, shear and instability
parameters suggest possible strong to severe storms again. It is
imperative to note that these threats are completely contingent on
what occurs the day before as the mesoscale features will dictate
what happens.
After this, high pressure moves into the area and suggests a quiet
weekend. Models diverge in solutions for next week, so confidence
is low in the current forecast.
&&
.AVIATION...(For the 18Z TAFS through 18Z Tuesday Afternoon)
ISSUED AT 1225 PM CDT Mon Oct 3 2016
VFR conditions with cloud cigs around 4 kft agl will be seen
through 18z/04. The possibility does exist that areas of MVFR or
even IFR conditions may develop 06z-12z/04 if breaks develop in
the clouds.
&&
.DVN Watches/Warnings/Advisories...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
SYNOPSIS...08
SHORT TERM...08
LONG TERM...Gibbs
AVIATION...08
Area Forecast Discussion
National Weather Service Grand Forks ND
311 PM CDT Mon Oct 3 2016
.SHORT TERM...(This evening through Tuesday)
Issued at 311 PM CDT Mon Oct 3 2016
Precipitation timing and strength will be the primary headaches
for the period.
The upper low currently over WY will lift north and eastward
towawrds western ND tonight and tomorrow. The surface low will
come up along the MT/ND border tonight, keeping southeasterly
winds over our CWA that will remain fairly breezy. With the
increasing clouds and good mixing from the winds, lows tonight
will be very warm for the season, staying in the 50s to low 60s.
A few of the short range models have a preliminary round of
showers and storms moving into the western CWA this evening,
although the HRRR and RAP have been backing off on this idea and
are drier. The global models are evenly split between those
bringing in precip this evening and the later solutions. Given the
current track of convection over western ND is nearly due north,
think the best chances will be later tonight as the low pressure
system gets a bit closer and 850mb warm air advection picks up.
Have some low POPs in the far western tier this evening for any
stray showers out ahead of the main system, but think the main
show will be after midnight. There is some weak elevated CAPE so
kept thunder mention going.
Tomorrow, the surface trough axis and a cold front will move into
the CWA as the low center wraps up to our northwest. The models
show signs of the first round of activity in the morning fizzling
out and redevelopment across the MN counties by afternoon as the
frontal boundary approaches. Going forecast had highest POPs in
our east Tuesday afternoon and this seems to fit the latest runs.
Depending how much destabilization we get ahead of the afternoon
development, some storms could become strong to severe and a
marginal risk now includes our southeastern counties. NAM
currently has CAPE values around 500 J/kg or less, but with deep
bulk shear up around 40 to 50 kts by Tuesday evening stronger
cells are possible.
.LONG TERM...(Tuesday night through Monday)
Issued at 311 PM CDT Mon Oct 3 2016
Wednesday through Thursday...Still looks like a dry slot situation
will develop later Tue night as stacked low hangs way back over
NW North Dakota. Some def zone pcpn is possible during part of
Wednesday as the low structure moves toward Winnipeg. Best area
for this round of pcpn will be along a tract well north of US 2 .
Attention will then shift to the much cooler air mass diving in
behind this system evidenced in part by subzero 850 mb temps
showing up the far west forecast area early Thursday morning. Not
showing any pops for the day on Thursday, although patchy to areas
of frost should start showing up during the morning over the
Devils Lake basin.
Friday through Monday...Minimal if any pcpn is likely for the Friday
through Monday time interval. More widespread frost certainly
likely Friday and Saturday morning with freeze risks increasing as
surface temps drop to near 32 over a substantial portion of the
region. Chilly highs mostly in the 40s on Friday will moderate
only a couple of degrees on Saturday. Manitoba high pressure
should drift to Minnesota late Sunday setting up weak return flow
and milder temps by late afternoon. Stronger warm air advection
Monday lofting 850 mb levels into double digits above zero would
be reflected at surface with highs in the 60s.
&&
.AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon)
Issued at 1234 PM CDT Mon Oct 3 2016
VFR conditions at all TAF sites with breezy south to southeast
winds gusting into the 20 to 30 kt range. The winds will continue
to be fairly breezy overnight, although there will be some
reduction in gusts. Some VFR ceilings as some cirrus and then mid
level clouds come in from the west overnight. MVFR ceilings will
arrive late in the period tomorrow morning as precip starts to
move into the forecast area. Have VCSH starting at KDVL shortly
after 12Z with the rest of the TAF sites later in the morning as
the precipitation pushes east. Some thunder is not out of the
question due to weak instability, but think that it will be fairly
isolated so just kept VCSH for now. South to southeast winds with
gusts above 20 kts will continue into Tuesday morning.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...None.
MN...None.
&&
$$
SHORT TERM...JR
LONG TERM...WJB
AVIATION...JR
Area Forecast Discussion
National Weather Service Pueblo CO
314 PM MDT Mon Oct 3 2016
.SHORT TERM...(This evening through Tuesday)
Issued at 314 PM MDT Mon Oct 3 2016
Upper low lifting into WY this afternoon with band of strong low/mid
level winds rotating eastward across CO. Have seen gusts of 40-50
mph over much of the region, with some 50-60 mph gusts at usually
wind-prone areas such as Walsenburg and Alamosa. RH has tanked and
Red Flag Warning is verifying over most of the I-25 corridor and
plains, with critical conditions persisting for few more hours into
the evening. Some concern about rather erratic wind direction in the
vicinity of the Beulah Hill fire, as obs and latest HRRR suggest
some sort of weak eddy in the lee of the Wet Mountains the next few
hours, though predominate wind direction will be SW, taking any
smoke toward Pueblo. Left some low pops in place for a few showers
along the continental divide this evening, with low chances for tsra
near the KS border through about 02z, as dewpoints have yet to mix
out over the extreme east. Winds die out overnight, with a shift to
N-NW flow along and east of the mountains as weak cold front drops
south through the plains. Cooler conditions with less wind expected
on Tue under wly flow aloft, though winds will likely become gusty
in spots after 18z, as rather deep dry air mass promotes efficient
mixing.
.LONG TERM...(Tuesday night through Monday)
Issued at 314 PM MDT Mon Oct 3 2016
Tuesday night through Thursday...Brisk westerly flow aloft across
the region will become more southwesterly on Wed as a broad upper
trough digs across the Great Basin and Rockies. GFS and EC models
bring showers back into western CO by Wed evening, then across all
of the forecast area Thu. A cold front is expected to drop down
across the Palmer DVD late Wed night, increasing pcpn showers for
the I-25 corridor Thu aftn and eve, as well as cooling temps
significantly. Max temps are forecast to warm into the 70s to near
80 F for the plains Wed, with 60s for the high valleys. On Thu temps
are only expected to climb into the 60s for the e plains, and 50s
for the high valleys. Showers should come to an end by late Thu
night as the upper trough exits to the east.
Friday through Monday...A ridge of high pressure will sit over the
desert sw, with an embedded disturbance bringing some isolated
showers to the southern portions of the forecast area Sun night and
Mon. Otherwise dry conditions with gradually warming temps are
expected, with the potential for max temps above 80 F for the plains
once again by Sun. Moore
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 314 PM MDT Mon Oct 3 2016
VFR conditions at all TAF sites tonight and Tuesday, though may need
to watch KPUB this evening, as smoke from the Beulah Hill fire could
drop vis into the 3-5sm range at times until sunset. Strong S-SW
winds, with gusts to 35-45 kts, will persist at all terminals into
the evening, before diminishing overnight. Lighter westerly flow
expected on Tuesday.
&&
.PUB WATCHES/WARNINGS/ADVISORIES...
Red Flag Warning until 7 PM MDT this evening for COZ226>235.
&&
$$
SHORT TERM...PETERSEN
LONG TERM...MOORE
AVIATION...PETERSEN
Area Forecast Discussion
National Weather Service Reno NV
229 PM PDT Mon Oct 3 2016
.SYNOPSIS...
Below average temperatures will continue through Thursday with
cool northwest flow aloft. A couple weak waves will move through
bringing the threat of light showers mainly north of I-80 tonight
and again Wednesday. Overnight lows will moderate somewhat
tonight, but widespread freezing temperatures are possible once
again from Wednesday through Friday mornings. A warming trend is
expected this weekend as high pressure builds over Nevada.
&&
.SHORT TERM...
A few changes made to the short term, but the overall ideas remain
the same. A dirty northwest flow aloft will continue into Thursday
with a couple short waves moving through. The first is currently
moving through with a few light showers, snow above 6500-7000 feet
or so. Most of these will diminish this evening and overnight so
kept any chance of precip north of I-80. The models look very weak
with the forcing and the HRRR continues to show any showers
weakening as they move in.
A bit of a break in the precip chances for Tuesday and Tuesday
night as most of the deeper moisture remains in Oregon. A slight
chance of showers remains near the border there, but otherwise
dry. Temperatures will remain cool, but we should see a few
degrees of warming, especially with more sun tomorrow compared to
today. Tuesday night could be quite cold, and the models are
trending toward lighter winds and less cloud cover. With this in
place, temperatures may drop lower than forecast so lowered the
temps in many Western NV valleys. I contemplated issuing a freeze
watch for Western NV as we have not had a widespread freeze yet,
but didn`t as my confidence is rather low.
Wednesday, another wave moves through with the best chance of
showers again north of Susanville-Gerlach with snow levels
6500-7000 feet. Temperatures will be similar to Tuesday with
similar temps aloft. Thursday morning could be another cold
morning if the skies clear behind the wave. The cool air gets
reinforced with that wave, but it will just keep the status quo
going with temps Thursday.
.LONG TERM...Friday through Monday...
A modest upper ridge will reside over northeast California and
western Nevada Friday through Saturday night. This will bring
seasonable temperatures and mainly light winds, with periodic high
clouds possible.
Next Sunday and Monday, discrepancies arise with a piece of upper
level energy approaching the Pacific Coast. GFS simulations weaken
the low and bring it in as an elongated trough axis while the ECMWF
drops the low south off the California coast, missing the region
entirely. However, while simulations vary with the behavior of the
low/trough axis, any disturbance looks weak so it may not make too
much difference outside of some temperature uncertainty and cloud
cover (so no major forecast concerns).
Briefly looking beyond the 7-day period, simulations/ensembles show
the northeast Pacific becoming more active as a large-scale trough
and strong jet stream invade that region. While this is not likely
to impact eastern California and western Nevada immediately, it is
possible that chances for precipitation will increase around the
middle of the month as models and the Climate Prediction Center
expect the trough to edge closer to the Pacific Coast. Snyder
&&
.AVIATION...
Weak forcing/warm air advection is bringing a few light snow showers
to the eastern Sierra above about 7000 feet MSL this afternoon. The main
impact for that area will be some higher terrain obscuration. Farther
north to the Oregon border, decks are lower with MVFR CIGS in -SHRA
(-SHSN above 5500-6000 ft MSL). Elsewhere across western NV and
eastern Mono County, VFR conditions prevail with SCT-BKN decks in
the 110-140 MSL range.
Showers should taper off this evening, with just some residual VFR
decks persisting generally north of I-80.
Tuesday, a weak disturbance will slide across far northern CA and NV
in the afternoon. This will mainly just bring some mid level clouds,
although a few -SHRA north of a KSVE-KWMC line are possible. Winds
aloft could increase enough with the impulse to bring some turbulence
downwind of the northern Sierra. Snyder
&&
.REV Watches/Warnings/Advisories...
NV...None.
CA...None.
&&
$$
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