Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 11/29/16
Area Forecast Discussion
National Weather Service Albany NY
1011 PM EST Mon Nov 28 2016
.SYNOPSIS...
An active period of weather for the region as a couple of storms
are set to impact the region. While most of the precipitation will
fall as rain, a period of wintry type weather is expected from the
Mohawk Valley and southern Adirondacks east to southern Vermont
and the Berkshires overnight into early Tuesday morning. In the
wake of these storm systems, brisk and cooler weather is expected
for the end of this week.
&&
.NEAR TERM /UNTIL 8 AM TUESDAY MORNING/...
A Freezing Rain Advisory has been issued for the Southern
Adirondacks...Mohawk Valley...Lake George Saratoga
Region...Southern Vermont and the Berkshires from 3 AM until 8 AM
Tuesday morning.
As of 1015 PM EST...Skies have been slow to cloud over this
evening and as a result temperatures have fallen quickly. With
readings now in the mid 20s to mid 30s across much of the region
and likely to remain in this range for much of the night before
rising late tonight...have issued a Freezing Rain Advisory as pcpn
likely to start in that form when it starts later tonight.
A deep cyclone over the center of the nation remains quasi-
stationary with an impressive plume of moisture racing from Baja
California into the mid and lower Mississippi River Valley. The
low level jet increases quickly toward sunrise close to 50kts with
strong isentropic lift and impressive omega signatures. Question
is just how low temperatures will get before the cloud coverage
arrives and temperatures slowly moderate as the precipitation
arrives. At this time, low level ageostrophic flow per the latest
RAP remains and increases in magnitudes from the northeast.
Otherwise, clouds increase and PoPs increase from southwest to
northeast well after midnight.
&&
.SHORT TERM /8 AM TUESDAY MORNING THROUGH WEDNESDAY NIGHT/...
Impressive low level jet along with warm/moist advection will be
across the region through most of the day. So a rainy and breezy
day (mainly across the terrain) setting up across the region. As
is the case in these low level jet warm advection regimes, its
difficult to mix down the higher momentum air aloft. A possible
exception would be portions of the Taconics, Berkshires and
Catskills. Winds may back just enough to result in a bit more
magnitudes for these areas as we will continue to watch if those
backing of the winds materializes. South to southeast winds of 10
to 20 mph with some gusts in the 30-40 mph are possible. The 12Z
GEFS remains with southerly wind anomalies /+v-component/ of 1 to
3 standard deviations above normal with PWAT anomalies a couple
standard deviations above normal in the late morning into the
early pm. In addition, did include the slight chance mention of
thunder along the I84 corridor which is in coordination from SPC
and OKX. The showalter values drop close to +1C and per lightning
activity upstream, showalter values of +2C and lower is where
lightning activity was most prevalent. Highs Tuesday climb mainly
into the 40s with some lower 50s south of the Capital District.
Tuesday Night...A lull in the action is expected as a micro-
ridge or bubble-sfc high, but it will be short-lived as another
short-wave will be ejecting along the E/SE flank of the H500
positively tilted long-wave trough from the Southeast and TN
Valley. As a few breaks in the clouds are expected and very moist
low levels, fog could be an issue as we will add patchy fog to the
forecast/grids. The clouds will thicken again overnight from the
south and west towards sunrise. Lows will be on the mild side with
mid 30s to mid 40s.
Wed-Wed night....More rain on the way. Deep transport of moisture
from the Gulf of Mexico, as low pressure approaches from the Ohio
Valley during the morning. Strong/Impressive isentropic lift
increases ahead of the cyclone and warm front again. PWATS surge
back to 2-3 standard deviations above normal. In the area of upper
level diffluence aloft, expect periods of moderate to heavy rain
to overspread the region by the afternoon into the evening period,
especially along the enhanced FGEN band expected to lift northward
across the region. Likely to categorical pops were used again
through Wednesday into the early evening hours. An additional
two-thirds to around 1.25 inches of rainfall is expected and well
coordinated. These rain amounts should help out the drought
conditions across the region (see hydro section for additional
details). Above normal temps are likely in the mild air mass with
mid 40s to mid 50s again...and lows mid and upper 40s south and
east of the Capital Region...and mid 30s to lower 40s from Capital
District north and west.
Triple point per the NCEP model suite and ECMWF is expected to
move across the mid-Hudson Valley into northwest CT Wednesday
evening. There could be another brief period of thunder potential
for the southern portions of the region which we may add in future
forecast updates. Precipitation should taper back from southwest
to northeast as dry slot advances quickly into the region. Once
again, southeast low level jet may enhance wind gusts into the
Catskills, Taconics and Berkshires and southern Greens early
Wednesday evening.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
The long term period starts out with a departing surface low off the
New England coast. A second low over eastern Canada will be
responsible for some wrap around moisture across the northern
mountains on Thursday along with some lake enhanced pcpn downwind of
Lake Ontario. The remainder of the forecast area should be dry.
Highs on Thursday will be in the Upper 30s to lower 50s.
Thursday night through Friday night...Another weak clipper system
moves across southern Canada bringing more light pcpn to the region
with some lake enhanced pcpn continuing downwind of Lake Ontario
through Friday. Lows Thursday night are expected to range from the
upper 20s to mid 30s with highs on Friday in the mid 30s to upper
40s and lows Friday night in the mid 20s to lower 30s.
Saturday through Sunday...A mainly dry forecast is expected as high
pressure ridges into the region. There still may be a little lake
effect activity into northern Herkimer county but that should be the
extent of it. Highs on Saturday and Sunday will be in the upper 20s
to mid 40s with lows Saturday night mainly in the 20s.
&&
.AVIATION /03Z TUESDAY THROUGH SATURDAY/...
VFR conditions with sct high level cirrus clouds expected through
the evening hours as high pressure moves east of the region.
Clouds will thicken overnight and ceilings will gradually lower
after midnight.
Expect VFR conditions to persist until around 12Z tomorrow, with
light rain beginning between 09Z-12Z. Light to moderate rain
during the morning combined with a moist southeast flow off the
Atlantic Ocean should allow for IFR ceilings and visibilities by
mid morning with some LIFR ceilings and visibilities from late
morning into the afternoon.
Surface winds will be variable around 5 kt or less through 12Z
tomorrow before increasing from the southeast to 5 to 10 kts with
gusts to 20kts later in the morning at KALB.
Outlook...
Tuesday Night: Low Operational Impact. Slight Chance of SHRA...FG.
Wednesday: High Operational Impact. Likely RA.
Wednesday Night: High Operational Impact. Breezy Definite SHRA...RA.
Thursday: Slight Chance of SHRA.
Thursday Night: No Operational Impact. NO SIG WX.
Friday: Low Operational Impact. Slight Chance of SHRA.
Friday Night: No Operational Impact. NO SIG WX.
Saturday: No Operational Impact. NO SIG WX.
&&
.FIRE WEATHER...
Wet conditions will prevail through the middle of the week.
&&
.HYDROLOGY...
No widespread hydro problems are expected the next 5-7 days
ending Friday.
Diurnal snow melt will continue over the higher terrain through
the mid week period. A widespread rainfall along with milder
temperatures are expected Tuesday into Thursday with a series of
disturbances impacting the region.
The first round of rainfall with a brief light mix of sleet snow
and ice north of the Mohawk Valley and Capital Region occurs
Tuesday morning, then all rain by late morning. Rainfall amounts
of a third of an inch to three quarters of an inch are expected
with up to one inch south of Albany.
The second round of rain comes late Wednesday morning into
Thursday. Total rainfall may be three quarters of an inch to an
inch and a quarter. The runoff from the rainfall combined with
some higher elevation snowmelt may cause some elevated flows, but
a widespread flood potential is not expected at this time.
It has been quite dry in past months but vegetation and trees are not
soaking up water this time of year. MMEFS and latest NERFC
outlooks suggests no problems at this time but some areas just
west of our area are showing the potential to perhaps get solidly
into action stage (mainly southern tier of NY). Overall, the rain
should help the drought conditions across the ALY HSA.
For details on specific area rivers and lakes, including observed
and forecast river stages and lake elevations, please visit the
Advanced Hydrologic Prediction Service /AHPS/ graphs on our
website.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...Freezing Rain Advisory from 3 AM to 8 AM EST Tuesday for
NYZ032-033-038>043-048>050-082>084.
MA...Freezing Rain Advisory from 3 AM to 8 AM EST Tuesday for
MAZ001-025.
VT...Freezing Rain Advisory from 3 AM to 8 AM EST Tuesday for
VTZ013>015.
&&
$$
SYNOPSIS...BGM
NEAR TERM...BGM/11
SHORT TERM...BGM
LONG TERM...JPV
AVIATION...SND/11
FIRE WEATHER...BGM/Wasula
HYDROLOGY...BGM/Wasula
Area Forecast Discussion
National Weather Service Binghamton NY
953 PM EST Mon Nov 28 2016
.SYNOPSIS...
A storm system will spread rain showers and mild temperatures into
NY and PA late tonight and Tuesday. A second storm system will
ride up the east coast on Wednesday, bringing another round of
rain.
&&
.NEAR TERM /THROUGH TUESDAY/...
945 PM Update...
Slowed down the arrival of precip to mainly after 06Z now, based
on the slow progression of rain to our west. Temps into the 40s
from I-81 west, and even upper 30s just east of I-81. Across
extreme northeast Otsego County, far eastern Delaware, and extreme
eastern Sullivan counties, temps are between 30 and 32. Some of
the higher resolution model guidance (RAP13) and even blended
shorter term guidance have a good handle on the overall situation
depicting these colder areas well. This guidance shows temps
rising between now and the arrival of the precipitation, as our
cloud cover lowers and thickens. Temps in these areas seem to
have bottomed out and are currently steady. Just west of these
sites mesonet obs across southwest Herkimer county, along the
border with Otsego have risen 2 to 4 degrees in the past 2 hours
and are now above freezing. Given the above we will continue to
keep all rain in the forecast overnight with no mention of ice.
The previous AFD is below...
555 PM Update...
The timing of rain tonight looks good and so do our minimum temps.
The latest RUC has the 850 MB 0C line up across northeast, well
removed from our area. Despite some cooling in the mid levels
thanks to evaporational cooling, strong warm air advection
tonight will be enough to keep the precip all in the liquid form.
We only had a few tenths of snow in the far east but that is the
only minor change I made, removing it from our forecast. The
previous AFD is below.
210 PM update...
A large storm system spinning over Minnesota and Wisconsin will
pull moisture into NY and PA this evening. The model trend
continues to point toward slower solutions, and our current
forecast does not bring precipitation into our far western
counties until after 2z.
The slower solution also means the low stratus won`t reach our FA
until late, so minimums will be a tad lower than previously
forecast. Temperatures are forecast to rise after 6z.
With slightly cooler temperatures entrenched over the east, it is
possible the front edge of the precipitation will contain a wet
snow-rain mix, especially east of I-81. No more than a tenth of an
inch of snow accumulation is anticipated.
Precipitation will exit the I-81 corridor during the late-morning
or early-afternoon hours. Temperatures will max out in the lower
or middle 50s Tuesday.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/...
Main concerns in the short term remain focused around the potential
for fog Tue night and Wed morning...the next batch of rain expected
during the day Wednesday...and lingering light rain showers Wed
night through the day Thursday.
Exiting system to the east will leave in its wake a weak area of
high pressure along with a brief period of ridging aloft to help
keep conditions relatively dry Tue night and Wed morning. The
potential for rain will be low during this time, but the threat for
fog will increase under this largely suppressed and nearly saturated
air mass. With the recent rain Tuesday over much of the area and waa
aloft, conditions will be favorable for patchy fog through early
Wednesday.
The ridge will be amplifying in response to a deepening trough of
low pressure cutting through the Great Lakes. There will also be
another robust supply of deep layer moisture advecting nwd along the
east coast ahead of this system, which will supply the necessary
ingredients for widespread rain, with locally heavy rain possible
from the Poconos into the srn Catskills. Large-scale dynamics
combined with a relatively strong baroclinic zone along the trailing
cold front will provide the lift needed to produce rain across the
region. PWATs close to 1 inch in ne PA will increase the potential
for around 1-2 inches of rain in this area. Locations further to the
west and north will likely see around 0.5 to 1 inch through Wed
night.
Upper low to the north will remain nearly stationary, or slow
moving, from srn Ontario into Quebec on Thursday. This upper level
support combined with weak caa in the mid levels, the potential
for scattered rain showers will exist through the day.
Morning low temperatures Wed will bottom out in the mid 40s.
Afternoon highs on Wed will rise comfortably into the mid and upper
50s. Low 40s expected again Wed night, with not much warming during
the day Thur...only into the mid and upper 40s.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
The extended period will remain quite active Thur night through
the weekend with high pressure over the deep south and a series of
upper waves tracking ewd through the Great Lakes into the NE under
a cool air mass regime. These waves will interact weakly with Lake
Ontario to produce periodic daytime/lower elevation rain showers,
and high elevation rain and/or snow showers. The showers will
likely become all snow by late Saturday and Sunday as the colder
air mass arrives.
Lows Thursday night will fall into the lower/mid 30s, and rise into
the upper 30s and lower 40s Friday afternoon. A bit colder Friday
night into the upper 20s/lower 30s. Temps will remain fairly steady
into the weekend with highs in the upper 30s and lows in the upper
20s.
&&
.AVIATION /03Z TUESDAY THROUGH SATURDAY/...
Rain will move into the terminals late tonight and move out around
midday Tuesday. The rain may start under VFR conditions then
quickly drop into the alternate required/IFR category beginning
around 10Z. Once the rain ends around midday the ceilings will
remain in the MVFR/alternate required category possibly IFR at
KBGM.
Low level wind shear is expected from around 09Z-18Z due to a
southerly low level jet around 40 knots at 2k feet. Surface winds
E/SE around 8-12 knots becoming 10-15 knots with gusts around 20
knots after 06Z then southwest Tuesday afternoon at 5-10 knots.
OUTLOOK...
Tuesday night-Thursday...Restrictions expected from periods of
rain.
Friday/Saturday...Restrictions possible in rain/snow showers.
&&
.BGM WATCHES/WARNINGS/ADVISORIES...
PA...None.
NY...None.
&&
$$
SYNOPSIS...DJP
NEAR TERM...DJP/Heden
SHORT TERM...BJT
LONG TERM...BJT
AVIATION...RRM
Area Forecast Discussion...UPDATED
National Weather Service BROWNSVILLE TX
526 PM CST Mon Nov 28 2016
.DISCUSSION...Updated for latest aviation discussion below.
&&
.AVIATION...Below average confidence still for dense fog at the
TAF sites, though MVFR after midnight and tempo IFR look pretty
good and were included in the TAFs. A frontal boundary is moving
into the Ranchlands and Brush Country with lower dew points, but
the HRRR for example doesn`t quite bring it through.
&&
.PREV DISCUSSION... /issued 253 PM CST Mon Nov 28 2016/
SHORT TERM (Tonight through Tuesday Night):
Base of upper trough moving
across NC Texas with the strong LLJ getting shunted eastward. This
shows up nicely on local doppler radar with veering winds gradually
spreading west to east through the morning. The associated cold
front, moving through the Hill country and into SC Texas, is
expected to slow down and pull up stationary over the CWA later
tonight. This will set the stage for fog development after midnight
as light SE winds usher in very shallow but high dew point air.
Models are a bit indifferent if there will be a low stratus deck or
the potential of dense fog. The favored areas will be across the Mid
and Lower Valley in the vicinity of the anticipated stalled front.
Models also show the worse conditions around and shortly after
sunrise when saturation reaches its peak. Confidence is slight below
average to issued a dense fog advisory at this time with model
uncertainty. With the front passing through approximately half of
the CWA temperatures will cooler across the NW Zones with another
much above normal night in the SE half.
The next upstream shortwave tracks across Texas later Tuesday with a
stronger cold front moving through the CWA Tuesday night. A non
eventful day is on tap with mostly cloudy to cloudy skies in the
morning with partial clearing in the east later in the afternoon as
low level moisture is shown to increase. the front is not expected
to bring rain with depth of the moisture remain below 850mb.
However, some streamer showers may develop over the Coastal waters
tomorrow night with a few possibly moving into the Lower Valley.
Otherwise, another warm day is in store with temperatures ranging in
the mid 80 to upper 80s and a few locals reaching 90 degrees in the
Mid Valley if the sun breaks out in time.
LONG TERM (Wednesday through Monday):
Beginning of the long term starts with the passage of the finale
of the cold front passage Wednesday morning. Still looks like
precipitation will be limited to mainly offshore waters. Dry air
sweeps in fairly quickly during the afternoon, so skies should be
nearly clear by sunset. This will provide for good radiational
cooling Wednesday night, with lows either side of 50 degrees. Weak
onshore flow returns on Thursday, slowly building cloud cover from
the coast inland.
The weekend forecast is still muddled by a considerable upper low
dropping into northwest Mexico. Most models are fairly consistent
with the low stalling across northwest Mexico most of the weekend,
with hints that it finally ejects starting Monday. This setup will
induce coastal troughing just offshore from south Texas for the
weekend, which produces a good overrunning pattern. Friday and
Saturday, all models are in good agreement on widespread
light rainfall for the region. Now the outlier model is the EC,
which depicts the cutoff low not really cutting off and quickly
jumping into the central US by Sunday. This would bring the
moisture to an end early and leave a drier Sunday and Monday. As
this seems to be the outlier of the remaining models, have opted
to discount the EC model, in favor of a blend of the remaining
models, which keep moisture and rainfall in the region through
Monday. With this in mind, have pushed PoP chances back up to low
end likely through Monday, before tapering off for Tuesday as the
cutoff low finally ends.
MARINE:
Now through Tuesday Night: South winds and the high seas will
continue to lower tonight as a cold front approaches the coastal
bend but residual higher seas may linger until between 9 pm and
midnight maintaining SCA`s offshore. the front pulls up stationary
and will be waiting for a reinforcing high pressure to push it
through around late Tuesday night or by sunrise Wednesday. In
advance of the wind shift expect a moderate southeast flow with a
moderate sea maybe high enough to warrant exercise caution
conditions. Small craft advisories are likely to be issued for the
early Wednesday cold front passage.
Wednesday through Friday: Winds behind the front Wednesday morning
will jump quickly to 20 to 25 knots, while seas jump to 8 to 10
feet with higher swells late in the afternoon. Conditions will
relax fairly quickly Wednesday night with onshore flow returning
Thursday morning. The coastal trough will develop by Friday
morning, with agitated conditions forecast through much of the
weekend. Seas will jump up to 9 to 12 feet for the weekend, with
winds onshore of 20 to 25 knots.
&&
.BRO WATCHES/WARNINGS/ADVISORIES...
TX...None.
GM...Small Craft Advisory until midnight CST tonight for GMZ170-175.
Small Craft Advisory until 9 PM CST this evening for GMZ150-155.
&&
$$
This product is also available on the web at:
HTTP://WEATHER.GOV/RGV
54/58
Area Forecast Discussion
National Weather Service State College PA
1052 PM EST Mon Nov 28 2016
.SYNOPSIS...
A broad storm system centered over the upper plains and midwest
will push a cold front through the commonwealth on Tuesday. A
widespread rain will fall late tonight and Tuesday. A second cold
front will follow for midweek. More rain and mild temperatures
will occur before cooler air and lake effect snow showers return
for the end of the week.
&&
.NEAR TERM /UNTIL 7 AM TUESDAY MORNING/...
A plume of deep Gulf of Mexico moisture in advance of potent
shortwave is supporting an expansive area of rain late this
evening from the Grt Lks south thru the Ohio Valley. Regional
radar loop at 03Z shows leading edge of the rain over Eastern
Ohio and HRRR indicates the rain will overspread Central Pa after
midnight. Best forcing from shortwave is progged to track west of
Pa, so expect the area of rain to diminish as it moves into
Central Pa late tonight. Steady or slowly rising temperatures
anticipated overnight under thickening cloud cover and WAA.
Inversion noted in model soundings should keep the wind from
becoming too strong/gusty in the central and eastern counties.
However, model soundings support gusts of 25-30kts across the
higher terrain of the Alleghenies.
&&
.SHORT TERM /7 AM TUESDAY MORNING THROUGH TUESDAY NIGHT/...
Low level jet and associated area of rain should have exited the
NW Mtns by dawn. However, a second, shortwave lifting northeast
from the Ohio Valley is expected link up with plume of +2-3SD
PWATS to produce a second batch of heavier rainfall across
southeast Pa between 12Z-18Z. Latest model guidance indicates the rain
could linger into late afternoon across Lancaster Co, but a
general drying trend from west to east is anticipated during the
late AM and afternoon. Model-blended QPF between tonight and
Tuesday ranges from a quarter inch or less across Mckean/Potter
Counties, to near 1 inch across the Lower Susq Valley.
Expect some breaks in the cloud cover by late in the day across
the Laurel Highlands per latest Superblend. However, 00Z NAM and
latest RAP suggest cold air damming and low cigs may persist
elsewhere until early evening. Thus, have lowered max temps
several degrees across the Central Mtns.
It may then be a dismal/damp but mild night Tues night. A wave
develops along the old front over the Deep South while another
front spins off-east of the midwestern storm center. Will keep
chc-low likely pops in for the very last part of Tues night in the
west.
&&
.LONG TERM /WEDNESDAY THROUGH MONDAY/...
Another significant wave forming on a trailing cold front will
ride up the west side of the appalachians and spread another slug
of rain up over the area by early Wednesday. Heaviest rain looks
to be over the SW through midday then shift to the SE in the
afternoon (along axis of highest PWAT air) where a period of
moderate rain is likely.
By late week, the upper low that had been hanging out over the
western Great Lakes morphs eastward across southern Canada,
ushering in a prolonged period of cold NW flow aloft and breezy
conditions at the surface - starting with a shortwave rotating
around the base of the low on Thu. The airmass doesn`t look
especially cold (fairly close to seasonal normals), but the cold
air flowing over the still quite warm lakes will be enough to
provide an extended period of widespread cloudiness and frequent
lake effect snow showers over the the NW mountains down into the
Laurel Highlands, possibly lasting all weekend long as the pattern
becomes slowly less amplified.
Much divergence in model solutions for early next week brings a
low confidence forecast during this period. The GFS is suggesting
a cold frontal passage while the ECMWF shows a very amplified
pattern. Went mainly away from the EC, but did include chance for
precip Sun night into Mon.
Temps peak Wed with highs back up into the 50s/lower 60s. Thu
will be a transition day back to colder temps with late
week/weekend just a shade below normal.
&&
.AVIATION /04Z TUESDAY THROUGH SATURDAY/...
Warm front lifting out of the Ohio Valley will cross central PA
tonight through early Tuesday. Expect lowering CIGs overnight into
tomorrow with a 6-to-9 hour period of rain beginning shortly
after 06z in the west and around 10z in the east. In addition, a
core of strong southerly winds aloft will accompany the rain. The
combination of these winds off the surface and relatively light
wind at ground level will yield widespread LLWS conditions.
Restrictions in the form of low CIGS are expected from about 07z-
18z in many locations, though these could very well linger into
late day over the east as a secondary wave likely keeps precip
going there. Vsby restrictions will also develop overnight, but
will be of shorter duration. LIFR is possible behind the rain in
the low CIGs over the N on Tues aftn/eve.
A brief break in pcpn should occur until the next front moves in
on Wed. Much colder air and prolonged NW flow will follow the
second front.
Outlook...
Tue...Low cigs/rain, mainly in the morning W and all day in the SE.
Wed...Rain/low cigs possible.
Thu-Sat...Sct SHSN w/ocnl IFR in BFD-JST. Isold SHSN AOO-UNV-
IPT. VFR Elsewhere.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
Synopsis...Dangelo
Near Term...Fitzgerald
Short Term...Dangelo/Fitzgerald
Long Term...RXR
Aviation...RXR
Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
935 PM EST Mon Nov 28 2016
.UPDATE...
Forecast remains on track. Updated to refresh wording as the lead
edge of the main precipitation activity is now lifting into the
cwa. Nose of incredible low level jet, 60 knots on KDTX vad at 4.0
kft agl and 65 knots on KIWX vad at 4.0 kft agl, is now lifting
northward into the state from the south. Nam forecast has
925-850mb winds of 65 knots at 03Z just south of Toledo. As a
result, expecting top end ageostrophic response at exit region of
low level jet. Already seeing east to west orientated fine line
structures emanating due northward; gravity wave packets symptomatic
of the mass adjustment. Best of forcing appears tied to the anchor
point to the anticyclonic bifurcation of this low level jet axis
that is now near Indianapolis; forecasted to track towards far
western shoreline of Lake Erie. With a leaf like orientation of
the Z echoes to the north of this point still expecting some
isolated, brief heavy rainfall potential from 4-6Z for the south
half of the cwa. All observational evidence suggests a very
stable layer in place between 900-2000 ft agl, but will be
monitoring winds at the surface this evening with the low level
jet in close proximity.
&&
.PREV DISCUSSION...
Issued at 704 PM EST Mon Nov 28 2016
AVIATION...
Residual dry air in the lowest 5000 ft has proven stubborn very late
this afternoon as many locations have been holding with VFR cigs.
This is an artifact of southeastern Michigan`s proximity to the far
eastern edge of the massive warm conveyor. With upstream
observations already IFR just west of the cwa, expectations are for
IFR cig and vsby restrictions very quickly after the start of the
TAF period.
The main precipitation activity is immediately south of the cwa
at press time with regional Z mosaic showing moderate rainfall now
surging northward across portions of northern Indiana and western
Ohio. This precipitation is supported by high-end dynamics
including: stout, direct Differential Cyclonic Vorticity
Advection, strong compact area of 10000-500mb geopotential height
falls, and very efficient upper level divergence and anticyclonic
flow trajectories aloft. The convection and instability balance
appears maximized sufficiently...per upstream Z echo structure
(fineline and striations) over eastern IL and western IN that the
potential for brief heavy rainfall may exist. Timing of this
activity, if it were to in fact continue, would be around
southeastern Michigan at approximately 4-5Z. Otherwise, it is
this rain shield and moisture content that is expected to result
in the widespread IFR to potential LIFR conditions and bring the
bulk of the rainfall amounts.
Inherited mention of non convective LLWS remains good. Latest Vad
wind from KDTX has 50 knots down to 3000 ft agl.
For DTW...Widespread IFR conditions to possibly LIFR will overspread
DTW within the first few hours of the period. Widespread moderate
with some potential for isolated heavy rain to impact the terminal
until roughly 09Z tonight. Drizzle potential will then exist through
daybreak. Cold front passage is timed at DTW around 14Z with a minor
change in wind direction from about 190 to 210. VFR cigs to develop
by mid morning with return to MVFR likely Tuesday evening.
//DTW Threshold Probabilities...
* High for ceilings AOB 5000 feet into Tuesday morning.
* Low for thunderstorms affecting terminal this evening (00-06z)
PREV DISCUSSION...
Issued at 311 PM EST Mon Nov 28 2016
DISCUSSION...
Lead batch of showers with initial moisture surge this morning
shriveled up and dissipated, as there was a lot of dry air in the
low levels to overcome, as 12z dtx sounding checked in with a 44 C
dew pt depression at 850 mb. Plenty of moisture over the Western
Ohio Valley however, as ILX sounding indicated a 7 C dew pt at 850
mb. Should be no problem to generate widespread showers this
evening/tonight as upper wave/cold pool (-26 C at 500 mb) ejecting
out of the southern Plains will slide into Southern Lower Michigan
by morning. Excellent dynamics/negatively tilted trough axis,
coupled with modest instability (sfc-850 MB going slightly negative)
supports isolated mention of thunderstorms, as thunderstorms have
also been reported upstream over Illinois, although the steep
level lapse rate (8 C/KM) arrive toward 12z, and that is
associated with the mid level dry slot, and it is likely
precipitation activity will have ended by then. Ridiculously
strong low level wind shear, as 0-1 KM bulk shear of 50+ knots
lifts through overnight, drawing concern for damaging winds and
and even non-zero tornado threat (see 17z HRRR STP fields 3-7 AM),
but near surface environment likely too stable to allow this to
happen, along with the overall limited cape/instability.
Good drying/subsidence to take place tomorrow with PW values
slipping back below half an inch, although low level moisture (2-3
kft)/clouds will likely take some time to scour out, which could
impact maxes slightly, otherwise 925 mb temps around 10 C (per 12z
nam) suggests maxes approaching 60 degrees.
Weak wave/850-700 mb Theta-E to lift through Tuesday evening, and
mid level lapse rates appear steep enough to possibility generate a
few high based showers. Despite the near zero showalter index
progged, left mention of thunder out, as soundings still indicated a
lot of dry air down low and significant cap.
Massive Upper Level Low/Trough centered over Red River Valley
will slowly wobble off to the East-Southeast, translating through
Great Lakes Region during Wednesday-Thursday Time Frame. Upper
level PV train/trough axis over Four Corners region tomorrow,
tracking through Ohio Valley on Wednesday, with cyclogensis taking
place over Eastern Ohio Valley, into the Eastern Great Lakes by
Wednesday Evening. Looks reasonable shot of rain shield clipping
southeast Michigan in this time frame, per 12z Euro.
The beginning of December will start off with longwave troughing
over the region through the end of the week before ridging builds
back in. Periods of showers will still be possible as the low
pressure system continues to push off towards the New England area.
Drier conditions come back for the the majority of the weekend
before more unsettled weather moves back in by the end of the
weekend. Temperatures will remain consistent through the extended
period with highs hovering around 40 degrees and lows around 30
degrees.
MARINE...
Southeast winds will continue to increase into tonight as a warm
front approaches from the south. This will lead to a period of gale
force winds throughout the Lake Huron basin, as well as the Michigan
waters of Lake Erie. Peak gusts during the overnight period will
climb to between 40 to 45 knots across northern and central sections
of Lake Huron. The long southeast fetch will also support extensive
wave growth, with waves potential peaking near 20 feet. Small Craft
Advisories will transition to Gale Warnings this evening. Winds and
waves are projected to improve Tuesday night into Wednesday as
direction shifts to the southwest and milder air and more stable
conditions overspread the region.
HYDROLOGY...
Rain will overspread the area late this afternoon and continue into
tonight as abundant gulf moisture lifts north into area in advance
of approaching warm front. This rain will come to an end early
Tuesday morning as the warm front progresses north of the region.
Total rainfall amounts of one half to three quarters of an inch are
expected across the region during this time frame. While this is an
above normal amount of rainfall for this time of year, flooding is
not anticipated.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
Lake Huron...Gale Warning until 4 PM EST Tuesday FOR LHZ363-421-422-441-462.
Gale Warning until 10 AM EST Tuesday FOR LHZ361-362-442-443-463-464.
Lake St Clair...Small Craft Advisory until 10 AM EST Tuesday FOR LCZ460.
Michigan waters of Lake Erie...Gale Warning until 7 AM EST Tuesday FOR LEZ444.
&&
$$
UPDATE.......CB
AVIATION.....CB
DISCUSSION...SF/SS
MARINE.......DG
HYDROLOGY....DG
You can obtain your latest National Weather Service forecasts online
at www.weather.gov/detroit.
Area Forecast Discussion
National Weather Service Grand Forks ND
942 PM CST Mon Nov 28 2016
.UPDATE...
Issued at 935 PM CST Mon Nov 28 2016
Continue to refine pops and precipitation type into the early
morning hours although changes minor. Cando and Devils Lake which
had earlier switched over to light snow have transitioned back to
light rain. This in line with high resolution model guidance which
is dropping warmer air aloft currently over the far northern fa
southward into east central ND by morning. This should limit any
significant accumulations over western fringes of east central
North dakota currently showing best snowfall from regional web
cams.
UPDATE Issued at 633 PM CST Mon Nov 28 2016
Current impulse rotating around upper low impacting mainly the
north half of the forecast area. Most high resolution model
guidance continues to rotate band west and southwest overnight.
May see more mixed rasn this evening over the n-nw however HRRR
warms 925mb temperatures overnight so current thinking of minor
accumulations seems reasonable. Made some pop adjustments to
account for near term radar trends but overall current forecast
on track.
&&
.SHORT TERM...(This evening through Tuesday)
Issued at 328 PM CST Mon Nov 28 2016
Forecast continues on track so overall little change was made.
Upper low drifting a bit west now toward Cooperstown. Radar has
been showing an area of rain on north and west side of the upper
low continuing to move west and northwest with additional rain
spreading north to the east of the upper low attm. So message is
at least into the evening is highest chances for precipitation
eastern ND with a dry slot into the southeastern and eastern fcst
area.
850 mb temps remain a bit above zero north of the upper low into
northeastern ND back toward DVl basin. This warm layer hangs
around tonight then goes away Tuesday. Surface temps continue to
slowly warm a bit into northeastern ND but overall expect not a
big temperature range tonight due to thick clouds and low level
moisture. Temps in area of concern...W of DVL and Cando and
Langdon 33-34F and dont expect any change. It would be a mix of
snow and rain this evening with these bands and with temps as they
are impacts should be minimal. But something to watch closely.
Tuesday will see the moisture being cut off from the upper low and
a transition to more drizzly weather with patches of wet snow.
Temps above freezing so again little impacts anticipated.
.LONG TERM...(Tuesday night through Monday)
Issued at 328 PM CST Mon Nov 28 2016
Tuesday night to next Monday...Overall weather impacts to be
confined to light precipitation mid week and a gradual cooling trend
into the weekend. Highest chances for light snow will be Wednesday
morning with accumulations around an inch possible. Light snow will
mix with rain during the daytime hours limiting accumulations. Upper
low pressure system will finally move enough to the east ending the
potential for measurable precipitation during the day Thursday as
saturation aloft diminishes, read no seeder/feeder mechanism and
less upper level lift. North winds on the backside of the departing
system Thursday will draw a bit cooler air into the northern plains.
As a result the end of the week and into the weekend will be dry
with temperatures ranging from around 30F for highs and teens or low
20s for lows depending on cloud cover.
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 633 PM CST Mon Nov 28 2016
CIGs waffling between mvfr/ifr conditions however expect general
lowering during the overnight into mainly ifr. VSBY currently not
much of an issue and not really anticipating anything blo mvfr
categories through the period.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...None.
MN...None.
&&
$$
UPDATE...Voelker
SHORT TERM...Riddle
LONG TERM...JK
AVIATION...Voelker
Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
915 PM EST Mon Nov 28 2016
.SYNOPSIS...
Moisture levels will steadilly increase ahead of an approaching cold
front tonight and remain high over the next few days. This will
bring much needed rainfall to the area through Wednesday. Cool and
dry high pressure returns Thursday and lingers through the weekend.
&&
.NEAR TERM /THROUGH TUESDAY/...
As of 900 PM EST...The core of the southerly LLJ looks to be
crossing the western NC mountains at the moment. The NAM and RAP
soundings show favorable lapse rates up to about 825 mb for mixing
some gusts down to at least 3500 ft elevations. I have opted to
upgrade Graham County to the High Wind Warning. The rest of the Wind
advisory looks good. Meanwhile, spotty light showers are beginning
to blossom across the southern and central NC mountains as moist
upslope and upglide flow. A narrow low-topped line of convection is
starting to show signs of weakening, especially across central TN.
The latest HRRR now just brings a blob of moderate rain into the
western mountains in the next couple of hours, but tries to
re-develop a line on the backside and bring that in around 6 am.
That line looks weak on the simulated reflectivity, however.
Meanwhile, a pseudo-wedge seems to be developing, despite no precip
to lock in cold air at the moment. The near term models may be
struggling with an in-situ CAD event developing once rain starts
falling. Not sure what will win out, as stout SELY BL flow should
win out. Temps are about 8-10 degrees warmer on the south side of
the boundary. I updated the temp and DWPT grids with CONSSHORT thru
daybreak Tuesday, which shows generally steady to warming temps
overnight.
As for precip, guidance still looks on track per trends. So no
changes were made to the PoP or QPF grids.
Otherwise, a very broad upper trough has set up from the Rockies,
Plains, to the Great Lakes, with a vorticity maximum lifting
northeast from the base of the trough to the eastern Great Lakes by
midday Tuesday.
At the surface, a cold front will reach the Southern Appalachians
overnight, and push to the Eastern Seaboard on Tuesday. Copious
moisture ahead of and along the front will support robust, but not
excessive, precipitation, especially over the Southern Blue Ridge,
where upslope flow will coincide with isentropic upglide.
Thunderstorms will be possible on Tuesday, but confidence is limited
on the possibility of severe weather. Precipitation should diminish
on Tuesday as the boundary moves east of our area. Winds will
increase overnight, especially at higher elevations. Winds above
3500 feet are expected to meet wind advisory criteria, and winds
above 5000 feet could be even stronger. Temperatures will run well
above normal tonight and Tuesday.
&&
.SHORT TERM /TUESDAY NIGHT THROUGH THURSDAY/...
As of 200 pm EST Monday: Very good model agreement is indicated at
the start of the short term period Tuesday night as a closed 500 mb
low spins over the upper Midwest and a sharpening trough axis swings
around the system through the southern plains. East of the trough, a
140+ kt upper jetlet will sharpen up over the OH valley Tuesday
night and provide increasing upper divergence through Wednesday.
Deeper moisture will gradually return to the southwest NC mountains
late Tuesday night and then steadily march east across the region on
Wednesday accompanied by a prominent low level jet. The one forcing
feature that is somewhat disappointing during this period is the
upstream trough which deamplifies as it approaches the southern
Appalachians. Still, deep layer south to southwest flow ahead of the
approaching surface cold front will push an established plume of
1.5+ inch precipitable water back into the region to support some
moderately heavy QPF. Widespread flooding is not expected given the
expected modest rates.
The southerly low level jet will likely be at it`s most intense
during the day on Wednesday, with 50 kt of 850 mb flow quite common
as the system translates east. Also, deeper mixing is expected
which should support higher wind gusts - even eastward over the
piedmont. A wind advisory could be needed on Wednesday and will
likely feature an HWO tag this afternoon for high winds on
Wednesday. Surface based instability looks somewhat limited but any
narrow convective lines embedded in the precipitation will need to
be closely monitored.
Anticipate post fropa drying from the west overnight Wednesday night
with a dry mid level westerly flow in place on Thursday. Some
moisture may return in the westerly flow at low levels on Thursday
but it appears too shallow for much upslope precipitation.
Temperatures by late day would support some snow mixing in at the
highest elevations if any precipitation does manage to fall. But,
will keep PoPs sub slight chance for now.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
As of 230 PM EST Monday: The first part of the extended will be dry
in the wake of the near/short term systems and with southwest flow
aloft over the area. The upper low over southeast Canada and the
eastern Great Lakes will continue to spin while slowly shifting
northeast, and with confluent flow over the Ohio Valley the high
pressure over the Plains will continue to ridge into the Southeast.
Meanwhile a deep trough over the Desert Southwest at the beginning
of the period will also begin to slowly slide to the east, bringing
eastern Pacific moisture into the southern Plains where low level
southerly flow will bring Gulf moisture into the mix. Guidance is in
pretty good agreement through Saturday with dry weather still
dominating, but with a general cooling trend in place as thicknesses
decrease and clouds begin to increase ahead of the next system.
It`s that next system that starts causing more problems, not only in
the fact that rainfall totals continue to pile up but also the
marked differences in model guidance. The ECMWF continues to phase
the Desert Southwest upper low with a trough pushing through Canada,
resulting in one deep high amplitude trough and a significant
surface low lifting from the southern Plains into the Mid-South
Saturday. Moisture streams into the Southeast and Southern
Appalachians with warm frontal precip moving into the area overnight
Saturday night with a hybrid damming event trying to develop, and
then the strong surface low lifting west of the Appalachians
bringing cold frontal precip to the region Sunday night. The GFS is
totally different with the low remaining cutoff and the Canadian
shortwave pushing through the center of the country over the weekend
but suppressing the precipitation farther south, not lifting up into
our area until the very end of the period. GFS ensembles and the CMC
support the GFS operational solution which has actually been fairly
consistent, whereas the UKMET supports the ECMWF solution. WPC has
generally taken a blend but leaned more toward the GFS. Consensus
data, as a result, bring mid-range chance pops into the area
Saturday night and linger them with some fluctuations through the
end of the period. This blended forecast is okay for now since we`re
still talking 5-7 days out, but at some point guidance will begin to
converge and we will be able to narrow this down. It will be
interesting to see if that convergence is toward the GFS, ECMWF, or
somewhere in between. In either case, another round of heavy rain
is anticipated, though the ECMWF has higher QPF understandably due
to the initial warm frontal precip (that is shunted south on the
GFS).
Additionally, looks like we have a decent shot of some p-type issues
across the northern mountains late in the period. Temperatures will
be highly dependent on moisture and precipitation so lowered
thresholds a bit before introducing frozen precipitation but do have
some snow and rain/snow mix creeping into the higher elevations each
night starting Saturday night. If the ECMWF is right some northwest
flow snow will be in the picture as the upper low swings over the
northern mountains.
&&
.AVIATION /02Z TUESDAY THROUGH SATURDAY/...
At KCLT and elsewhere: A sharpening boundary is setting up just
south of the Piedmont TAF sites. However, that is expected to lift
north and allow some mixing with gusty S to SE winds by around 03z
and thru the night. Meanwhile, deeper moisture should start working
in from the south and west within a strong low level jet, bringing
lower cigs and a round of moderate to heavy rain showers late
tonight thru at least midday Tuesday. There may be some
non-convective LLWS at KAVL and KCLT, as forecast soundings show
45-55 kts only 2000 ft AGL for much of the night. IFR to possibly
LIFR conditions are possible with this moisture. Then some
improvement is expected Tuesday afternoon, with a lull in precip.
Gusty south winds should subside slightly late afternoon.
Outlook: Another round of widespread rainfall and associated
restrictions, along with gusty southwesterly winds are expected on
Wednesday, as a slow-moving cold front crosses the region. Dry high
pressure returns Thursday and Friday.
Confidence Table...
02-08Z 08-14Z 14-20Z 20-00Z
KCLT Med 67% High 90% High 97% Med 78%
KGSP Med 72% Low 56% High 82% High 96%
KAVL Low 56% Med 72% Low 30% Low 57%
KHKY Med 66% Low 46% Med 70% High 98%
KGMU Med 73% Med 73% Med 76% High 94%
KAND Med 76% Med 70% High 87% High 92%
The percentage reflects the number of guidance members agreeing
with the scheduled TAF issuance flight rule category. Complete hourly
experimental aviation forecast consistency tables and ensemble forecasts
are available at the following link:
www.weather.gov/gsp/aviation
&&
.FIRE WEATHER...
A strong frontal system is expected to push in from the west tonight
and then stall across the region through Tuesday night. A trailing
cold front will cross the area Wednesday. Two separate rounds of
moderate to heavy rainfall are expected and these should provide a
good wetting rain on the ongoing fires. Expect rain totals of 2 to 4
inches in the mountains and 1 to 2 inches east. Windy conditions are
likely in the mountains tonight and again on Wednesday.
&&
.GSP WATCHES/WARNINGS/ADVISORIES...
GA...None.
NC...Wind Advisory until 7 AM EST Tuesday for NCZ033-049-050-053-
059-062>064-505.
High Wind Warning until 7 AM EST Tuesday for NCZ048-051-052-
058.
SC...None.
&&
$$
SYNOPSIS...SBK
NEAR TERM...ARK/JAT
SHORT TERM...HG
LONG TERM...TDP
AVIATION...ARK
FIRE WEATHER...
Area Forecast Discussion
National Weather Service Houston/Galveston TX
911 PM CST Mon Nov 28 2016
.UPDATE...
At 9:00 PM, the frontal boundary was located across the Houston
area and down near or over the inland portion of the coastal
counties east of highway 59. Am expecting the front to begin to
slowly move back inland during the night or early tomorrow
morning. Sea fog was noted over the Gulf waters. Over the land,
patchy fog was developing on the east side of the front. Dense
fog was already noted at Bay City and dense fog may become more
widespread later tonight between the frontal boundary and the
coast.
Updated forecast weather conditions and temperatures.
40/39
&&
.PREV DISCUSSION... /ISSUED 538 PM CST Mon Nov 28 2016/
AVIATION.../00Z TAF/
Upper level trough axis has pushed through but still another jet
streak coming across N Texas tonight. Dryline/Pacific Front has
stalled from KBMT to KLVJ and then down along the coast to KCRP.
Boundary should remain overnight and expected to push north in the
morning. South of boundary calm winds and clear skies will likely
lead to fog and restricted visibility. KHOU/KSGR will be on the
border of this with KLBX/KGLS having fog. KIAH will be watch as
well but concern may be more MVFR ceilings as boundary push north.
HRRR runs at 21/22z both hint at showers in the morning. Will not
put in TAFs yet but may monitor trends and add for 06Z update.
Ceiling should lift through the morning/early afternoon but
depends on how boundary evolves. Boundary should push back south
later in the afternoon with clearing conditions Tuesday night.
39
PREV DISCUSSION... /ISSUED 336 PM CST Mon Nov 28 2016/
DISCUSSION...
A frontal boundary continues to push southeast across the
forecast area this afternoon, stretching from a Livingston to
Tomball to Edna line as of 230 PM CST. Behind this boundary, drier
air has surged into the forecast area with dew points in the upper
30s and low 50s behind the boundary and upper 60s to low 70s ahead
of it. As an associated upper trough oriented almost vertically
across the Great Plains this afternoon continues to lift towards
the Great Lakes, this frontal boundary will continue to push
towards the coast and stall this evening as it loses upper
support.
The approach of this boundary has allowed the pressure gradient
to relax enough to allow the gusty southerly winds observed for
most of the day to subside and veer to the southwest, and expect
only light southerly winds overnight. With clear skies and light
winds overnight, expect patchy to areas of fog to develop within
the vicinity of the stalled frontal boundary (generally south and
southwest of the Houston metro). Have also included a mention for
patchy fog in the nearshore marine areas with warm, moist air
continuing to move across the cooler coastal waters south of the
boundary tonight. Otherwise, expect lows to range in the upper 40s
to mid 50s inland with mid 50s to mid 60s along the coast.
Warm conditions are expected again on Tuesday with highs in the
70s; a few locations west and southwest of Houston may even again
reach 80 degrees. The stalled boundary along the coast will lift
north during the day, possibly lifting to the Houston metro. May
see a few light showers as moisture returns back into the region
behind the boundary, with best chances for rain (20 PoPs) along
and south of the Interstate 59 corridor Tuesday afternoon as a
reinforcing cold front sweeps whatever Gulf moisture pushes back
into the region off the coast.
Drier and cooler conditions are expected behind this second cold
front with highs Wednesday through Friday in the 60s and lows
ranging from the upper 30s to near 60. Moisture begins to return
back to the region on Friday as an upper level system drops into
northwest Mexico from the Gulf of Alaska. Medium range guidance
continues to differ significantly with regards to what impact this
system will have for the region over the upcoming weekend, with
the GFS and Canadian cutting off a low over Mexico and the
European bringing a trough across the state by the end of the
weekend. This would offer vastly different scenarios for timing of
rain for the region, with the GFS/Canadian solutions keeping a
prolonged wet period from late Friday through Monday and the
European resulting in drier conditions almost a full day earlier.
Despite the disagreement on timing, guidance seems to be in
fairly good agreement for the development of a coastal trough with
precipitable water values climbing back above 1.5 inches (with
some guidance showing nearly 2 inches off the coast). This raises
concerns for the potential of heavy rain wherever the coastal
trough sets up and this portion of the forecast (particularly
Saturday and Sunday) will need to be monitored for a heavy rain
threat near the Upper Texas coast.
Huffman
MARINE...
Strong winds aloft mixing to the surface and a tight pressure
gradient will produce strong winds for the remainder of the
afternoon. Winds will drop off this evening in the wake of a weak
Pacific cold front. Elevated seas will remain above 7 feet for the
first half of the night and will maintain a Small Craft Advisory
through the evening hours. The front is forecast to go stationary
over the coastal waters and could wobble back onshore Tuesday
prior to a stronger cold front pushing into the Gulf late Tuesday
night. The return of SCA/SCEC conditions are likely for most of
Wednesday. A moderate east flow will develop on Thursday and is
then progged to strengthen significantly through the rest of the
week in response to a developing coastal trough. Mariners should
prepare for strong winds and elevated seas over the weekend and
another SCA will likely be required. This could produce increasing
tide levels during this timeframe and coastal flooding will be
possible Fri/Sat. 43
&&
.PRELIMINARY POINT TEMPS/POPS...
College Station (CLL) 54 73 46 65 39 / 10 10 10 0 0
Houston (IAH) 58 78 53 67 42 / 10 20 30 10 0
Galveston (GLS) 69 77 62 68 53 / 10 20 40 10 0
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...NONE.
GM...Small Craft Advisory until 4 AM CST Tuesday for the following
zones: Coastal waters from Freeport to the Matagorda Ship
Channel out 20 NM...Coastal waters from High Island to
Freeport out 20 NM...Waters from Freeport to the Matagorda
Ship Channel from 20 to 60 NM...Waters from High Island to
Freeport from 20 to 60 NM.
&&
$$
Discussion...40
Aviation/Marine...39
Area Forecast Discussion
National Weather Service Lincoln IL
913 PM CST Mon Nov 28 2016
.UPDATE...
Issued at 912 PM CST Mon Nov 28 2016
Rain is departing quickly to the northeast as dry air in the mid
levels arrives on brisk SW winds. Clouds are also clearing quickly
on the heels of the back edge of the rain. The NAM is indicating
we could see some low stratus could redevelop later tonight.
However, steady westerly winds the rest of the night should help
to preclude a strong low level inversion and low clouds from
developing, which is in line with the GFS.
Despite the clearing of clouds, which usually means colder night
time lows, steady winds should keep mixing in the low levels and
lows slightly warmer. Lows should settle out in the upper 30s NE
of the IL river, with mid 40s south of I-70.
Updated forecast info is already available.
&&
.SHORT TERM...(This evening through Tuesday)
ISSUED AT 230 PM CST Mon Nov 28 2016
Rather large storm system located over the northern Plains and
making its way into the Upper Midwest this afternoon is the dominant
feature on the weather map today. The cold front associated with it
is slow-moving, while plenty of warm air and moisture streams out of
the south up and into Central Illinois. This, in combination with a
few shortwaves making their way around the larger scale trof, is
resulting in plenty of showers and thunderstorms for Central
ILlinois. These showers are anticipated to come to an end later
this evening, clearing from west to east by midnight. Overnight
lows still well above norms for the end of November. Winds will
weaken from this afternoon, but still stay a little gusty at least
through the early evening. Tomorrow will be a much quieter day,
with the skies clearing and temperatures a bit warmer with all the
sunshine.
.LONG TERM...(Tuesday night through Monday)
ISSUED AT 230 PM CST Mon Nov 28 2016
The main cold front associated with the weather system that brought
precip to the area will finally move through the CWA Tuesday night.
This will allow more normal temps to be ushered into the area for
the remainder of the week and into the weekend. Even with the area
remaining in cyclonic flow through most of the week, dry weather is
expected through the rest of the week and into the first part of the
weekend. High pressure will finally build into the region at the end
of the week and into Sat. For the rest of the weekend, the model
show considerable differences. The ECMWF develops a large weather
system in the southern Miss valley and drives it north-northeast
into the Ohio valley. This solution allows colder air to drop into
the area, resulting in a higher potential of precip for Sat night
through Sun night. Obviously with the colder air, the precip type
would likely be snow. On the other-hand, the GFS just has a weak
wave moving through the zonal flow, through the area. Temperatures
are not colder and the any precip would be light and a probably a
mix of rain and snow, with mainly rain during the daytime hours. Due
to the differences being stark, best to keep a blend of the models
going that far out, keeping pops on the low side in the chance
category. Temps will likely be slightly below normal so precip type
will end up being a mix of rain and snow. This being the second day
in a row of the models being this different leads to low confidence
in the forecast for the weekend...so nothing to get excited about at
this time.
Again, temps will be above normal again tomorrow, with plenty of
sunshine and less windy. Beyond tomorrow, temps will fall to just
below normal, or around normal, for the remainder of the forecast
period.
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 557 PM CST Mon Nov 28 2016
Primary concern for the first 6 hours of the 00z TAFs will be the
how long to continue strong southerly winds before shifting to the
SW, along with timing the precip out of the area. The back edge
of steady rains has already progressed to a line near PIA to SPI
at 00z/6pm. Satellite and radar trends support the latest HRRR and
RAP guidance that show all of our terminal sites being clear of
rain by 06z/midnight, with CMI the last one to see rain end probably
before 05z.
IFR clouds will quickly improve to VFR shortly after the ending of
rainfall this evening, based on upstream OBS. Therefore, have
followed that theme in all TAFs, with improvement to VFR from
west to east starting at 02z at SPI through 04z at CMI. VFR
conditions should prevail the remainder of the TAF valid time.
Winds will remain in the 20G30kt range through much of the
evening. Gusts will become less strong as winds veer to the SW
from mid to late evening. Wind speeds may even sustain just below
10kt after 09z tonight, as the pressure gradient weakens and low
level jet dynamics shift to the NE of IL. Winds will increase from
the S-SW to 10-15kt tomorrow morning.
&&
.ILX WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...Shimon
SHORT TERM...HJS
LONG TERM...Auten
AVIATION...Shimon
Area Forecast Discussion
National Weather Service Northern Indiana
840 PM EST Mon Nov 28 2016
.SYNOPSIS...
Issued at 357 PM EST Mon Nov 28 2016
Widespread rain will persist into the overnight hours. While
breezy conditions will prevail tonight, an isolated stronger
shower or thunderstorm on the back edge of the area of rain may
produce wind gusts to 50 mph. Rainfall amounts of one half to one
inch are expected, causing ponding of water as well as minor river
rises in some areas. High temperatures for the day will occur
into this evening as rising temperatures are expected. Steady
temperatures overnight will climb higher on Tuesday with highs
well into the 50s to near 60. More seasonable temperatures will
return for the second half of the week.
&&
.UPDATE...
Issued at 821 PM EST Mon Nov 28 2016
Wind fields strengthening ahead of negatively tilted shrtwv
lifting ne across srn IL this eve with KIWX VWP indicating 45kt
in lowest gate. Sfc based inversion will limit downward transport
of these winds this evening but still expect some >40mph gusts.
Wk instability confined to trof axis. Latest HRRR/RAP suggests dry
slot will overspread our cwa ahead of the shrtwv, limiting
chances for tstms, but, will stick with slight chc through 06z,
and continue to monitor closely, as any deep convection will
enhance sfc gusts. Conditions this eve fcst well in going grids
and only minor adjustments made.
&&
.SHORT TERM...(This Evening through Tuesday)
Issued at 357 PM EST Mon Nov 28 2016
Deep low pressure over SE North Dakota was making its impacts felt
as far east as the Great Lakes where surge of anomalously moist
air was heading north into the region. Expect widespread rain to
take over the forecast area into this evening with average
rainfall amounts of 0.75 to nearly 1 inch. While this will cause
some local ponding as well as minor river rises, somewhat larger
concern looms in the 23Z to 05Z window as dry slot rapidly works
northeast into the area. HRRR has been steadfast in developing a
narrow line of strong showers/isolated storms on the back edge of
the rain. 0-1 km shear values in excess of 50 kts and 0-1 km
helicity values in excess of 500 m2/s2 would suggest a non zero
risk for isolated tornadoes. However, low level
inversion/stability may hold just enough to keep the threat at
bay. Strong wind fields aloft may be mixed down to bring several
reports of 40 to 50 mph winds with the line. A lot of uncertainty
with regards to the evolution and amount of inhibition at the
surface warrants adding thunder mention and patching up HWO to
reflect brief wind threat. Trends will be monitored into the
evening.
Otherwise...occluded front will quickly push through and bring any
rain to an end by Tuesday morning. Rising temperatures this
evening will steady out overnight and then climb further on
Tuesday with highs into the middle 50s to around 60, depending on
amount of sunshine.
&&
.LONG TERM...(Tuesday Night through Monday)
Issued at 357 PM EST Mon Nov 28 2016
Deep upper low will slowly drift east into Wednesday night,
forcing a cold front and a series of upper level disturbances
through the area. This and bringing an end to the above normal
temperatures expected into Wednesday. Not much moisture to work
with so precip chances will be limited but still worth a mention.
Upper low will center SE of James Bay and continue to send several
additional waves through the region into the weekend with
difficult to time chances for rain and/or snow. No major systems
expected at this point so only slight chc to chc pops warranted,
mainly in the north.
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday Evening)
Issued at 634 PM EST Mon Nov 28 2016
Strong storm across the region brings rain, winds and times of low
CIGs and VISBY. Expecting a period of IFR CIGs until around 07z,
when CIGs begin to trend higher. VISBY also looks to stay MVFR and
then increase around 05z as a dry slot begins to work into the
region. Am not totally confident that FWA goes has IFR CIGs for long
so only kept it in a temp group. Wind shear is also expected in the
early portion of the period with a low level jet nearby.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...Gale Warning until 4 AM EST Tuesday for LMZ043-046.
&&
$$
UPDATE...JT
SYNOPSIS...Fisher
SHORT TERM...Fisher
LONG TERM...Fisher
AVIATION...Roller
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Area Forecast Discussion...Updated Aviation
National Weather Service Saint Louis MO
559 PM CST Mon Nov 28 2016
.SHORT TERM... (Through Late Tuesday Afternoon)
Issued at 322 PM CST Mon Nov 28 2016
Rainfall over the eastern 1/3 of the CWFA will be ending from west to
east this evening as the "cold" front passes and drier air filters
into the area. Clouds are likewise clearing from west to east, but
are not moving out quite as fast as expected. Latest satellite pics
show the clearing line probably getting from central Missouri to the
St. Louis Metro area by 03-04Z...and then east to our CWFA border by
07-08Z. The RAP seems to have a decent handle on the clearing...so
have used it as the basis for my cloud forecast tonight. South to
southwest flow tonight into Tuesday isn`t exactly a cold wind...so
only expecting lows in the 40s tonight. Additionally there
should be a decent amount of insolation on Tuesday to go along with
the southerly flow. MOS looks reasonable with highs well above
normal again in the upper 50s to mid 60s.
Carney
.LONG TERM... (Tuesday Night through Next Monday)
Issued at 322 PM CST Mon Nov 28 2016
(Wednesday through Friday)
Still expect Wednesday through Saturday to be mainly dry. Both the
GFS and ECMWF are in good agreement that the upper low that will be
over the Upper Midwest on Wednesday morning will lift northeastward
through the Great Lakes and not bring any precipitation to the area.
In the meantime, zonal upper flow will setup at least through Friday
before the ECWMF and GFS begin showing diverging solutions to the
forecast over the weekend.
With polar cold front staying well south of the area during the
period and 850mb temperature staying around -5C, GEFS mean temps
support temperatures staying around normal values.
(Saturday through next Monday)
There continues to be great uncertainty with the forecast over the
weekend into early next week as the the ECMWF and the GFS are
showing different solutions. The GFS/GFS ensemble has shown more
continuity with bringing a northern stream trough across the area
Saturday night and Sunday which would bring some light rain/snow to
the area. The ECMWF on the other hand has not shown as much run to
run consistency, with it bringing out a larger, colder system over
the weekend that would have the potential to produce more snow.
Given the consistency of the GFS, will lean more toward it`s
solution at this point. Temperatures will continue to be close to
normal during the period.
Britt
&&
.AVIATION... (For the 00z TAFs through 00z Tuesday Evening)
Issued at 532 PM CST Mon Nov 28 2016
Quickly improving conditions this evng. Bulk of the precip pushed E
of the terminals this aftn and is now confined to Ern IL. Skies have
cleared considerably behind the precip as well. There may be a few
lingering sprinkles or light SHRAs prior to the passage of a cold
front this evng. There were some TSTMs that dvlpd along this bndry
late this aftn from near KCOU to KIRK and on into IA but have since
dssptd. Winds will become SWrly for several hours after FROPA but
should gradually come back around to the S. Tue should be a quiet
day with Sthrly winds aob 10kts with just some mid clouds.
SPECIFICS FOR KSTL:
VFR fcst thru the prd. Cloud deck will clear right at the start
of the TAF with just some scttrd VFR clouds this evng. FROPA this
evng will turn winds to the SW for several hours overnight but
should come back around to the S by 12Z Tue.
2%
&&
.LSX WATCHES/WARNINGS/ADVISORIES...
MO...None.
IL...None.
&&
$$
WFO LSX
Area Forecast Discussion
National Weather Service Melbourne FL
930 PM EST Mon Nov 28 2016
.DISCUSSION...
Update...Marine Stratocumulus clouds to continue to spread north
overnight. Evening soundings show pronounced marine layer with
inversion around 7kft. Press gradient supports atmosphere not
completely decoupling overnight with just a period of low stratus
forming over the interior. Along coast atmosphere should remain well
mixed. Both HRRR and local 2-6km WRF show coastal zone convergence
setting up from the Cape and points south. Will keep low chance
precip in forecast for this area. Recent profilers and model
guidance suggest not much inland movement to this activity and will
keep it restricted to coastal zone. Fairly mild overnight and
current forecast min temps on track.
***USERS NOTE*** The KMLB WSR-88D weather radar will be out of
service for much of this week for hardware and software upgrades.
Estimated return to service date is Friday Dec 2.
&&
.AVIATION...Overnight...period of MVF to IFR mainly over interior
as moist layer above surface saturates. Pressure gradient should
keep winds up enough to prevent surface fog. Over coastal locations
added VCSH in late night period to be consistent with other
forecasts. VFR all location TUE.
&&
.MARINE...
Tonight-Tuesday...Exercise caution conditions in nearshore waters
SCA continuing until Tuesday over offshore. Winds and seas improving
slowly overnight and on Tuesday and gradient slackens.
&&
.CLIMATE...
Record highs for Tue (29th) and Wed (30th):
DAB 29-Nov 87 1978
MCO 29-Nov 88 1978
MLB 29-Nov 87 1982
VRB 29-Nov 87 1986
DAB 30-Nov 85 1978
MCO 30-Nov 86 1982
MLB 30-Nov 88 1978
VRB 30-Nov 87 1976
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...None.
AM...Small Craft Advisory until 11 AM EST Tuesday for Flagler Beach
to Volusia-Brevard County Line 20-60 nm-Sebastian Inlet to Jupiter
Inlet 20-60 nm-Volusia-Brevard County Line to Sebastian Inlet 20-60
nm.
&&
$$
Blottman/Weitlich
Area Forecast Discussion...UPDATED
National Weather Service Mobile AL
813 PM CST Mon Nov 28 2016
.DISCUSSION...See updated information for land areas below.
&&
.UPDATE...Latest thinking for the next 6 hours suggests persistent
but progressive low level 850 jet now entering western sections of
the forecast area this evening with still very limited cape or
instability near the sfc suggesting convection moving in from the
west remains elevated for most inland areas and will likely do this
through the evening and overnight hours. After looking over some of
the hi res progs both the hrrr and ruc13 still bring in more
convection for this evening still leaving us with some concern though
with the better dynamics lifting off to the ne quickly through 06z
and still the lack of surface based instability we will likely see
more of the same trends on radar through around 2 or 3 am. Worst off
would be a bowing segment with maybe some winds briefly transitioning
to the sfc near the apex of bow. Further south near the coast and
offshore scattered showers with maybe a few thunderstorms mixed in
will become better developed through the night due to the better sfc
based instability over the gulf and possibly near the immediate coast
combined with the forcing aloft. As the better dynamics aloft moves
off to the north the threat for these storms to the south becoming
severe also lessens especially after midnight. With this will begin
to back off on the severe wording for the remainder of tonight...
especially east of the I-65 corridor...though continue monitor
closely. 32/ee
&&
.PREV DISCUSSION... /issued 559 PM CST Mon Nov 28 2016/
DISCUSSION...Updated for latest aviation discussion below.
AVIATION...
00Z issuance...VFR to MVFR cigs through 29.03 followed by most MVFR
cigs and visibilities through about 29.09z followed by IFR cigs and
visibilities through about 29.18z then IFR to MVFR cigs through
30.00z. Lower cigs and visibilities mostly in scattered to numerous
showers and thunderstorms moving across the region this evening and
overnight. Winds will continue from the south at 15 to 25 knots with
higher gusts through about 29.09z...diminishing to 10 to 15 kts
through 30.00z. 32/ee
PREV DISCUSSION... /issued 418 PM CST Mon Nov 28 2016/
NEAR TERM /Now Through Tuesday/...A large occluded mid-latitude
cyclone continues to spin on water vapor across the northern plains.
A short wave rotating through the base of the upper trof is
currently generating showers and thudnerstorms over the Arklatex
region where there is an enhanced severe weather risk this afternoon
and evening. Ahead of this system, windy conditions are underway
across much of the southeast with southerly winds of 20 to 30 mph
common, gusting to around 40 mph at times. A wind advisory continues
through 7pm. The Storm Prediction Center maintains a marginal risk
across much of our area with a Slight risk across northwest portions
of the area. As is typical this time of year, the kinematics are
there with 60-70 knots of 0-6km shear and a low-lvl jet increasing
to around 65 knots tonight. The question as it normally is, will be
the thermodynamics. Models agree that a very narrow band of
instability (CAPE) will nudge into the area late this evening and
overnight as a line of showers and storms is expected to develop to
our west and move eastward through the overnight hours.
As far as timing, scattered showers will develop across southeast
Mississippi this evening but are not expected to become severe. A
line of showers and thunderstorms will move into western parts of
the area between 7 pm and 9 pm and into and across southwest Alabama
(to the west of I-65) through around midnight. A few strong to
severe storms are possible along the line. The strong shear will
favor rotating updrafts if a strong enough updraft can develop.
However, we expect the tornado risk to remain extremely isolated
across mainly northwest portions of the area. The most likely event
will be a strongly forced squall line that will weaken as it moves
eastward tonight. Damaging straight line winds will be the primary
threat as it will not take much to mix down the strong winds aloft.
After midnight and through around 4 am or so, expected the weakening
line to continue east of I-65 in interior south central Alabama and
across the western Florida panhandle. Lows tonight will range from
the low 60s across northwest areas to low 70s along the coast.
Scattered rain showers will re-develop on Tuesday with a possible
embedded thunderstorm in the afternoon given continued southwest
flow aloft and potential for reloading instability. We may have to
watch for isolated strong storms Tuesday afternoon if enough
instability develops, however the better chances will be later
Tuesday night. Highs on Tuesday will be in the upper 70s to around
80. 13/JC
SHORT TERM /Tuesday night Through Thursday night/...Some isolated to
scattered showers and storms will continue to be possible Tuesdayevening,
then increased dynamics and omega will begin moving in from the west
around daybreak Wednesday and continue across the forecast area on
during the day. There is the potential for another round of strong to
possibly severe storms, with damaging winds again being the primary
threat. We will continue continue to monitor and fine tune the timing
and potential threats with this second round. Wednesday night through
Thursday night look to be rainfree and cooler as drier high pressure
builds east across the area. Lows tonight ranging from the low 60s
northwest to around 70 coastal tonight and Tuesday night, cooling to
upper 30s west to the low/mid 40s east by Wednesday night in the wake
of the front. Daytime highs in the upper 60s to mid 70s Wednesday and
cooling to the low to mid 60s across entire region on Thursday. 12/DS
LONG TERM /Friday Through Monday/...Rain chances gradually increase
through the long term period with a fairly active upper flow.
Scattered showers and storms expected each day. Remaining a little on
the cool side through the period. Daytime highs in the upper 50s to
upper 60s. Nighttime lows primarily in the 40s. 12/DS
MARINE...Strong southerly winds will continue through Tuesday
morning before decreasing slightly Tuesday afternoon. Winds increase
again Tuesday night into Wednesday as a cold front approaches from
the west. The cold front is expected to move through the marine area
Wednesday afternoon and evening with a moderate northerly flow in
the wake of the front. Small Craft Advisory is in effect for most of
the Marine area through Wednesday. Scattered to locally numerous
showers and thunderstorms can be expected tonight into early Tuesday
and again late Tuesday night into Wednesday. Some of the storms may
be strong to severe. 12/JC
&&
.MOB WATCHES/WARNINGS/ADVISORIES...
AL...High Rip Current Risk through Tuesday afternoon for ALZ265-266.
High Surf Advisory until 6 AM CST Tuesday for ALZ265-266.
FL...High Rip Current Risk through Tuesday afternoon for FLZ202-204-
206.
High Surf Advisory until 6 AM CST Tuesday for FLZ202-204-206.
MS...None.
GM...Small Craft Advisory until noon CST Tuesday for GMZ630>635.
Small Craft Advisory until 6 PM CST Wednesday for GMZ650-655-670-
675.
&&
$$
This product is also available on the web at:
http://weather.gov/mob
Area Forecast Discussion...UPDATED
National Weather Service Marquette MI
1008 PM EST Mon Nov 28 2016
.UPDATE...
Issued at 1006 PM EST MON NOV 28 2016
No big changes to going forecast. Widespread rain, falling moderate
to even heavy at times, will continue to lift across all of Upper
Michigan through the overnight hours. Already have seen hourly
rainfall rates at some spots over scntrl and eastern cwa up near 0.40
inch/hour.
Does appear that there will be a rather abrupt end to the rain per
the latest high res guidance which matches upstream radar decently.
Expect the rain to end along WI border 10z (5 am ET) and around 12-
13z (7-8 am ET) near Lk Superior and over eastern cwa. Back edge of
rain has carried along with it isold tsra much of this evening.
Since edge of steeper mid level lapse rates 6.5c/km clips
southeast/east cwa as the rain ends it is possible there could be
isold tsra or at least rumble of thunder at ISQ and ERY late
tonight. Way too low of coverage to put in forecast, but it will be
interesting to see if it does occur. Approaching occluded front
extending from strong low pressure over Dakotas this evening will
sweep south to north across Upper Michigan late tonight switching
winds to more sw instead of current se direction. Could be brief
duration when dense fog could occur late tonight as rain ends, but
soundings show sharp drying all the way down to sfc. Drying along
with less favorable upslope flow should mitigate the dense fog, or
at least keep lid on long duration of dense fog.
Based on limited new model guidance and satellite and upstream obs,
brought clouds and chance of rain quickly back over west half of cwa
on Tue. Much lighter precip compared to tonight, but based on
NAM/GFS wet bulb zero heights, could see rain/snow mix over higher
terrain of west as early as late morning as the cooler air currently
over the eastern Dakotas begins to filter over WI and southwest Upper
Michigan. &&
.SHORT TERM...(This evening through Tuesday)
Issued at 413 PM EST MON NOV 28 2016
WV imagery and RAP analysis indicated a broad mid/upper level trough
over the plains with a low centered over ern North Dakota. At the
surface, a 975 mb low was located over se ND with an occluded front
looping through ern MN into cntrl IA. The combination of a shortwave
trough and strong moisture advection supported a large area of rain
over WI that was quickly spreading to the north.
Tonight, the area of strong 700-300 mb qvector supporting the
upstream pcpn over WI is expected to lift to the nne through Upper
Michigan this evening and diminish across the cwa from sw to ne
between 06z-12z. So, the area of drizzle will give way to a steadier
moderate rain. With pwat values from 0.75-0.90 inch, QPF amounts in
the 0.50-1.00 inch will be common, especially over the southeast
half. Signficant drying will then move in late over the west and
south. Temps will remain well above normal with lows in the low to
mid 40s.
Tuesday, with the occluded front lifting to the north of the area
and qvector div and subsidence taking over, expect mainly dry
weather. Some wrap-around pcpn may sneak into the far west from nw
WI late. Otherwise, expect breezy southwest winds with temps slowly
falling into the upper 30s west. However, some sunshine over the
east half will help boost readings into the upper 40s.
.LONG TERM...(Tuesday night through Monday)
Issued at 343 PM EST MON NOV 28 2016
The low pressure system currently W of the region will weaken and
slowly meander across the area through Thu, with a couple other
waves possible coming down the back side of the system later in the
week. Colder air moves in late this week into Sat as an upper trough
moves out of NE Canada and into northern Ontario and Quebec. Early
next week is quite uncertain as models show differing solutions with
a system moving through the region.
Ptype will be driven largely by wet-bulb zero height, meaning more
snow during the night and over the higher terrain, and snow chances
will increase through the end of the week as the airmass gradually
cools. Best QPF through Sat looks to be on Thu when a shortwave
moves around the back side of the departing system and the SFC
trough swings through. However, mild SFC temps will keep precip
mixed or at least limit snowfall amounts with snow melting some as
it falls. Still some uncertainty there, but not a big concern at
this time.
Looking way out there, deterministic models are suggesting a much
colder trend beyond 10 days out, which is backed up with the CFS.
CFS also builds a large mass of very cold air across AK and the NW
Territories toward the end of Dec, which would signal a significant
pattern change.
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 649 PM EST MON NOV 28 2016
Low level moisture streaming into the region ahead of a deep low
pressure and frontal system will maintain the low clouds into early
Tuesday. The downslope component with the se to s flow will keep
cigs mainly in the MVFR range at IWD. However, IFR/LIFR cigs are
expected at CMX and especially SAW. Light rain will be overhead much
of the night before diminishing late tonight or around daybreak on
Tue. Fog through the night should be not as dense as the rain is
around, but if there is a break in the rain, may see a brief period
of dense fog, especially at SAW and CMX. Drier air moving into the
area behind the occluded front as winds veer sw will bring improving
conditions by mid Tue morning into early Tue aftn. For the most part
expect MVFR cigs with no vsby reduction but cigs could even
reach VFR levels at SAW.
&&
.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 413 PM EST MON NOV 28 2016
Southeast gales in the tight pres gradient ahead of the deep ND low
will gradually shift off to the northeast tonight into early Tuesday.
The low pressure system will linger over the Upper Midwest Tuesday
into Wednesday. However the pressure gradient is not expected to be
as tight and should allow winds to diminish below 25kt by Tuesday
afternoon. Northerly winds to around 25 knots may develop Thursday
as the slow moving low moves to the east of Lake Superior into
Quebec.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
Gale Warning until 10 AM EST Tuesday for LSZ249>251-266-267.
Gale Warning until 4 AM EST Tuesday for LSZ243-244-264-265.
Gale Warning until midnight EST tonight for LSZ245>248-263.
Lake Michigan...
Gale Warning until 4 AM EST Tuesday for LMZ248-250.
&&
$$
UPDATE...JLA
SHORT TERM...JLB
LONG TERM...Titus
AVIATION...JLA
MARINE...JLB
Area Forecast Discussion
National Weather Service Pittsburgh PA
854 PM EST Mon Nov 28 2016
.SYNOPSIS...
A series of disturbances will provide periodic rain chances to
the forecast tonight through the mid week.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
Rain shield is still having issues moving east, due to the dry
airmass in place and also due to east/southeast winds which are
downslope for much of the forecast area. Have backed off a little
further on eastward precipitation advancement in the grids based
on radar/hi-res trends. The other issue is temperatures, as the
models are struggling to handle this non-diurnal regime. This is
especially true along the east-facing slopes of the ridges, where
a cold air damming-type setup is in place, with a few readings in
the 30s in Garrett County. Have used modified HRRR hourly grids
for the overnight forecast, still showing rising temps later
tonight, but more slowly, and hold on to colder air in the far
east longer. Not expecting any precip type issues, as the column
remains warm enough for all rain. Strengthening low-level jet
overnight will lead to gusty winds, but advisory-level gusts will
remain locked above an inversion.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH THURSDAY/...
The front and precipitation are progged to exit the region
Tuesday morning. Further warm advection via southwest flow will
raise temperatures nearly 20 degrees above average. The second
shortwave from the parent upper low is progged to track across
the Upper Ohio Valley region Tuesday night through Wednesday, with
another period of rain supported by deep moisture, ascent, and low
level jet support.
The third shortwave rotating around the upper low is progged for
a Thursday passage with slight to low chances for rain and
possible snow showers. Temperatures should be well above seasonal
levels through midweek, before cold advection returns them to near
average by Thursday.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
The upper low is progged to track across Eastern Canada through
late week with upper troughing extending across the Northeast
CONUS. The pattern is progged to become less amplified by the
weekend with a series of crossing upper troughs expected. This
should keep periodic rain and snow shower chances and near to
below seasonal average temperatures in the forecast. Followed
close to NAEFS guidance and WPC progs which steered away from a
very amplified ECMWF pattern depiction late in the period.
&&
.AVIATION /02Z TUESDAY THROUGH SATURDAY/...
Prevailing VFR will transition to MVFR as a frontal boundary
crosses the region overnight. With plenty of dry air at the
surface, it may take some time before the lower cloud deck makes
its way into ZZV and eastward. However, a period of MVFR ceilings is
anticipated everywhere, with brief visibility restrictions also
possible in heavier rain. This system should be quickly east of
the region by morning with improvement expected.
The presence of a strong low level jet will support wind shear
across several of the terminals overnight in advance of the front.
Wind gusts may approach 50kts at above 2kft. Thus, this has been
mentioned until the passage of the front tomorrow morning, when
steepening lapse rates will allow for some wind gusts to mix to
the surface. By this time however, the strongest wind aloft will
have moved off to the northeast so gusts will generally be 20kts
or less.
.OUTLOOK...
Another round of rain and restrictions will be possible Wednesday
into Thursday with the passage of another front.
&&
.PBZ WATCHES/WARNINGS/ADVISORIES...
MD...None.
OH...None.
PA...None.
WV...None.
&&
$$
Area Forecast Discussion
National Weather Service Springfield MO
508 PM CST Mon Nov 28 2016
.SHORT TERM...(This evening through Tuesday)
Issued at 241 PM CST Mon Nov 28 2016
Initial shortwave rotating around the deep upper low over the
northern Plains was pushing through the area, with the main
precipitation shield now over the eastern Ozarks. Skies were
clearing across southeast Kansas and far western Missouri just
behind a surface boundary. This clearing will continue to progress
eastward through the late afternoon and early evening hours. 17Z
RAP model does show some instability over the eastern Ozarks
early this evening, so have kept lower end probabilities going.
Cannot rule out some small hail with any of the storms that may
develop.
Otherwise, upper low will continue to meander over the northern
Plains through Tuesday pushing a weak frontal boundary through
southeast Kansas and the Missouri Ozarks Tuesday afternoon. Front
will pass through dry, with just a wind shift to the west southwest.
temperatures will again be mild with highs in the upper 50s to lower
60s.
.LONG TERM...(Tuesday Night through Monday)
Issued at 241 PM CST Mon Nov 28 2016
Surface low over the upper Midwest will gradually shift into the
Great Lakes region through Thursday. The latest NAM and GFS show
some decent moisture wrapping around the back side of this system
and clipping central Missouri Wednesday night. However all precip
remains north of our area, so will keep this portion of the
forecast dry.
Next storm system to impact the CONUS will drop southward from the
northwest Pacific into the Desert Southwest by Friday/Saturday.
The system will tap into a deep moisture fetch over the eastern
Pacific and spread it northeastward into the central US by
Saturday night and Sunday. While it looks like the main
precipitation type will be rain with this system, temperatures
will be close enough to the freezing mark to possibly support
rain/snow mix, mainly late Saturday night and early Sunday. Will
be following the GFS solution for movement of this system as the
ECMWF continues to shift the system too quickly to the east.
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 504 PM CST Mon Nov 28 2016
Drier air was pushing into the area behind a frontal boundary and
was clearing the sky from west to east. All of the TAF sites had
cleared out or will clear out by 00z. A secondary front will push
into the area on Tuesday, but with drier air in place, not
expecting much other than some mid level clouds ahead of the
front.
&&
.SGF WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&
$$
SHORT TERM...Raberding
LONG TERM...Terry
AVIATION...Lindenberg
Area Forecast Discussion
National Weather Service Tucson AZ
905 PM MST Mon Nov 28 2016
.SYNOPSIS...A few light valley rain and mountain snow showers will
occur mainly from Tucson eastward into Tuesday morning. Much cooler
temperatures and the coldest lows of the season so far Tuesday night
and Wednesday night, with widespread freeze or hard freeze
conditions for Southeast Arizona. Temperatures will remain below
average through the week, and another storm system may bring a
chance of valley rain and mountain snow Friday into the weekend.
&&
.DISCUSSION...IR satellite imagery depicts mostly cloudy to cloudy
skies across southeast Arizona this evening, with broken to overcast
mostly lower level clouds as per several surface observations valid
8 pm MST. A broad upper trough extended from the intermountain west
eastward into central CONUS plains. A speed max/vort lobe was
embedded within the southwestern periphery of this upper trough as
per the 29/00Z upper air plots. IR satellite imagery also depicted a
distinct back edge to the lower level clouds, with clearing skies or
mostly clear skies from KPHX northwestward into southern Nevada.
A linear extrapolation of this back edge of lower clouds feature
would suggest that clearing skies would encroach upon the Tucson
metro area within a few hours, or perhaps around 11 pm - midnight or
such. However, some hi-res models such as the HRRR and the 29/00Z
Univ of AZ WRF-NAM suggests a potential for at least isolated valley
rain/mountain snow showers from near Tucson eastward to the New
Mexico into Tuesday morning.
Thus, am inclined to make no changes to the inherited official
forecast at this time. Expect isolated to scattered valley rain/
mountain snow showers into Tuesday morning. The exception will be
across western Pima County where precip-free conditions are
expected. Any rain amounts at lower elevations will be quite light,
or mostly less than 0.10". Snow accumulations (as noted in the
Previous Discussion) should only be from 1-2 inches or so above
5000 feet.
A few lingering showers may occur Tuesday afternoon across southern
Cochise County. Clear skies or mostly clear skies will then prevail
Tuesday night into Wednesday morning, setting the stage for the
coldest night of the season thus far. A Freeze Watch and a Hard
Freeze Watch will continue from late Tuesday night through Wednesday
morning. Please refer to AWIPS product PHXNPWTWC - WMO header WWUS75
KTWC for more information.
&&
.AVIATION...Valid through 30/06Z.
Expect isolated to scattered -SHRA and mountain -SHSN mainly KTUS
eastward to the New Mexico border into Tuesday morning. MVFR
conditions will occur especially across higher terrain. A few
lingering -SHRA mostly from KFHU-KDUG Tuesday afternoon, then
clearing skies Tuesday evening. Surface wind east/south of KTUS
wly/nwly at 10-18 kts with gusts to 25 kts. Surface wind KTUS
vicinity westward generally less than 10 kts thru the period.
Aviation discussion not updated for TAF amendments.
&&
.FIRE WEATHER...A few valley rain and mountain snow showers will
occur from Tucson eastward into Tuesday morning, then a few showers
across southern Cochise County Tuesday afternoon. Dry conditions
will then occur Wednesday into Thursday. A low pressure system may
then bring more wintry weather and gusty east winds Friday into
this weekend.
&&
.PREV DISCUSSION /145 PM MST/...Latest water vapor imagery shows
northwesterly flow aloft across the forecast area with one final
disturbance near the CA/NV border moving southeast. There is still
considerable low to mid level clouds north of Tucson and partly
sunny conditions with mainly cirroform clouds for the remainder of
the forecast area. Latest model trends have generally backed off a
bit on this final moisture starved system tonight into Tuesday
morning. Still looking at a few showers and mountain snow showers
starting as early as this afternoon across the White Mountains, then
continuing tonight into Tuesday morning, mainly from Tucson north
and eastward. Another inch or two of snow is possible in the
mountains from Tucson north and east with snow levels will be around
5000 feet. This system will also keep temperatures from crashing
overnight.
The aforementioned disturbance will move east of the area Tuesday
morning with any residual chance of showers coming to an end. With
skies clearing through the day from west to east, this will set the
stage for the coldest night of the season for Wednesday morning. A
freeze watch remains in effect for most desert locations from Tucson
westward except the far western deserts near Ajo and Organ Pipe
National Monument. A hard freeze watch is also in effect for much of
Santa Cruz County and the higher elevations of South Central Pima
County including the Arivaca and Sasabe areas which haven`t had a
widespread freeze yet. The eastern valleys of Graham/Greenlee/
Cochise counties will also see a hard freeze but these locations
have had a widespread freeze already this season so will not issue
any headlines there.
Fairly benign and continued cool on Wednesday and Thursday with dry
westerly flow aloft. Thursday morning will be rather cold once again
but likely a couple of degrees warmer than Wednesday morning. By
Friday into the weekend our attention focuses toward a closed low
that will move south from the Great Basin into Arizona and then
possibly northern Mexico. Still lots of uncertainty with this system
as the ECMWF has been depicting a much more progressive and open
wave solution compared to the GFS/CMC for the past couple of runs.
Will lean towards the GFS/CMC and GEFS ensemble mean which is
somewhat slower and more closed off than the ECMWF. Regarding
sensible weather, will maintain slight chance to low end chance PoPs
starting Friday, then continuing into Saturday before winding down
on Sunday. Early indications are that snow levels will be about 5000
feet with this system.
&&
.TWC WATCHES/WARNINGS/ADVISORIES...
Freeze Watch from late Tuesday night through Wednesday morning for
AZZ502-504>506.
Hard Freeze Watch from late Tuesday night through Wednesday
morning for AZZ503.
&&
$$
Visit us on Facebook...Twitter...YouTube...and at weather.gov/Tucson
Area Forecast Discussion...UPDATED
National Weather Service BROWNSVILLE TX
1118 PM CST Mon Nov 28 2016
.DISCUSSION...Updated for latest aviation discussion below.
&&
.AVIATION...A weak frontal boundary lies across the middle of
the area, but there should be little additional movement toward the
Lower Valley tonight. Elevated dew points under initially mostly
clear skies and a low level inversion will promote fog near the
coast. Winds should remain no less than 5 to 10 mph however, at
least slightly hindering denser fog. Still, may see visibility drop
to a half mile at the TAF sites for a few hours around dawn, along
with the advection of low level marine based clouds. Conditions will
improve mid morning as winds increase again.
&&
.PREV DISCUSSION... /issued 526 PM CST Mon Nov 28 2016/
DISCUSSION...Updated for latest aviation discussion below.
AVIATION...Below average confidence still for dense fog at the
TAF sites, though MVFR after midnight and tempo IFR look pretty
good and were included in the TAFs. A frontal boundary is moving
into the Ranchlands and Brush Country with lower dew points, but
the HRRR for example doesn`t quite bring it through.
PREV DISCUSSION... /issued 253 PM CST Mon Nov 28 2016/
SHORT TERM (Tonight through Tuesday Night): Base of upper trough
moving across NC Texas with the strong LLJ getting shunted
eastward. This shows up nicely on local doppler radar with veering
winds gradually spreading west to east through the morning. The
associated cold front, moving through the Hill country and into SC
Texas, is expected to slow down and pull up stationary over the
CWA later tonight. This will set the stage for fog development
after midnight as light SE winds usher in very shallow but high
dew point air. Models are a bit indifferent if there will be a low
stratus deck or the potential of dense fog. The favored areas
will be across the Mid and Lower Valley in the vicinity of the
anticipated stalled front. Models also show the worse conditions
around and shortly after sunrise when saturation reaches its peak.
Confidence is slight below average to issued a dense fog advisory
at this time with model uncertainty. With the front passing
through approximately half of the CWA temperatures will cooler
across the NW Zones with another much above normal night in the SE
half.
The next upstream shortwave tracks across Texas later Tuesday with a
stronger cold front moving through the CWA Tuesday night. A non
eventful day is on tap with mostly cloudy to cloudy skies in the
morning with partial clearing in the east later in the afternoon as
low level moisture is shown to increase. the front is not expected
to bring rain with depth of the moisture remain below 850mb.
However, some streamer showers may develop over the Coastal waters
tomorrow night with a few possibly moving into the Lower Valley.
Otherwise, another warm day is in store with temperatures ranging in
the mid 80 to upper 80s and a few locals reaching 90 degrees in the
Mid Valley if the sun breaks out in time.
LONG TERM (Wednesday through Monday):
Beginning of the long term starts with the passage of the finale
of the cold front passage Wednesday morning. Still looks like
precipitation will be limited to mainly offshore waters. Dry air
sweeps in fairly quickly during the afternoon, so skies should be
nearly clear by sunset. This will provide for good radiational
cooling Wednesday night, with lows either side of 50 degrees. Weak
onshore flow returns on Thursday, slowly building cloud cover from
the coast inland.
The weekend forecast is still muddled by a considerable upper low
dropping into northwest Mexico. Most models are fairly consistent
with the low stalling across northwest Mexico most of the weekend,
with hints that it finally ejects starting Monday. This setup will
induce coastal troughing just offshore from south Texas for the
weekend, which produces a good overrunning pattern. Friday and
Saturday, all models are in good agreement on widespread
light rainfall for the region. Now the outlier model is the EC,
which depicts the cutoff low not really cutting off and quickly
jumping into the central US by Sunday. This would bring the
moisture to an end early and leave a drier Sunday and Monday. As
this seems to be the outlier of the remaining models, have opted
to discount the EC model, in favor of a blend of the remaining
models, which keep moisture and rainfall in the region through
Monday. With this in mind, have pushed PoP chances back up to low
end likely through Monday, before tapering off for Tuesday as the
cutoff low finally ends.
MARINE:
Now through Tuesday Night: South winds and the high seas will
continue to lower tonight as a cold front approaches the coastal
bend but residual higher seas may linger until between 9 pm and
midnight maintaining SCA`s offshore. the front pulls up stationary
and will be waiting for a reinforcing high pressure to push it
through around late Tuesday night or by sunrise Wednesday. In
advance of the wind shift expect a moderate southeast flow with a
moderate sea maybe high enough to warrant exercise caution
conditions. Small craft advisories are likely to be issued for the
early Wednesday cold front passage.
Wednesday through Friday: Winds behind the front Wednesday morning
will jump quickly to 20 to 25 knots, while seas jump to 8 to 10
feet with higher swells late in the afternoon. Conditions will
relax fairly quickly Wednesday night with onshore flow returning
Thursday morning. The coastal trough will develop by Friday
morning, with agitated conditions forecast through much of the
weekend. Seas will jump up to 9 to 12 feet for the weekend, with
winds onshore of 20 to 25 knots.
&&
.BRO WATCHES/WARNINGS/ADVISORIES...
TX...None.
GM...Small Craft Advisory until 3 AM CST Tuesday for GMZ150-155-170-
175.
&&
$$
This product is also available on the web at:
HTTP://WEATHER.GOV/RGV
54
Area Forecast Discussion
National Weather Service State College PA
402 AM EST Tue Nov 29 2016
.SYNOPSIS...
A frontal system will move through the area today. A new wave
will form on the trailing cold front and move through the region
Wednesday. A cooler northwest flow will develop for the end of
the week into the weekend.
&&
.NEAR TERM /THROUGH TONIGHT/...
A plume of deep Gulf of Mexico moisture in advance of potent
shortwave is supporting an expansive area of rain late this
evening from the Grt Lks south thru the Ohio Valley. Regional
radar loop at 03Z shows leading edge of the rain over Eastern
Ohio and HRRR indicates the rain will overspread Central Pa after
midnight. Best forcing from shortwave is progged to track west of
Pa, so expect the area of rain to diminish as it moves into
Central Pa late tonight. Steady or slowly rising temperatures
anticipated overnight under thickening cloud cover and WAA.
Inversion noted in model soundings should keep the wind from
becoming too strong/gusty in the central and eastern counties.
However, model soundings support gusts of 25-30kts across the
higher terrain of the Alleghenies.
&&
.SHORT TERM / WEDNESDAY THROUGH 6 AM WEDNESDAY/...
Low level jet and associated area of rain should have exited the
NW Mtns by dawn. However, a second, shortwave lifting northeast
from the Ohio Valley is expected link up with plume of +2-3SD
PWATS to produce a second batch of heavier rainfall across
southeast Pa between 12Z-18Z. Latest model guidance indicates the rain
could linger into late afternoon across Lancaster Co, but a
general drying trend from west to east is anticipated during the
late AM and afternoon. Model-blended QPF between tonight and
Tuesday ranges from a quarter inch or less across Mckean/Potter
Counties, to near 1 inch across the Lower Susq Valley.
Expect some breaks in the cloud cover by late in the day across
the Laurel Highlands per latest Superblend. However, 00Z NAM and
latest RAP suggest cold air damming and low cigs may persist
elsewhere until early evening. Thus, have lowered max temps
several degrees across the Central Mtns.
It may then be a dismal/damp but mild night Tues night. A wave
develops along the old front over the Deep South while another
front spins off-east of the midwestern storm center. Will keep
chc-low likely pops in for the very last part of Tues night in the
west.
&&
.LONG TERM /WEDNESDAY THROUGH MONDAY/...
The front that is moving through the area today will become nearly
stationary over the central Gulf states today, setting the stage
for a new wave to form under the right entrance region of a
powerful upper level jet streak Wednesday. This new storm will
bring a quick return of surge of moisture for late tonight through
Wednesday with a widespread .50" to .75" of rain expected to fall
over most of the region. We could also see some rare November
thunder as guidance hints at the development of some modest
instability as the storm enters the region. Still too low a
probability to include in the forecast, for now.
The rain will taper to showers Wednesday afternoon as the surface
wave scoots quickly to the southern New England coast by
evening. As the storm pulls away it will set the stage for an
extended period of breezy west-northwest flow. The upstream
airmass doesn`t look especially cold (fairly close to seasonal
normals), but the cold air flowing over the still quite warm lakes
will be enough to provide an extended period of widespread
cloudiness and frequent lake enhanced snow or even rain showers
over the the NW mountains down into the Laurel Highlands, possibly
lasting all weekend.
By Sunday the medium range guidance begins to diverge
significantly with the ECMWF popping an upper ridge through the
NERN US while the GFS/GEFS have a much flatter ridge and keep us
under the WNW flow aloft longer.
Attention then turns to the upper low the models forecast to
develop over BAJA by Saturday. The ECMWF and ECENS take this
eastward and open it up more quickly than the GFS/GEFS which
translates into a new widespread rainfall event Sunday night into
Monday, while the GFS/GEFS don`t bring up the southern stream
energy until Tuesday. This puts the end of the extended forecast
in the very low confidence category.
Temperatures Wednesday will be quite mild, some 15-20 deg above
normal, before falling back to chillier and closer to normal
readings for Thursday into the weekend.
&&
.AVIATION /08Z TUESDAY THROUGH SATURDAY/...
Warm front lifting out of the Ohio Valley will cross central PA
tonight through early Tuesday. Expect lowering CIGs overnight into
tomorrow with a 6-to-9 hour period of rain beginning shortly
after 06z in the west and around 10z in the east. In addition, a
core of strong southerly winds aloft will accompany the rain. The
combination of these winds off the surface and relatively light
wind at ground level will yield widespread LLWS conditions.
Restrictions in the form of low CIGS are expected from about 07z-
18z in many locations, though these could very well linger into
late day over the east as a secondary wave likely keeps precip
going there. Vsby restrictions will also develop overnight, but
will be of shorter duration. LIFR is possible behind the rain in
the low CIGs over the N on Tues aftn/eve.
A brief break in pcpn should occur until the next front moves in
on Wed. Much colder air and prolonged NW flow will follow the
second front.
Outlook...
Tue...Low cigs/rain, mainly in the morning W and all day in the SE.
Wed...Rain/low cigs possible.
Thu-Sat...Sct SHSN w/ocnl IFR in BFD-JST. Isold SHSN AOO-UNV-
IPT. VFR Elsewhere.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SYNOPSIS...La Corte
NEAR TERM...Ceru
SHORT TERM...Ceru
LONG TERM...La Corte
AVIATION...Ceru/RXR
Area Forecast Discussion
National Weather Service Detroit/Pontiac MI
255 AM EST Tue Nov 29 2016
.DISCUSSION...
Dynamically forced convection oriented along the occluded front and
within the corridor of greatest height falls will lift out of the
area to the northeast prior to daybreak. Strong westerly wind field
will provide potential for wind gusts of 40 to 50 mph on an isolated
based on upstream observations so far this morning. Elevated dry
advection surged into the area hours ago and will continue to
descend through the column during the morning. Low-level moisture
axis supporting clouds as far west as Indiana should slowly erode as
clouds work through the southeast half of the CWA and dewpoints fall
into the low 40s by this aftn. Ongoing warm advection pushing 850mb
temps into the mid single digits and better insolation through a
partial coverage of aftn mid-level clouds will support highs in the
mid 50s...perhaps touching 60 in a best case scenario.
Uncertainty increases markedly by Wednesday as the large cyclone to
the west nudges east and an elongated shear max propagating through
the eastern periphery of the trough lifts through the area. Lower
static stability supports potential for deepening low pressure to
foster a blossoming precip shield overhead. SUNY Stony Brook PC
analysis suggests the bulk of variability among the ECMWF ensemble
members is due to intensity outcomes. An ever-so-slightly flatter
00z solution appears to limit PV advection and favor a weaker
solution. This also falls in line with the op GFS and the vast
majority of GEFS members. Although this increases confidence that
Wednesday will not be the washout that some NWP has suggested, there
remains plenty of potential for afternoon shower development. Will
retain the west-east pop gradient on Wednesday but will refrain from
making a call by raising or lowering pops until NWP spread shows
signs of collapsing toward a solution. With no airmass change from
Tuesday, increased clouds and potential for rain suggest max temps
in the low to mid 50s.
Maturing cold conveyor will finally push through the forecast area
Wednesday night as the low is shoved into Quebec by the continued
surge of Pacific jet energy. Moist cyclonic flow and embedded
shortwaves propagating overhead support a chc mention of ra/sn
showers on Thursday, but nothing impactful due to marginal lake
instability and borderline temperatures.
&&
.MARINE...
Ongoing south to southeast gales this morning will ease through the
day as winds become south-southwesterly. Modest southerly breeze
will hold across all marine areas tonight and Wednesday, maintaining
more favorable wind and wave conditions through this time. There
will be a period of stronger southwesterly flow Wednesday night and
Thursday as colder air funnels back into the region. At this time,
gusts are expected to remain below gales.
&&
.PREV DISCUSSION...
Issued at 1158 PM EST Mon Nov 28 2016
AVIATION...
Excruciating mix of VFR to IFR ceilings have existed this evening
with height of widespread precipitation lifting northward through
the cwa. Pockets of moderate rainfall have developed over the past
hour, but back edge of the precipitation and dryslot is already
lifting into the far southern cwa. The NAM remains adamant that
ceiling heights will tank into IFR while the HRRR has backed off
considerably suggesting MVFR. Rolled back mention for
precipitation the remainder of the night based on trends and
shifted to -DZ. Deep, but not particularly strong or active,
subsidence will build into southeastern Michigan for Tuesday.
Potential does exist for some MVFR ceilings with moisture trapped
below inversion, however, clouds Tuesday may be more scattered in
nature.
For DTW...MVFR and IFR conditions have been slow to develop.
With back edge of the rain already lifting into the area, rolled
back the mention and shifted to -DZ. Cold front passage is timed
at DTW around 14Z with a minor change in wind direction from about
190 to 210. VFR cigs to develop by mid morning with return to MVFR
likely Tuesday evening.
//DTW Threshold Probabilities...
* High for ceilings AOB 5000 feet into Tuesday morning.
&&
.DTX WATCHES/WARNINGS/ADVISORIES...
MI...NONE.
Lake Huron...Gale Warning until 4 PM EST this afternoon FOR LHZ363-421-422-441-
462.
Gale Warning until 10 AM EST this morning FOR LHZ361-362-442-443-
463-464.
Lake St Clair...Small Craft Advisory until 10 AM EST this morning FOR LCZ460.
Michigan waters of Lake Erie...Gale Warning until 7 AM EST this morning FOR LEZ444.
&&
$$
DISCUSSION...JVC
MARINE.......MR
AVIATION.....CB
You can obtain your latest National Weather Service forecasts online
at www.weather.gov/detroit.
Area Forecast Discussion
National Weather Service Grand Forks ND
1139 PM CST Mon Nov 28 2016
.UPDATE...
Issued at 1134 PM CST Mon Nov 28 2016
Minimal changes to ongoing forecast.
UPDATE Issued at 935 PM CST Mon Nov 28 2016
Continue to refine pops and precipitation type into the early
morning hours although changes minor. Cando and Devils Lake which
had earlier switched over to light snow have transitioned back to
light rain. This in line with high resolution model guidance which
is dropping warmer air aloft currently over the far northern fa
southward into east central ND by morning. This should limit any
significant accumulations over western fringes of east central
North dakota currently showing best snowfall from regional web
cams.
UPDATE Issued at 633 PM CST Mon Nov 28 2016
Current impulse rotating around upper low impacting mainly the
north half of the forecast area. Most high resolution model
guidance continues to rotate band west and southwest overnight.
May see more mixed rasn this evening over the n-nw however HRRR
warms 925mb temperatures overnight so current thinking of minor
accumulations seems reasonable. Made some pop adjustments to
account for near term radar trends but overall current forecast
on track.
&&
.SHORT TERM...(This evening through Tuesday)
Issued at 328 PM CST Mon Nov 28 2016
Forecast continues on track so overall little change was made.
Upper low drifting a bit west now toward Cooperstown. Radar has
been showing an area of rain on north and west side of the upper
low continuing to move west and northwest with additional rain
spreading north to the east of the upper low attm. So message is
at least into the evening is highest chances for precipitation
eastern ND with a dry slot into the southeastern and eastern fcst
area.
850 mb temps remain a bit above zero north of the upper low into
northeastern ND back toward DVl basin. This warm layer hangs
around tonight then goes away Tuesday. Surface temps continue to
slowly warm a bit into northeastern ND but overall expect not a
big temperature range tonight due to thick clouds and low level
moisture. Temps in area of concern...W of DVL and Cando and
Langdon 33-34F and dont expect any change. It would be a mix of
snow and rain this evening with these bands and with temps as they
are impacts should be minimal. But something to watch closely.
Tuesday will see the moisture being cut off from the upper low and
a transition to more drizzly weather with patches of wet snow.
Temps above freezing so again little impacts anticipated.
.LONG TERM...(Tuesday night through Monday)
Issued at 328 PM CST Mon Nov 28 2016
Tuesday night to next Monday...Overall weather impacts to be
confined to light precipitation mid week and a gradual cooling trend
into the weekend. Highest chances for light snow will be Wednesday
morning with accumulations around an inch possible. Light snow will
mix with rain during the daytime hours limiting accumulations. Upper
low pressure system will finally move enough to the east ending the
potential for measurable precipitation during the day Thursday as
saturation aloft diminishes, read no seeder/feeder mechanism and
less upper level lift. North winds on the backside of the departing
system Thursday will draw a bit cooler air into the northern plains.
As a result the end of the week and into the weekend will be dry
with temperatures ranging from around 30F for highs and teens or low
20s for lows depending on cloud cover.
&&
.AVIATION...(For the 06Z TAFS through 06Z Tuesday night)
Issued at 1134 PM CST Mon Nov 28 2016
CIGs have and will be a big challenge through the period. Along
and east of the valley CIGs showing big variance from IFR to VFR
with mainly IFR west of the valley. Although guidance generally
wants to lower CIGs into IFR range do not have a great deal of
confidence at this point. Did for the most part limit cigs to
MVFR/IFR towards morning and into the day. VSBY at TAF sites
MVFR/VFR and expect these conditions to persist/
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...None.
MN...None.
&&
$$
UPDATE...Voelker
SHORT TERM...Riddle
LONG TERM...JK
AVIATION...Voelker
Area Forecast Discussion
National Weather Service Houston/Galveston TX
1149 PM CST Mon Nov 28 2016
.AVIATION.../06Z TAF/
Surface analysis still shows stationary boundary across SE Texas
mainly between KLVJ and KIAH. South of boundary fog and dense fog
have formed from KHOU to KLBX and KGLS. Visibility has dropped to
1 mile or less in some of these areas and look for fog to expand
into KSGR later this morning. KIAH may not see fog until later in
the morning as the boundary moves north. Low ceilings will be
possible as well. For now think KIAH stays at MVFR CIGS but should
fog and LIFR ceilings advect north with the boundary then CIGS
could be lower for KIAH. Improvement of ceilings/visibility will
be slow through the late morning but think MVFR/VFR CIGS possible
for the afternoon. The next cold front to push through does so
Tuesday night and this should allow for clearing CIGS.
Overpeck
&&
.PREV DISCUSSION... /ISSUED 1143 PM CST Mon Nov 28 2016/
UPDATE...
Now including Harris and Liberty Counties in the dense fog
advisory. The frontal boundary has drifted into southern Harris
County past Hobby Airport and into the southern portion of Liberty
County.
40
PREV DISCUSSION... /ISSUED 1130 PM CST Mon Nov 28 2016/
DISCUSSION...
Including the code in the watch/warning/advisory section at the
end of the page below.
PREV DISCUSSION... /ISSUED 1129 PM CST Mon Nov 28 2016/
UPDATE...
The dense fog has spread into Jackson, Wharton, and Fort Bend
Counties as of 11:15 PM. Will extend the advisory to include
these three counties. Sea fog was also beginning to lower the
visibility to 1 nm and will issue a marine dense fog advisory for
Galveston and Matagorda Bays. All through 14Z/8 AM Tuesday. May
need to extend the advisory in time if necessary.
40
PREV DISCUSSION... /ISSUED 1022 PM CST Mon Nov 28 2016/
UPDATE...
Issued a dense fog advisory for Chambers, Galveston, Brazoria, and
Matagorda Counties for tonight through 8:00 AM Tuesday. Dense fog
was beginning to become widespread at 10:00 PM over portions of
at least Matagorda and Brazoria Counties with some indications
further to the east into Galveston and Chambers.
40
PREV DISCUSSION... /ISSUED 911 PM CST Mon Nov 28 2016/
UPDATE...
At 9:00 PM, the frontal boundary was located across the Houston
area and down near or over the inland portion of the coastal
counties east of highway 59. Am expecting the front to begin to
slowly move back inland during the night or early tomorrow
morning. Sea fog was noted over the Gulf waters. Over the land,
patchy fog was developing on the east side of the front. Dense
fog was already noted at Bay City and dense fog may become more
widespread later tonight between the frontal boundary and the
coast.
Updated forecast weather conditions and temperatures.
40/39
PREV DISCUSSION... /ISSUED 538 PM CST Mon Nov 28 2016/
AVIATION.../00Z TAF/
Upper level trough axis has pushed through but still another jet
streak coming across N Texas tonight. Dryline/Pacific Front has
stalled from KBMT to KLVJ and then down along the coast to KCRP.
Boundary should remain overnight and expected to push north in the
morning. South of boundary calm winds and clear skies will likely
lead to fog and restricted visibility. KHOU/KSGR will be on the
border of this with KLBX/KGLS having fog. KIAH will be watch as
well but concern may be more MVFR ceilings as boundary push north.
HRRR runs at 21/22z both hint at showers in the morning. Will not
put in TAFs yet but may monitor trends and add for 06Z update.
Ceiling should lift through the morning/early afternoon but
depends on how boundary evolves. Boundary should push back south
later in the afternoon with clearing conditions Tuesday night.
39
PREV DISCUSSION... /ISSUED 336 PM CST Mon Nov 28 2016/
DISCUSSION...
A frontal boundary continues to push southeast across the
forecast area this afternoon, stretching from a Livingston to
Tomball to Edna line as of 230 PM CST. Behind this boundary, drier
air has surged into the forecast area with dew points in the upper
30s and low 50s behind the boundary and upper 60s to low 70s ahead
of it. As an associated upper trough oriented almost vertically
across the Great Plains this afternoon continues to lift towards
the Great Lakes, this frontal boundary will continue to push
towards the coast and stall this evening as it loses upper
support.
The approach of this boundary has allowed the pressure gradient
to relax enough to allow the gusty southerly winds observed for
most of the day to subside and veer to the southwest, and expect
only light southerly winds overnight. With clear skies and light
winds overnight, expect patchy to areas of fog to develop within
the vicinity of the stalled frontal boundary (generally south and
southwest of the Houston metro). Have also included a mention for
patchy fog in the nearshore marine areas with warm, moist air
continuing to move across the cooler coastal waters south of the
boundary tonight. Otherwise, expect lows to range in the upper 40s
to mid 50s inland with mid 50s to mid 60s along the coast.
Warm conditions are expected again on Tuesday with highs in the
70s; a few locations west and southwest of Houston may even again
reach 80 degrees. The stalled boundary along the coast will lift
north during the day, possibly lifting to the Houston metro. May
see a few light showers as moisture returns back into the region
behind the boundary, with best chances for rain (20 PoPs) along
and south of the Interstate 59 corridor Tuesday afternoon as a
reinforcing cold front sweeps whatever Gulf moisture pushes back
into the region off the coast.
Drier and cooler conditions are expected behind this second cold
front with highs Wednesday through Friday in the 60s and lows
ranging from the upper 30s to near 60. Moisture begins to return
back to the region on Friday as an upper level system drops into
northwest Mexico from the Gulf of Alaska. Medium range guidance
continues to differ significantly with regards to what impact this
system will have for the region over the upcoming weekend, with
the GFS and Canadian cutting off a low over Mexico and the
European bringing a trough across the state by the end of the
weekend. This would offer vastly different scenarios for timing of
rain for the region, with the GFS/Canadian solutions keeping a
prolonged wet period from late Friday through Monday and the
European resulting in drier conditions almost a full day earlier.
Despite the disagreement on timing, guidance seems to be in
fairly good agreement for the development of a coastal trough with
precipitable water values climbing back above 1.5 inches (with
some guidance showing nearly 2 inches off the coast). This raises
concerns for the potential of heavy rain wherever the coastal
trough sets up and this portion of the forecast (particularly
Saturday and Sunday) will need to be monitored for a heavy rain
threat near the Upper Texas coast.
Huffman
MARINE...
Strong winds aloft mixing to the surface and a tight pressure
gradient will produce strong winds for the remainder of the
afternoon. Winds will drop off this evening in the wake of a weak
Pacific cold front. Elevated seas will remain above 7 feet for the
first half of the night and will maintain a Small Craft Advisory
through the evening hours. The front is forecast to go stationary
over the coastal waters and could wobble back onshore Tuesday
prior to a stronger cold front pushing into the Gulf late Tuesday
night. The return of SCA/SCEC conditions are likely for most of
Wednesday. A moderate east flow will develop on Thursday and is
then progged to strengthen significantly through the rest of the
week in response to a developing coastal trough. Mariners should
prepare for strong winds and elevated seas over the weekend and
another SCA will likely be required. This could produce increasing
tide levels during this timeframe and coastal flooding will be
possible Fri/Sat. 43
&&
.PRELIMINARY POINT TEMPS/POPS...
College Station (CLL) 54 73 46 65 39 / 10 10 10 0 0
Houston (IAH) 58 78 53 67 42 / 10 20 30 10 0
Galveston (GLS) 69 77 62 68 53 / 10 20 40 10 0
&&
.HGX WATCHES/WARNINGS/ADVISORIES...
TX...Dense Fog Advisory until 8 AM CST Tuesday for the following
zones: Brazoria...Chambers...Fort Bend...Galveston...
Harris...Jackson...Liberty...Matagorda...Wharton.
GM...Dense Fog Advisory until 8 AM CST Tuesday for the following
zones: Galveston Bay...Matagorda Bay.
Small Craft Advisory until 4 AM CST Tuesday for the following
zones: Coastal waters from Freeport to the Matagorda Ship
Channel out 20 NM...Coastal waters from High Island to
Freeport out 20 NM...Waters from Freeport to the Matagorda
Ship Channel from 20 to 60 NM...Waters from High Island to
Freeport from 20 to 60 NM.
&&
$$
Discussion...40
Aviation/Marine...39
Area Forecast Discussion
National Weather Service Northern Indiana
353 AM EST Tue Nov 29 2016
.SYNOPSIS...
Issued at 353 AM EST Tue Nov 29 2016
Primarily dry conditions expected during the day today with highs in
the mid to upper 50s. There is a low chance of light rain tonight
through tomorrow. Cooler air will then filter into the region late
Wed through Friday. This could lead to some lake effect rain and
snow showers north of highway 6 but little to no snow accumulation
is expected at this time.
&&
.SHORT TERM...(Today and Tonight)
Issued at 353 AM EST Tue Nov 29 2016
Well-established dry slot/isentropic descent bringing a quick end to
rain this morning. Dry conditions will persist through most of the
day but cloud forecast remains a difficult one. In addition to some
passing mid/high clouds, forecast soundings/RH fields suggest there
could be some lingering low clouds in the morning followed by a
quick return of low level moisture this evening as SW flow/theta-e
advection ramps back up ahead of strong upper jet and shear vort
max. This potentially leaves a somewhat limited window for sun and
mixing. However, based on upstream obs and limited saturation in
morning RAP and HRRR soundings, low clouds should fully erode this
morning with just some passing high clouds. This should give enough
time for adequate mixing to capitalize on warm thermal profiles
aloft before low clouds return. Stayed close to inherited forecast
of mid to upper 50s but could easily bust if low clouds linger or
redevelop sooner. Did expand low chance PoPs for our N/NW counties
this evening though. Several models suggest aforementioned theta-e
surge could be enough to touch off a few iso showers given steep
midlevel lapse rates (500mb temps near -28C in our NW). Could even
be an isolated clap of thunder given modest elevated instability.
Not much support in CAM`s and will be very light/isolated if it does
occur but nevertheless worthy of a low chance mention. Overnight
lows will remain in the 40s with abundant clouds and continued
southerly flow.
&&
.LONG TERM...(Wednesday through Monday)
Issued at 353 AM EST Tue Nov 29 2016
Precip chances linger in our eastern counties on Wed as weak wave
ripples along baroclinic zone to our SE. Deterministic models still
struggling with how far NW adequate moisture will get. Trimmed back
inherited PoPs slightly based on latest trends but still could see a
few light/sct showers along and east of I-69 where low chance PoPs
were retained. CAA doesn`t really ramp up until late Wed so highs
around 50F expected for most locations.
Cool W/NW flow then envelopes the region Wed night through Friday.
Several good chances for lake effect/enhanced precip. The first
arrives Wed night into Thu as a pair of decent shortwaves swing
through the Southern Great Lakes. 0-2km delta theta-e values
approach -1 C/km with abundant/deep synoptic moisture and Lake MI
temps running well above normal (around 10C). Inversion
heights/convective depths also running around 10kft. This should
support a good lake response despite relatively mild airmass (850mb
temps only around -4C). Lack of real cold air (and relatively mild
conditions to date) also lead to a messy precip type forecast. Temps
will likely hover in the 30s with limited diurnal range due to
widespread overcast conditions. Forecast soundings would suggest
that any heavier precip rates would likely fall as snow given very
shallow warm layer. However, ground is still fairly warm (as will be
the roads) and lighter precip will likely fall as rain, especially
during the day Thu. Therefore, chances for any meaningful or
impactful snow accumulation appear low. Biggest impact may just be
reduced visibility in heavier snow showers, similar to first cold
air/lake effect outbreak earlier this month. Another round possible
on Friday, although moisture/instability not quite as favorable
during that time and just low chance PoPs warranted.
First half of the weekend still appears dry. Next large-scale system
approaches early next week but GFS and ECMWF still offering very
different solutions on timing/evolution. Stayed close to consensus
PoPs with plenty of time for adjustments.
&&
.AVIATION...(For the 06Z TAFS through 06Z Tuesday Night)
Issued at 118 AM EST Tue Nov 29 2016
Occluded front will continue across far northeast Indiana over the
next few hours with fairly sharp diminishment in precip as much
drier mid level air overspreads the terminals. Any lingering MVFR
cigs to begin the forecast period should come to an end over the
next hour or two. Gusty southwest winds will gradually diminish
from the 30 to 35 knot gusts...to more in the 20 to 25 ballpark
overnight...continuing to around 20 knots for the remainder of the
day. Another more modest low level moisture transport/convergence
episode is in store late tonight with indications that KSBN would
be more inline for additional low clouds/patchy fog. Confidence is
fairly low in the evolution of low clouds/fog tonight...but
greater impacts appear that would hold off until after this
forecast valid period.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...Gale Warning until 4 AM EST early this morning for LMZ043-046.
&&
$$
SYNOPSIS...AGD
SHORT TERM...AGD
LONG TERM...AGD
AVIATION...Marsili
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Area Forecast Discussion...UPDATED
National Weather Service Mobile AL
1101 PM CST Mon Nov 28 2016
.DISCUSSION...Updated for latest aviation discussion below.
&&
.AVIATION...
06Z issuance...MVFR to IFR cigs and visibilities through 29.14z
followed by mostly MVFR cigs through 29.21z...followed by mostly IFR
cigs and visibilities through 30.06z. Lower cigs and visibilities
mostly in and around showers and maybe a thunderstorm through the
forecast period. gusty southerly winds at 15 to 25 knots with
slightly higher gusts through about 29.09z then gradually diminishing
to 12 to 16 knots through 30.06z. 32/ee
&&
.PREV DISCUSSION... /issued 813 PM CST Mon Nov 28 2016/
DISCUSSION...See updated information for land areas below.
UPDATE...Latest thinking for the next 6 hours suggests persistent
but progressive low level 850 jet now entering western sections of
the forecast area this evening with still very limited cape or
instability near the sfc suggesting convection moving in from the
west remains elevated for most inland areas and will likely do this
through the evening and overnight hours. After looking over some of
the hi res progs both the hrrr and ruc13 still bring in more
convection for this evening still leaving us with some concern though
with the better dynamics lifting off to the ne quickly through 06z
and still the lack of surface based instability we will likely see
more of the same trends on radar through around 2 or 3 am. Worst off
would be a bowing segment with maybe some winds briefly transitioning
to the sfc near the apex of bow. Further south near the coast and
offshore scattered showers with maybe a few thunderstorms mixed in
will become better developed through the night due to the better sfc
based instability over the gulf and possibly near the immediate coast
combined with the forcing aloft. As the better dynamics aloft moves
off to the north the threat for these storms to the south becoming
severe also lessens especially after midnight. With this will begin
to back off on the severe wording for the remainder of tonight...
especially east of the I-65 corridor...though continue monitor
closely. 32/ee
PREV DISCUSSION... /issued 559 PM CST Mon Nov 28 2016/
DISCUSSION...Updated for latest aviation discussion below.
AVIATION...
00Z issuance...VFR to MVFR cigs through 29.03 followed by most MVFR
cigs and visibilities through about 29.09z followed by IFR cigs and
visibilities through about 29.18z then IFR to MVFR cigs through
30.00z. Lower cigs and visibilities mostly in scattered to numerous
showers and thunderstorms moving across the region this evening and
overnight. Winds will continue from the south at 15 to 25 knots with
higher gusts through about 29.09z...diminishing to 10 to 15 kts
through 30.00z. 32/ee
PREV DISCUSSION... /issued 418 PM CST Mon Nov 28 2016/
NEAR TERM /Now Through Tuesday/...A large occluded mid-latitude
cyclone continues to spin on water vapor across the northern plains.
A short wave rotating through the base of the upper trof is
currently generating showers and thudnerstorms over the Arklatex
region where there is an enhanced severe weather risk this afternoon
and evening. Ahead of this system, windy conditions are underway
across much of the southeast with southerly winds of 20 to 30 mph
common, gusting to around 40 mph at times. A wind advisory continues
through 7pm. The Storm Prediction Center maintains a marginal risk
across much of our area with a Slight risk across northwest portions
of the area. As is typical this time of year, the kinematics are
there with 60-70 knots of 0-6km shear and a low-lvl jet increasing
to around 65 knots tonight. The question as it normally is, will be
the thermodynamics. Models agree that a very narrow band of
instability (CAPE) will nudge into the area late this evening and
overnight as a line of showers and storms is expected to develop to
our west and move eastward through the overnight hours.
As far as timing, scattered showers will develop across southeast
Mississippi this evening but are not expected to become severe. A
line of showers and thunderstorms will move into western parts of
the area between 7 pm and 9 pm and into and across southwest Alabama
(to the west of I-65) through around midnight. A few strong to
severe storms are possible along the line. The strong shear will
favor rotating updrafts if a strong enough updraft can develop.
However, we expect the tornado risk to remain extremely isolated
across mainly northwest portions of the area. The most likely event
will be a strongly forced squall line that will weaken as it moves
eastward tonight. Damaging straight line winds will be the primary
threat as it will not take much to mix down the strong winds aloft.
After midnight and through around 4 am or so, expected the weakening
line to continue east of I-65 in interior south central Alabama and
across the western Florida panhandle. Lows tonight will range from
the low 60s across northwest areas to low 70s along the coast.
Scattered rain showers will re-develop on Tuesday with a possible
embedded thunderstorm in the afternoon given continued southwest
flow aloft and potential for reloading instability. We may have to
watch for isolated strong storms Tuesday afternoon if enough
instability develops, however the better chances will be later
Tuesday night. Highs on Tuesday will be in the upper 70s to around
80. 13/JC
SHORT TERM /Tuesday night Through Thursday night/...Some isolated to
scattered showers and storms will continue to be possible Tuesdayevening,
then increased dynamics and omega will begin moving in from the west
around daybreak Wednesday and continue across the forecast area on
during the day. There is the potential for another round of strong to
possibly severe storms, with damaging winds again being the primary
threat. We will continue continue to monitor and fine tune the timing
and potential threats with this second round. Wednesday night through
Thursday night look to be rainfree and cooler as drier high pressure
builds east across the area. Lows tonight ranging from the low 60s
northwest to around 70 coastal tonight and Tuesday night, cooling to
upper 30s west to the low/mid 40s east by Wednesday night in the wake
of the front. Daytime highs in the upper 60s to mid 70s Wednesday and
cooling to the low to mid 60s across entire region on Thursday. 12/DS
LONG TERM /Friday Through Monday/...Rain chances gradually increase
through the long term period with a fairly active upper flow.
Scattered showers and storms expected each day. Remaining a little on
the cool side through the period. Daytime highs in the upper 50s to
upper 60s. Nighttime lows primarily in the 40s. 12/DS
MARINE...Strong southerly winds will continue through Tuesday
morning before decreasing slightly Tuesday afternoon. Winds increase
again Tuesday night into Wednesday as a cold front approaches from
the west. The cold front is expected to move through the marine area
Wednesday afternoon and evening with a moderate northerly flow in
the wake of the front. Small Craft Advisory is in effect for most of
the Marine area through Wednesday. Scattered to locally numerous
showers and thunderstorms can be expected tonight into early Tuesday
and again late Tuesday night into Wednesday. Some of the storms may
be strong to severe. 12/JC
&&
.MOB WATCHES/WARNINGS/ADVISORIES...
AL...High Rip Current Risk through Tuesday afternoon for ALZ265-266.
High Surf Advisory until 6 AM CST Tuesday for ALZ265-266.
FL...High Rip Current Risk through Tuesday afternoon for FLZ202-204-
206.
High Surf Advisory until 6 AM CST Tuesday for FLZ202-204-206.
MS...None.
GM...Small Craft Advisory until noon CST Tuesday for GMZ630>635.
Small Craft Advisory until 6 PM CST Wednesday for GMZ650-655-670-
675.
&&
$$
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http://weather.gov/mob
Area Forecast Discussion
National Weather Service Marquette MI
500 AM EST Tue Nov 29 2016
.SHORT TERM...(Today and tonight)
Issued at 459 AM EST TUE NOV 29 2016
WV imagery and RAP analysis indicated a broad mid/upper level trough
over the Plains with a low centered over the eastern Dakotas. At the
surface, a 983 mb low was located over se ND with an occluded front
extending e through central MN into Upper Mi. Q-vector convergence
and strong moisture advection ahead of a shortwave supported a large
area of rain mainly over central and eastern Upper Mi early this
morning. This area of showers in past hour shrunk in size and is now
confined to the east half of Upper Mi as drier air and q-vector
divergence has moved in in the wake of the shortwave and passage of
occluded front.
Today, with the occluded front continuing to lift north of the area
and q-vector divergence and subsidence taking over, expect mainly
dry weather. Although some weak diurnal instability may allow for
some wrap-around light rain/snow showers to develop over the western
interior. Otherwise, expect breezy southwest winds with temps slowly
falling into the upper 30s west. However, some breaks of sunshine
over the east half will help boost readings into the upper 40s.
Tonight, Dry slot of mid-upper low moving across the area should
ensure dry conditions across much of the forecast area under partly
to mostly cloudy skies. Min temps will range from the low 30s over
interior west to the mid to upper 30s near the Great Lakes.
.LONG TERM...(Wednesday through Monday)
Issued at 440 AM EST TUE NOV 29 2016
Wednesday into Wednesday night: The next shot of energy is progged
to slide near the eastern U.P. early Wednesday morning through
Wednesday evening. The added deep moisture along with increased
forcing, will allow for another chance of showers moving through
mainly the easter half of the U.P. Additionally, the occluded low
will begin to slide across the western U.P. by Wednesday afternoon
and directly over the U.P. Wednesday night, which will begin to
introduce precip chances over the far west in the eveing and the
rest of the U.P again overnight. By that time, cooler air will begin
to move in aloft which may allow some snow to mix in with the rain
at times over the far west late Wednesday afternoon and especially
Wednesday night.
Thursday through the Saturday: The closed low will slowly meander
east of the U.P Thursday through Friday morning before sliding out
of the area by Saturday morning and into the weekend. As this
happens, colder air will continue to filter into the region, at the
surface and aloft, allowing the rain to transition to snow.
Currently it looks like the north to northwest wind favored
snowbelts would be most likely to see the best chances for
precipitation. It does look like temperatures overall will trend
colder during this time period and 850mb temperatures are progged to
cool to the -5C to -8C range for the Thursday through Saturday
morning time period. The temps aloft may cool even more Friday night
into Saturday as a shortwave is progged to slide across the U.P.
This may act to increase the snowfall potential for the area once
again. Snow will be the primary precip type through this time period
during the overnight hours, but a mix of rain is possible along the
shoreline and east during the day.
The rest of the extended: Model solutions begin to take on large
difference, which is not atypical for looking that far out. The EC
brings a fairly strong system up across lower MI, which could have
the potential to bring stronger winds a heavy snow to portions of
the Upper Great Lakes; however, the GFS has no hint of this at all
and actually has high pressure building across the same area. With
all of the major differences will stick with a model consensus for
this time period.
&&
.AVIATION...(For the 06Z TAFS through 06Z Tuesday night)
Issued at 106 AM EST TUE NOV 29 2016
Low level moisture streaming into the region ahead of a deep low
pressure and frontal system will maintain the low clouds into early
Tue. The downslope component with the se to s flow will keep cigs
mainly in the MVFR range at IWD. However, IFR/LIFR cigs are expected
at CMX and especially SAW. Light rain will be overhead much of the
night before diminishing by daybreak on Tue. Could be patchy fog as
well especially at SAW and CMX. Drier air moving into the area
behind the occluded front as winds veer sw will bring improving
conditions by mid Tue morning into early Tue aftn. For the most part
expect MVFR to VFR cigs with no vsby reduction at all the sites into
Tue evening.
&&
.MARINE...(For the 4 AM Lake Superior forecast issuance)
Issued at 459 AM EST TUE NOV 29 2016
Southeast gales in the tight pres gradient ahead of the deep ND low
will gradually shift off to the northeast this morning. The low
pressure system will linger over the Upper Midwest Tuesday into
Wednesday. However the pressure gradient is not expected to be as
tight and should allow winds to diminish below 25kt by Tuesday
afternoon. Northerly winds to around 25 knots may develop Thursday
as the slow moving low moves to the east of Lake Superior into
Quebec.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
Gale Warning until 10 AM EST this morning for LSZ249>251-266-267.
Lake Michigan...
None.
&&
$$
SHORT TERM...Voss
LONG TERM...KEC
AVIATION...JLA
MARINE...Voss
Area Forecast Discussion
National Weather Service Blacksburg VA
434 AM EST Tue Nov 29 2016
.SYNOPSIS...
A series of disturbances emanating from a deep area of low
pressure in the central U.S. will bring at least two rounds of
much needed rainfall to the area through Thursday, one this
morning, and another more significant round Wednesday.
Temperatures through Wednesday will be mild. Drier cooler
conditions will spread back into the area for the end of the week,
although upslope rain and/or snow showers will be possible
Thursday and Friday across the Alleghanys.
&&
.NEAR TERM /THROUGH TONIGHT/...
As of 400 AM EST Tuesday...
First round of much needed rainfall moving through the region
early this morning. This rainfall is associated with a
dampening/shearing out short wave emanating from a deep upper low
centered across the Midwest. Rainfall amounts so far have all been
less than an inch ranging from around 2/3rd or a letter better
across northwest NC into Grayson county VA to only a few hundreths
across the Piedmont. Far from a drought buster, but certainly
welcome, especially with the best rainfall in the most severe
drought Blue Ridge mountain forest areas. The last piece of energy
from this short wave will traverse the region through the morning
hours with additional light rainfall amounts, mostly from this
point forward across the northern and eastern portions of the
forecast area. Additional rainfall during the afternoon/evening
will be limited, but cannot completely drop pops below mentionable
values as broad southwest flow aloft prevails and additional
upstream disturbances are on the way. As the upper low continues
to move slowly east through Wednesday, a more significant and
final disturbance is progged to round the base of the trough and
bring another round of rainfall beginning late tonight in the west
spreading further east Wednesday. With a better tap into the Gulf,
this one promises to bring more beneficial rainfall to the area,
but will leave further discussion on that to the next section.
The GFS is fairly aggressive on instability late tonight/early
Wednesday as the upper-level feature approaches and elevated
thunder cannot be ruled out, but given that this is the only model
indicating such and the potential for a cool, stable boundary
layer, will not include thunder through this period at this time.
The strong surface winds associated with the 50kt+ LLJ will shift
east of the CWA during the morning hours. A few gusts toward 40kts
still not out of the question through the morning hours along the
higher peaks of the Blue Ridge across Bedford/Amherst, but not
enough coverage to warrant a new Wind Advisory. A less impressive
LLJ will approach the region from the west late tonight in
association with the next short wave, but speeds look to be well
below advisory criteria east of the divide and thus will not issue
any further wind headlines at this point.
850mb temps surge well into the double-digit range today of +12C
to +13C well north into the northeast U.S. A non-diurnal
temperature trend was already under way this morning with balmy
late November temperatures in the 50s and which have been rising
overnight. By afternoon this will equate to temperatures well into
the 60s except 50s higher mountain elevations, some 20 degrees
above normal. Look for a very mild night tonight/Wednesday
morning as strong southerly winds continue to transport warm/Gulf
air this direction. Low temperatures Wednesday morning will be
some 30 degrees above normal in the mid 50s to near 60!
&&
.SHORT TERM /WEDNESDAY THROUGH FRIDAY NIGHT/...
As of 200 AM EST Tuesday...
On Wednesday, a shortwave trough will head northeast across the
region on the east side of an upper low/trough centered across the
north central part of the nation. At sunrise, rain is expected across
primarily the western and southwestern portion of the area. As the
day progresses, coverage will translate eastward in concert with a
shift eastward of the upper trough. By Wednesday evening, the
shortwave trough will be exiting the eastern portion of the area
with some trailing precipitation across the eastern quarter of the
area.
The upper systems associated 850mb trough axis will cross the area
Wednesday evening, and northwest flow will commence. Although, the
latest guidance suggests not the best cross barrier flow with an
orientation more west-northwest. Look for scattered rain showers
across the western slopes of southeast West Virginia through the
overnight hours. Enough cold air may arrive by sunrise Thursday for
a mix with or change over to snow showers.
Thursday through Friday night, the upper low/trough near the Great
Lakes region will make gradual progress eastward towards and over
the Canadian Maritimes. This will keep the region under a prevailing
west to northwest flow, all while an west-east oriented surface
ridge axis noses into the western parts of the area. We expected
flurries/sprinkles to conclude the precipitation Thursday morning
across the western parts of Greenbrier County, WV. The vast majority
of the area will be dry Thursday into Friday night. A disturbance
within the northwest flow is expected to pass through NY/PA on
Friday. While most of the energy and moisture with this system will
stay north of the area, enough may make it south enough to yield
scattered upslope flurries/sprinkles across western Greenbrier
County Friday into Friday night.
Temperatures will trend colder during this portion of the forecast.
Readings on Wednesday will be 15 to 20 degrees above normal. By
Friday, temperatures closer to normal for this time of year are
forecast.
&&
.AVIATION /09Z TUESDAY THROUGH SATURDAY/...
As of 1145 PM EST Monday...
Ceilings had continued to drop throughout the evening and were now
MVFR along and west of the Blue Ridge. ceilings will continue to
lower overnight with KLYH and KDAN becoming MVFR shortly after
06Z/1AM. High confidence of IFR to LIFR ceilings over the
mountains by 12Z/7AM.
A bigger concern is the low level jet ahead of the front with a
core in excess of 70kts. The main thrust of the jet will brush
southwest Virginia as it rides up west of the Appalachains, but
the overall wind field is broad and there will be a sharp increase
in in low level winds overnight. Have increased surface wind gusts
at KBLF and have LLWS at KLWB, KDAN and KBCB early tonight.
Believe once precipitation sets in and lapse rates become less
steep this will act to limit downward momentum transfer so will
indicate higher winds before onset of precipitation. Based on the
HRRR and other HiRes models have slowed down arrival time of
shower east of the Blue Ridge, with showers reaching KLYH and
KDAN around 10Z/4AM. This may create an opportunity for gusty
winds at KROA, KLYH and KDAN ahead of the showers. Medium
confidence on the winds tonight.
With a lot of flow parallel to the front, it will be in no hurry
to clear the region and may well end up stalling out in our
vicinity. This will allow poor flight conditions to linger into
Tuesday evening, though winds will be lessening as the core of
stronger winds aloft pulls off to the north. Medium confidence on
any improvement in the ceilings, especially in the mountains.
Extended aviation discussion...
A more significant batch of rain arrives later Tuesday night and
continues into Wednesday evening. This likely to keep widespread
sub-VFR ceilings and visibilities in place until the cold front
passes through the region early Thursday.
Drier air behind the front should result in a return to VFR east
of the mountains Thursday while upslope sub-VFR cigs likely
linger across the southeast West Va locations, where rain or snow
showers appear possible. Broad northwest flow looks to keep this
scenario in place on Friday. Showers will dissipate for Friday
night and Saturday but clouds will linger over the mountains.
&&
.Fire Weather...
As of 430 AM EST Tuesday...
Beneficial rainfall of 1/2 to isolated near 1 inch amounts
observed across the southwest part of the forecast area, which has
been the driest area with the most significant drought and forest
fire conditions in recent weeks. Thus, this rainfall is very good
news. Now with winds also in a diminishing trend, fire threat has
been greatly reduced. Additional rainfall expected
tonight/Wednesday should further alleviate any fire weather
concerns in the short term.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...Wind Advisory until 7 AM EST this morning for VAZ007-009-015.
NC...Wind Advisory until 7 AM EST this morning for NCZ001-018.
WV...Wind Advisory until 7 AM EST this morning for WVZ042.
&&
$$
SYNOPSIS...RAB
NEAR TERM...RAB
SHORT TERM...DS
LONG TERM...DS/PC/RAB
AVIATION...AMS/MBS
FIRE WEATHER...RAB
Area Forecast Discussion
National Weather Service Tampa Bay Ruskin FL
308 AM EST Tue Nov 29 2016
.SYNOPSIS...
08Z water vapor and H4 RAP analysis shows a highly amplified upper
level pattern has evolved over the CONUS. The main player in the
synoptic pattern is longwave troughing extending form the inter-
mountain west through the entire mid-section of the country and
currently extending as far east as the Appalachians. The trough
has amplified bookend ridges over both the Pacific and Atlantic
seaboards. This large trough is anchored by a large cut- off low
spinning over the Dakotas/Minnesota. This large system has been
responsible for all kinds of inclement weather over the past 24
hours...from heavy snows in the north to severe weather in the MS
Valley. While one severe weather event is ending across the deep
south...another strong lobe of energy is poised to round the
bottom of the trough through the southern Plains/lower MS valley
later today and tonight...bringing another potential round of
severe thunderstorms to that region. We here in Florida remain
simply bystanders to all the inclement weather...as our region
remains within a much more benign pattern underneath deep layer
ridging. This ridging will continue to protect our region through
Wednesday...with generally dry and warm conditions.
At the surface...
Florida peninsula and eastern Gulf of Mexico resides within a
deep southeast to south flow pattern between a slow moving cold
front through the deep south...and sprawling high pressure over
the western Atlantic. Generally speaking...this synoptic pattern
will not change much of the next 24 hours. The continued southern
component to the low level flow will bring further increases with
respect to low level moisture. Temperatures early this morning
are very warm for the end of November...with most spots not
falling out of the 60s.
&&
.SHORT TERM (Today through Wednesday)...
Stacked ridging and a warm boundary layer will provide a mostly
dry day with well above normal temperatures. Temperatures will be
starting from a warm point...so given the expected efficient
diurnal mixing and insolation today...would expect most spots away
from the immediate coast to rise into the 80s this afternoon. The
immediate coast will be a bit more tricky in terms of temperatures
after about 18Z. Strong terrestrial heating should be sufficient
to turn winds a bit onshore at the immediate coast. This partial
flow off the cooler shelf waters should at least stop the diurnal
temperature rise...keeping temps in the 70s...or drop temps back
into the 70s for the majority of the afternoon. However...will not
have to go more than a couple miles inland to get right back into
the 80s.
The low level moisture is high...but its shallow. Borderline
conditions with the onshore convergence component to support a few
isolated shower along the I-75 corridor during the late
afternoon/early evening. A few convective allowing NWP members
support this...as does the NAM. Given the low level instability
potential...will add a few sprinkles/light showers to the forecast
after 20Z. Similar to Monday...most spots...even if they do see a
shower...with not even measure.
Another very warm night for the end of November coming up...as
southerly flow and low level moisture keeps low temperatures from
falling out of the lower/middle 60s. The gradient looks as though
it might be a bit weaker by the second half of tonight...and that
weaker BL mixing is likely to provide improved conditions for fog
formation during the late night hours. Have added areas of fog to
the grids away from the immediate coast...and will let the
dayshift re-evaluate the SREF/NARRE guidance for dense fog
potential updates for the next forecast cycle.
Wednesday...More of the same for the daylight hours. Very warm and
mostly dry conditions will prevail for the majority of the day. We
will be watching a cold front slowly approach from the west across
the FL panhandle during the afternoon...with the mid/upper level
flow turning gradually more cyclonic over our northern Nature
Coast zones. However...the best synoptic forcing for deep ascent
is quickly lifting away from the northern Gulf coast by the end of
the day...and there is very good agreement among the reliable
guidance members that the low level convergent forcing and
moisture flux convergence along and ahead of the front will be
declining quickly after 18Z. Therefore...if this progs are
correct...we are likely only looking at a broken and decaying band
of narrow showers approaching Levy/Citrus county late in the
afternoon or evening. Allowed for a 20% PoP for Levy county after
21Z...but left rain mention out of remaining Nature Coast zones
for now...especially before dark.
&&
.LONG TERM (Thursday through next Tuesday)...
The highly amplified pattern that we`ve seen over the past several
days will flatten out over the long term period. A closed upper low
sits over the western Great Lakes region with significant troughing
extending south through the central U.S. A little closer to home, an
upper level high sits over the Bahamas with ridging extending
southwest to northeast over the western Atlantic. This ridge will
slip eastward as the trough and upper low move northeast toward
Ontario by Thursday morning. By Friday night, the upper low has
moved over Nova Scotia and the upper ridge has flattened out over
the Caribbean. This zonal pattern will continue until late Monday
night when strong ridging builds back into the southeast U.S.
On the surface, ridging extends west southwest from a high pressure
center located near Bermuda. But, the main surface feature for the
eastern U.S. is a frontal boundary extending south along the
Appalachian Mountain chain from a low over the eastern Great Lakes.
Most of the dynamics of this low pressure system will remain well to
the north of Florida, but will still bring our highest chances of
rain through the period. We can expect 20-40 POPs over the northern
coastal waters and Nature Coast beginning late Wednesday with
coverage sinking south to Manatee County by Thursday morning. The
southern portion of the CWA should remain dry as the front moves
through. The front pushes south by Thursday evening, as high
pressure over the northern Gulf coast moves into the area bringing
clearing conditions through Saturday.
Models are in good agreement through late Saturday. At that time
they begin to diverge a bit with ECMWF developing a stronger low and
frontal boundary over southeast Texas and moving it up the Gulf
coast. GFS is hinting at a disturbance, but keeps it much weaker.
So, went with the more aggressive solution bringing 30-50 POPs into
the area on Sunday into early Monday. High pressure builds back in
on Tuesday once again bringing clearing conditions. Daytime highs
will be at or above normal on Thursday, then dropping down 3-5
degrees below normal on Friday, then warming back up once again to
average on Saturday and Sunday. With the passing of the frontal
boundary on Monday, temps will once again drop 3-6 degrees below
average through the middle of next week.
&&
.AVIATION (29/08Z through 30/06Z)... Uncertainly in degree of
potential cig restrictions across the region this AM. Gradient
winds remain elevated enough to prevent significant fog...but
statistic guidance aggressive with IFR/MVFR cigs after
09Z...especially north of KPGD. Given degree of low level
moisture...can not rule out this scenario...and opted to go with
MVFR prevailing CIGS from KPGD north to the Tampa Bay area. Will
monitor trends closely and update as needed. Beyond 14Z...general
VFR conditions should be the rule through the remainder of
Tuesday...although winds become gusty over 15 knots at times from
the southeast and south.
&&
.MARINE...
Flow will be from the southeast and south through Wednesday
between a slowly approaching front to our northwest and a large
region of Atlantic high pressure to our northeast. Winds over the
eastern Gulf of Mexico will be elevated at times...with cautionary
level winds ongoing this morning away from the immediate coast.
Winds are expected to briefly decrease this afternoon...but will
return to cautionary levels over the offshore waters tonight into
much of the day Wednesday. A cold front will shift south across
the forecast waters on Thursday...turning winds out of the north
and northeast. Another period of cautionary level winds from the
north will be possible behind this front during Thursday night and
Friday.
&&
.FIRE WEATHER...
No significant fire weather concerns through at least Thursday.
Low level moisture will continue to increase today and prevent any
critical levels of relative humidity from being reached. The
elevated moisture will linger through Wednesday. Only concern for
today will be the development of gusty southeast to south winds
during the later morning and afternoon hours. A cold front will
slip south through the region during Thursday. This front will
introduce a cooler and drier airmass to the region...however not
enough dry air is expected to arrive before sunset on Thursday to
cause any real fire weather hazards.
Fog Potential...
No significant fog concerns expected this morning. Increasing
potential for some areas of fog (possibly dense) after midnight
tonight into early Wednesday morning.
&&
.Preliminary Point Temps/PoPs...
TPA 81 67 81 69 / 10 10 10 20
FMY 83 66 83 67 / 10 10 0 10
GIF 83 65 85 66 / 10 10 0 0
SRQ 78 67 82 67 / 10 10 10 10
BKV 82 63 83 65 / 0 10 10 20
SPG 80 67 81 69 / 10 10 10 20
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...Beach Hazards Statement through Thursday evening for
Coastal Sarasota.
Gulf waters...None.
&&
$$
SYNOPSIS/SHORT TERM/AVIATION/MARINE/FIRE WX...Mroczka
MID TERM/LONG TERM/DECISION SUPPORT...Wynn
Area Forecast Discussion
National Weather Service Las Vegas NV
836 PM PST Mon Nov 28 2016
.SYNOPSIS...A dry northwest flow will develop over the region
through much of the week with continued cool temperatures and
occasional shots of north wind.
&&
.UPDATE...Winds diminished across Esmeralda, central Nye and western
San Bernardino counties early this evening and the wind advisories
were allowed to expire at 7 PM. Winds dropped below 10 mph across
much of the Las Vegas Valley early this evening and it appears that
gust of 20-25 mph will hold off until after sunrise Tuesday...except
maybe for the northwest part which could kick back up late tonight.
Wind grids were adjust downward based on the latest HRRR wind
forecast.
The main concern now is the potential for the first freeze over much
of central and northeast Clark counties, including the Las Vegas
Valley early Wednesday morning. The 00Z NAM MOS guidance has 34
degrees for McCarran and 31 degrees at Nellis AFB and Henderson
Executive airport. The 12Z ECMWF MOS also has 31-32 degrees for
Henderson and Nellis. Obviously it will not be a hard freeze, but
the setup is right for much of the area outside of the central
valley to see a first freeze. Nellis already touched 32 degrees a
couple times last week, but this will be more widespread. Also, the
latest GFS COOP MOS guidance output indicates temperatures across
the San Bernardino County desert zones look favorable for a first
freeze including Baker, Barstow and Yucca Valley and Morongo Basin.
They will be included also.
&&
.PREV DISCUSSION...
239 PM PST Mon Nov 28 2016
.SHORT TERM...through Wednesday night.
Another gusty day across the western Mojave Desert as well as
Esmeralda and central Nye Counties. Wind Advisories in those
specific areas runs through 7 pm this evening.
A cold front currently across southern Lincoln County will push
south through Clark County over the next 3 hours and eventually the
entire Mojave Desert by late evening. Gusty northwest winds will
develop behind the front and persist through the day Tuesday.
Some light snow showers will accompany the cold front through
northern Mohave County early this evening. Otherwise the region will
be dry as a weak ridge develops across the region through Wednesday.
.LONG TERM...Thursday through Sunday.
The main concern in the long term is an upper level low diving south
across the region Thursday and Friday. While it may still have a
little moisture to work with in extreme northern portions of the
area, the track does not favor precipitation across most of the CWA.
Kept slight chances in the terrain of Esmeralda county and the
Lincoln County panhandle, with chances in Mohave county as the
system continues south. There are still significant differences in
the models, but the general consensus seems to dig the low into
Arizona by Friday. The models diverge quite a bit after that, though
the solutions have similar sensible weather for the region with
ridging beginning to influence the region, helping to warm temps a
few degrees closer to normal.
&&
.AVIATION...For McCarran...North winds will persist overnight
then strengthen early Tuesday morning with gusts of 20-22 knots
through at least early afternoon. Winds will become light south-
southwest Tuesday evening.
For the rest of southern Nevada...northwest Arizona...and southeast
California...Gusty northwest to north winds will persist across the
entire Mojave Desert overnight and through Tuesday. Generally wind
gusts will be 20-25 kts except within the Colorado River Tuesday
where winds may gust to 30 kts.
&&
Update/Aviation...Adair
Short Term...Pierce
Long Term...Steele
For more forecast information...see us on our webpage:
http://weather.gov/lasvegas or follow us on Facebook and Twitter
Area Forecast Discussion
National Weather Service Columbia SC
637 AM EST Tue Nov 29 2016
.SYNOPSIS...
A diffuse front will remain in the forecast area through tonight.
A cold front approaching Wednesday will move through the forecast
area Wednesday evening. Breezy conditions will be associated with
these fronts. Much above normal temperatures will lower behind the
cold front over the weekend.
&&
.NEAR TERM /THROUGH TONIGHT/...
Believe the main forecast issue today will be wind. The KCAE 88D
VAD confirms the low-level jet has overspread the area. The NAM
and GFS depict h85 wind 40 to 50 knots today. The NAM displays
surface-based LI values 0 to -1. Therefore, some of this wind
should mix down to the surface. Based on the GFS LAMP and average
wind in the mixed layer shown by the NAM bufkit expect gusts 25 to
30 knots today with the greater gusts during the afternoon
associated with greater heating and mixing. A lake wind advisory
is needed. The models depict the h85 jet diminishing somewhat
and with diminished mixing associated with nocturnal cooling
expect below lake wind advisory criteria wind tonight.
The h85 jet plus some upper lift associated with the tail end of
the mid-level shortwave trough will help support showers today.
Water vapor imagery trends and the models suggest the upper lift
will diminish today. The HRRR indicates diminishing shower
coverage. Based on radar trends forecasted the highest pops in the
northwest section. Expect mainly showers instead of thunderstorms
because of the weak forcing but did keep isolated thunderstorms in
the forecast near the time of maximum heating today.
The temperature guidance was close today. Highs should be about 15
degrees above normal for late November. Followed the higher
minimum temperature guidance tonight because of mixing and
cloudiness.
&&
.SHORT TERM /WEDNESDAY THROUGH WEDNESDAY NIGHT/...
The models are close depicting the approaching cold front moving
through the forecast area Wednesday evening. Much of the upper-
lift associated with a dampening shortwave trough should hold off
until Wednesday night. Isentropic lift supports a chance of
showers early Wednesday with the chance increasing late in the day
associated with convergence near the front. The ARW displays a
weakening line of showers crossing the forecast area during the
late afternoon and evening. Shear will remain strong. The NAM and
GFS indicate h85 wind near 50 knots. The severe thunderstorm
threat should be limited by weak instability. The NAM displays
surface-based LI values around -1. However, instability could
become a little greater because of the favorable diurnal timing
just ahead of the cold front. Any thunderstorms could possibly
contain damaging wind because of the strong shear. The NAM and GFS
were close with rainfall amounts. The ECMWF had amounts a little
greater. Followed a guidance consensus which was close to the SREF
mean. Expect amounts mainly 0.2 to 0.5 of an inch.
It also will be generally windy ahead and along the front. The
NAM bufkit momentum transfer tool supports gusts 25 to 30 knots
and believe another lake wind advisory will be required.
Followed the guidance consensus for the maximum temperature
forecast. Mixing associated with the front favors the higher
minimum temperature guidance.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
Cool and dry weather is expected behind the front Thursday
through Saturday. The GFS and ECMWF indicate surface ridging
moving into the area with near zonal flow. The upper flow may back
ahead of the next system by Sunday or Monday. The models indicate
considerable moisture and isentropic lift. The GFS and ECMWF MOS
have pops 40 to 60 percent Sunday and Monday. The models
indicate near normal temperatures through the medium-range
period.
&&
.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
High pressure to our east, and a weak front to our west, will
provide a general southerly low-level flow, with gradually
increasing winds through this afternoon, and LLWS this morning.
Latest CAE VWP showing 40 kt at 2000 ft. The front to our west is
expected to slow down as it approaches our area due to flow aloft
becoming SW nearly parallel to it, and associated convective
activity along it is expected to decrease as it enters less moist
and unstable air and as best upper support pulls away to the
north. Ahead of the approaching front, weak isentropic lift, and
gradually increasing moisture, will provide a few light showers
and MVFR CIG restrictions affecting our terminals mainly this
morning. Latest composite radar showing bulk of precipitation is
over portions of the Upstate and northern GA and short-range hi-
res guidance indicating much of this precipitation will remain
west of the TAF sites this morning, although cannot rule out a few
light showers. Guidance also indicating possibility of MVFR CIGS
developing again late tonight. Breezy conditions today with gusts
to around 25 kts, but winds should diminish by this evening.
EXTENDED AVIATION OUTLOOK...Expect breezy conditions to continue
through Thursday. IFR to MVFR restrictions at times Tuesday night
through Thursday, with best chance of showers, and a possible
thunderstorm, Wednesday night into early Thursday morning.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
GA...Lake Wind Advisory until 5 PM EST this afternoon for GAZ040-
063>065-077.
SC...Lake Wind Advisory until 5 PM EST this afternoon for SCZ015-
016-018-020>022-025>031-035>038-041.
&&
$$
Area Forecast Discussion
National Weather Service Caribou ME
954 AM EST Tue Nov 29 2016
.SYNOPSIS...
Low pressure will track across the region Tonight into Wednesday.
Another area of low pressure will move through Wednesday night
into Thursday.
&&
.NEAR TERM /THROUGH TONIGHT/...
952 am update...
Hrly temps were brought in line to fit the current conditions.
Satl imagery showed clouds moving steadily ene. The NAM and GFS
did not pick up on the llvl cold air near the blyr this morning.
The RAP did much better and decided on following its profile
through the afternoon which shows warming into northern areas.
This will pose a problem to precip type later on. For now, adjusted
the ice potential to edge it further n toward MLT-HUL and GNR
region. QPF amounts may need adjustment as well. This will be
addressed later on.
Prev discussion blo...
Once pcpn mvs in it wl quickly ovrsprd region as warm advection
spills acrs the state with 35-50kt llj punching in fm the sw.
Latest GFS initialized aloft too warm by a degree or two acrs the
Plains whereas NAM was closer to reality. Therefore am leaning
more twd cooler NAM wrt ptype for tda with a little wiggle room
for GFS soln.
NAM BUFKIT sndgs show all snow from HUL to Clayton Lake line north
thru the entire event, though may see some sleet briefly mix in
at times along this line. Along a MLT-GNR line expect snow to
start approx 20z with perhaps a snow, sleet or rain mix aft 06z
depending on sfc temps. Aft 06z, begin to see drying in the
dendrite zone but it is possible seeder-feeder mechanism wl kick
in to add ice crystals fm aloft. If not, expect that rain/fzra may
occur thru daybreak bfr pcpn winds down. Further south, the cooler
NAM is showing all liquid south of Bangor down to the coast
therefore hv opted not to expand advisory further south.
Storm total snow is similar to what prior shift issued with 6-8
inches acrs nrn zones with perhaps a slight nudge to the south by
approx 20 miles or so. May see a trace of frzg rain at some point
drg the night as warm air works in aloft, hwvr sndgs are
indicating vry little in the way of a warm lyr and warming
isothermally down to the sfc.
&&
.SHORT TERM /WEDNESDAY THROUGH THURSDAY/...
Low pressure is expected to move eastward out of the Gulf of
Maine Wednesday Morning as weak high pressure builds across the
state. Another area of low pressure will approach from the west
Wednesday evening. This system is expected to redevelop in the
gulf of Maine late Wednesday Night into Thursday. The new low will
move off to the northeast into the Maritimes late in the day
Thursday. Since warmer air is forced in ahead of this system as it
approaches from the west, significant snow will be confined to
northern and northwestern areas on Thursday. Will use a blend of
the GFS, ECMWF, and NAM for all girds. Snow amounts from snow
ratios and QPF amounts.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
The low pressure system will continue to move away to the
Northeast Thursday Night into the weekend but cyclonic
circulation behind the low will cause snow and rain showers to
persist across the region into the weekend. Strong high pressure
is then expected to build in from the west Sunday into Monday. The
high is then expected to crest over the region Tuesday.
&&
.AVIATION /15Z TUESDAY THROUGH SATURDAY/...
NEAR TERM: IFR at FVE through 15z this morning as low-level
stratus remains. Expect cigs to rise to MVFR by this time. MVFR
stratus has dissipated at CAR, PQI and HUL with MVFR expected to
move in by 21z this afternoon. MVFR restrictions expected at BGR
and BHB between 19z and 22z in -ra (BHB) and -rasn (BGR). Expect
all terminals to be IFR tonight through end of TAF valid time.
SHORT TERM: IFR/MVFR conditions are expected Wednesday and
Thursday. MVFR/VFR conditions are expected Friday and Saturday.
&&
.MARINE...
NEAR TERM: Winds will gust abv 25kts this aftn as seas come up abv
5ft in srly swell. SCA for intracoastal this aftn with Gale
Warning for outer waters fm 00z to 07z tonight with winds gusting
ovr 35kts. Will likely need to re-issue SCA for outer waters once
winds diminish blo gale levels.
SHORT TERM: Will use a blend of the GFS, NAM, and ECMWF for
sustained winds: For waves: A southerly fetch develops from the
Gulf of Maine southward early Wednesday with waves building to 4-5
feet/9 seconds. This will be accompanied by a secondary
northeasterly wind wave across the gulf of Maine Thursday as a
northeasterly flow develops. Will use the Near Shore Wave Model
to populate wave grids.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...Winter Weather Advisory from 2 PM this afternoon to 4 AM EST
Wednesday for MEZ002-005-006.
Winter Weather Advisory until 4 AM EST Wednesday for MEZ001-
003-004-010.
Winter Weather Advisory from 3 PM this afternoon to 4 AM EST
Wednesday for MEZ011-031-032.
MARINE...Small Craft Advisory from 5 PM this afternoon to 7 AM EST
Wednesday for ANZ052.
Gale Warning from 7 PM this evening to 2 AM EST Wednesday for
ANZ050-051.
&&
$$
Near Term...Farrar/Hewitt
Short Term...Mignone
Long Term...Mignone
Aviation...Farrar/Hewitt/Mignone
Marine...Farrar/Hewitt/Mignone
Area Forecast Discussion
National Weather Service State College PA
729 AM EST Tue Nov 29 2016
.SYNOPSIS...
A frontal system will move through the area today. A new wave
will form on the trailing cold front and move through the region
Wednesday. A cooler northwest flow will develop for the end of
the week into the weekend.
&&
.NEAR TERM /THROUGH TONIGHT/...
A plume of deep Gulf of Mexico moisture in advance of potent
shortwave is supporting an expansive area of rain late this
evening from the Grt Lks south thru the Ohio Valley. Regional
radar loop at 11Z shows rain through central PA and HRRR
indicates the rain will continue to move through Central Pa this
morning. Expect the area of rain to diminish as it moves into
eastward and breaks in the precipitation should occur this
afternoon. Steady or slowly rising temperatures anticipated
today under thickening cloud cover and WAA.
The inversion noted in model soundings should keep the winds from
becoming too strong/gusty in the central and eastern counties.
However, model soundings support gusts of 25-30kts across the
higher terrain of the Alleghenies.
a second, shortwave lifting northeast from the Ohio Valley is
expected link up with plume of +2-3SD PWATS to produce a second
batch of heavier rainfall across southeast Pa between 12Z-18Z.
Latest model guidance indicates the rain could linger into late
afternoon across Lancaster Co, but a general drying trend from
west to east is anticipated during the late AM and afternoon.
Model-blended QPF between tonight and Tuesday ranges from a
quarter inch or less across Mckean/Potter Counties, to around
three quarters of an inch through the lower Susquehanna valley.
The
WAA will allow for highs today in the upper 50s. These forecasted
highs are 10 to 15 degrees above normal.
It may then be a dismal/damp but mild night Tuesday night. A wave
develops along the old front over the Deep South while another
front spins off-east of the midwestern storm center. Will keep
chc-low likely pops in for the very last part of Tues night in the
west.
&&
.SHORT TERM /WEDNESDAY/...
The front that is moving through the area today will become nearly
stationary over the central Gulf states today, setting the stage
for a new wave to form under the right entrance region of a
powerful upper level jet streak Wednesday. This new storm will
bring a quick return of surge of moisture for late tonight through
Wednesday with a widespread .50" to .75" of rain expected to fall
over most of the region. We could also see some rare November
thunder as guidance hints at the development of some modest
instability as the storm enters the region. Still too low a
probability to include in the forecast, for now.
The rain will taper to showers Wednesday afternoon as the surface
wave scoots quickly to the southern New England coast by
evening.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH MONDAY/...
As the storm pulls away it will set the stage for an extended
period of breezy west-northwest flow. The upstream airmass doesn`t
look especially cold (fairly close to seasonal normals), but the
cold air flowing over the still quite warm lakes will be enough to
provide an extended period of widespread cloudiness and frequent
lake enhanced snow or even rain showers over the the NW mountains
down into the Laurel Highlands, possibly lasting all weekend.
By Sunday the medium range guidance begins to diverge
significantly with the ECMWF popping an upper ridge through the
NERN US while the GFS/GEFS have a much flatter ridge and keep us
under the WNW flow aloft longer.
Attention then turns to the upper low the models forecast to
develop over BAJA by Saturday. The ECMWF and ECENS take this
eastward and open it up more quickly than the GFS/GEFS which
translates into a new widespread rainfall event Sunday night into
Monday, while the GFS/GEFS don`t bring up the southern stream
energy until Tuesday. This puts the end of the extended forecast
in the very low confidence category.
Temperatures Wednesday will be quite mild, some 15-20 deg above
normal, before falling back to chillier and closer to normal
readings for Thursday into the weekend.
&&
.AVIATION /12Z TUESDAY THROUGH SATURDAY/...
Warm front lifting out of the Ohio Valley will cross central PA
this morning. Restrictions in the form of low CIGS are expected
through 21z across the western and central TAF sites. BFD, JST and
AOO are IFR and lower with MVFR elsewhere. Expect these low cigs
to continue through early afternoon. As the front passes through
MDT and LNS they should drop to IFR between 12Z to 15Z. A brief
break in pcpn should occur later this afternoon, after 20Z, until
the next front moves in on Wednesday. Much colder air and
prolonged NW flow will follow the second front.
Outlook...
Tue...Low cigs/rain, mainly in the morning W and all day in the SE.
Wed...Rain/low cigs possible.
Thu-Sat...Sct SHSN w/ocnl IFR in BFD-JST. Isold SHSN AOO-UNV-
IPT. VFR Elsewhere.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SYNOPSIS...La Corte
NEAR TERM...Ceru
SHORT TERM...Ceru
LONG TERM...La Corte
AVIATION...Ceru/RXR
Area Forecast Discussion
National Weather Service Grand Forks ND
936 AM CST Tue Nov 29 2016
.UPDATE...
Issued at 928 AM CST Tue Nov 29 2016
Forecast in overall good shape with a burst of snow ongoing in the
far west from Devils Lake to Cando sliding to the southwest.
Another band of precipitation, mainly light rain or drizzle, is
stretched from Lake of the Woods to Bemidji back to the southwest
through Thief River Falls and Crookston into the Fargo area.
Temperature profiles continue to show liquid precipitation for all
but the far west where snow is the dominant ptype.
UPDATE Issued at 635 AM CST Tue Nov 29 2016
Morning update focuses on precip coverage. Receiving reports of
precip at Baudette and Bemidji where radar is showing no returns
so have forced 88D into higher power mode to improve return
coverage. In general, HRRR has the best handle on current trends
this morning although struggling with band over west central MN.
Have adjust POPs with blend of HRRR and prev forecast...keeping
most of w central MN dry or low POPS thorugh mid morning. Surface
low beginning to move into w central MN and should begin to pull
cooler air over central ND into the Devils Lake basin, changing
rain to a rain-snow mix. No changes for timing of transition over
to snow east of Devils Lake.
&&
.SHORT TERM...(Today and tonight)
Issued at 334 AM CST Tue Nov 29 2016
The forecast challenge for the short term period continues to be
precipitation type, rainfall/snowfall amount and temperatures. The
majority of eastern North Dakota into the Red River Valley is
ranging from 34 to 36 degrees...with temps around the 40 mark in
the northern valley. The latest surface obs indicate the surface
low in the vicinity of Wahpeton with trough extending through
Otter Tail county and into Crow Wing county MN. The low has begun
to gradually drift to the east and should take a southeast
trajectory to near Alexandria by mid afternoon...although the NAM
is a bit further to the northeast with the upper vort over
northeastern ND. Warm air advection from the NE has brought
surface temps across Devils Lake into the mid 30s and precip
changed over to snow last evening, with most recent web cams
showing at least some melting of the snow they received yesterday
morning. Snow is being reported at Valley City with rain likely
now at Cooperstown...and the rain-snow line appearing to be along
a line from Valley City possibly into the Rugby area. The main
batch of precip moving northeast out of northeastern ND is moving
into the Griggs/Eddy/Nelson county region and is rain or a
rain/snow mix.
As the surface low begins to accelerate east, precip over central
ND as well as a slightly cooler near surface layer will help
change rain back over to snow in the far western regions into
portions of southeastern ND, but the southeast will quickly return
to rain while a wintry mix is not expected to move into the valley
until near sunset. This slow transition will limit the best
snowfall accumulations once again to about the Highway 281
corridor and west, where a second round of 1 to 3 inches is
possible by 00Z Wednesday. As the surface low pulls east, the
tighter pressure gradient over central ND as well as stronger cold
advection into the low pull cause some gustier winds but snow will
be wet enough that blowing/drifting snow will not be an issue. The
surface low moves into northwestern WI by 12Z Wednesday. Most
regions will receive up to one quarter of an inch of rainfall
with higher amounts across the south and west. Only minor
accumulations are expected west of a Devils Lake to Valley City
line by morning as surface temperatures stay in the mid 30s.
.LONG TERM...(Wednesday through Monday)
Issued at 334 AM CST Tue Nov 29 2016
Models are indicating a shallow saturated level being overrun by
dry air aloft Wednesday afternoon. The GFS keeps the top of the
saturated level near the ice crystallization level, however
blended solutions dry that layer out. Light snow is expected to
continue through noon Wednesday, with only minor accumulations,
however if the lower layers of the atmosphere do not dry out and
end precip, there is a chance for drizzle or freezing drizzle
expanding north to south during the afternoon hours. Only minor
accumulations of ice are possible...mainly on untreated roads
however the warm road temperatures will make accumulation
difficult. Grids indicate drizzle or light snow with some
uncertainty in the depth of the shallow saturated layer.
Lingering isolated snow showers will continue into Thursday
morning with thinning clouds during the afternoon hours, however
temps are expected to stay around freezing throughout the day. A
much colder and drier air mass will move over the area Thursday
night and temps may fall into the mid 20s, however with cloud
cover expected much of the night...model guidance may be a bit too
cold.
Friday through Wednesday...
Surface high pressure will be in control on Friday with the ridge
axis over the Devils Lake basin...with light winds and high temps on
Friday in the upper 20s.
By Saturday...high pressure retreats toward the Ohio valley and will
see return flow across the region ahead of the next system. A trof
of low pressure will cross the area on Sunday...but limited moisture
will result in some light snow with little accumulation expected.
Otherwise...a more organized system looks to develop by late Monday.
Southerly winds should become a bit breezy with a tightening
pressure gradient...and temperatures will be slightly warmer. Some
precipitation should occur right at the end of the forecast
period...with mainly light snow in the north and possibly a mix in
the south.
&&
.AVIATION...(For the 12Z TAFS through 12Z Wednesday morning)
Issued at 635 AM CST Tue Nov 29 2016
Complex aviation forecast this morning as FAR has gone to VFR with
all other sites remaining IFR. Vicinity of surface low now over
tri-state border area (Wheaton SD) will see widely varying cigs
until low pulls further east, at which time FAR should go IFR for
remainder of day. This should occur by noon. Will see rain
gradually change to snow by noontime at DVL and overnight for all
other locations. Breezy NW winds across eastern ND.
&&
.FGF WATCHES/WARNINGS/ADVISORIES...
ND...None.
MN...None.
&&
$$
UPDATE...JK
SHORT TERM...Speicher
LONG TERM...Hopkins/Speicher
AVIATION...Speicher
Area Forecast Discussion
National Weather Service Grand Junction CO
848 AM MST Tue Nov 29 2016
.UPDATE...
Issued at 848 AM MST Tue Nov 29 2016
Updated to cancel the winter weather advisories for portions of
northwest colorado and the upper colorado river valley where
snow has ended. latest models indicated that isolated showers
remain possible through the early part of the afternoon, however
additional accumulations will be light and localized. snow will
continue in the mountains of northwest and central colorado so
highlights continue in those areas.
&&
.SHORT TERM...(Today through Wednesday)
Issued at 244 AM MST Tue Nov 29 2016
Webcams across the area show snow continuing across portions of
the forecast area this morning. These webcams across the Grand
and southern valleys including Grand Junction, Cortez, Durango,
and Pagosa Springs all show some snow accumulation on the order
of a few inches. As far as radar is concerned at this hour, some
returns can be seen but they look to be very diffuse and waning at
that. In other words, they don`t look very impressive. Infrared
satellite matches up very nicely with the snow that occurred
earlier and showed some enhancement over these areas. Now, cloud
tops look to be warming which is an indication of less lift and
thus, less precipitation. This all matches up with our very short
range models including the RAP and HRRR which show precipitation
dwindling down to very little near daybreak. The NAM12 and GFS are
a little more aggressive and keep fairly widespread, albeit light,
snowfall in the picture through most of today. With all this in
mind, will keep the warnings and advisories in place with this
mornings package.
For the remainder of the day then, on again off again showery
type precipitation for the higher terrain with some continuing
accumulations possible though not as great as seen over the last
few days. Some of the snowshowers may hit the valleys too but do
not anticipate much accumulation. Clouds will finally start to
lift as we head towards mid-afternoon and the early evening hours
except the mountains where they`ll persist.
By this evening, snow will finally end for just about the entire
CWA. The northern mountains may see some lingering snow showers
thanks to northwesterly flow and orographics but no significant
accumulations expected. Skies will clear tonight which will likely
lead to some fog for those valley locales more prone to fog
formation.
Wednesday looks to be a decent in-between day as a weak short-wave
ridge moves in. Northwest flow will continue with partly cloudy
skies expected as we wait for the next system to approach from the
northwest as early as Thursday morning. Temperatures will remain
below normal through the period.
.LONG TERM...(Wednesday through Monday)
Issued at 249 PM MST Mon Nov 28 2016
The next disturbance is expected to drop in from the northwest
Thursday through Friday, but models are not in agreement with the
details. The GFS drops the upper low circulation into Utah by
Thursday evening with southerly flow showing some enhancement in
snowfall over northeast Utah and northwest Colorado. This low then
dives south into Mexico by Friday and splits from the main trough,
leaving our CWA in the deformation zone which would limit any
significant snow at this time. The ECMWF on the other hand brings
this system across as an open wave and never splits the cutoff
low. Timing is similar in terms of precipitation with northeast
Utah and northwest Colorado being favored so kept slight chance to
chance pops in for this period due to low confidence in the
details. Dry air then works in from the northwest Friday afternoon
and evening with a ridge of high pressure building over the
eastern Pacific (just off the west coast) by the weekend. Dry
weather is expected through the weekend with the chance of precip
increasing towards Monday as another disturbance drops in from the
Pacific Northwest and moves across the northern Rockies, clipping
the northern mountains.
&&
.AVIATION...(For the 12Z TAFS through 12Z Wednesday morning)
Issued at 244 AM MST Tue Nov 29 2016
Low ceilings and visibilities persist across the forecast area
this morning and will likely continue through much of the day.
Some showery snowfall will also likely continue especially over
the mountain TAF sites so expect ILS breakpoints to be hit for the
most of the day. Conditions will improve after about 21Z as
ceilings start to lift and most precipitation comes to an end. The
next concern then becomes fog for the overnight hours. Too far out
to include for now but something to consider as we get closer to
the overnight hours.
&&
.GJT WATCHES/WARNINGS/ADVISORIES...
CO...Winter Storm Warning until noon MST today for COZ004-009-010-012-
013.
Winter Weather Advisory until noon MST today for COZ003-005.
UT...None.
&&
$$
UPDATE...NL
SHORT TERM...TGR
LONG TERM...MDA
AVIATION...TGR
Area Forecast Discussion...UPDATED
National Weather Service Huntsville AL
940 AM CST Tue Nov 29 2016
.NEAR TERM...(Rest of Today)
Issued at 847 AM CST Tue Nov 29 2016
Morning satellite imagery shows generally clear skies across the
region aside from some lingering stratus/fog in a few locations. This
stratus/fog has been diminishing rather rapidly over the 90 minutes.
The late evening/overnight shower activity and associated surface
trough/cold front has pushed well south and east of the region.
North of the "front", winds have already shifted back to the south in
response to lowering pressures across the central plains. This low
across the plains will continue to deepen and move east helping
deeper moisture surge northward toward our region later today. The
short range/mesoscale models overall are in fairly good agreement
with the evolution of this system. The primary questions surround
the timing/mode of convective developing with the advancing warm
front (and later the cold front) along with potential severity of
convection.
Current thinking is that we likely will see isolated/scattered
convective development across north Alabama toward sunset along the
leading edge of the advancing warm front. This solution is supported
by both the CAMS and the WRF/HRRR guidance. Although the low level
hodograph curvature is not overly impressive at this time, the
combination of bulk shear well above 60 knots and MLCAPE exceeding
750 j/kg would be sufficient to supporting rotating storms.
As the surface low deepens somewhat and lapse rates aloft steepen,
the curvature becomes much more impressive late evening/midnight time
frame. This would be just along/ahead of a the broken line precedingthe
cold front. The HRRR guidance shows individual rotating cells within
the line and that seems quite reasonable. The CAPE gets stretched
slightly as you approach the AL/GA border but not certain we would
see significant weakening (or rapid weakening) as the decrease in
thermodynamic buoyancy may be offset by kinematic forces.
In terms of tornadic potential, the combination of thermodynamics
and kinematics appear favorable for at least a brief tornado or two
withing storms that can become more isolated and maintain rotative
properties for some time. The question will become the boundary layer
interactions and relative/mesoscale backing and convergence. So,
having said all that, the current forecast looks to be in quite good
shape overall. Do not anticipate significant changes this morning
other than some minor tweaks to account for temperature trends. The
record highs for today at HSV/MSL are both 76. We may be pushing
those close.
.SHORT TERM...(Tonight through Thursday)
Issued at 328 AM CST Tue Nov 29 2016
Things may ramp up rapidly this evening, as the axis of an upper
level trough shifts eastward. The low level jet is expected to
intensify between 00Z and 03Z, while a surface trough develops along
the MS River. A frontal boundary will move from west to east through
the evening and overnight hours, with a line of showers and
thunderstorms developing along the front over MS. Surface cyclogensis
is expected along this boundary, in response to the strengthening
jet, and the latest track has the low moving just to our NW. The line
of storms is expected to reach NW AL by 03Z and move across the
forecast area, exiting around daybreak. There may be some lingering
showers and thunderstorms across our eastern counties through the
late morning, as the main cold front moves through and moisture
remains high. There is still some uncertainty surrounding the timing
of the main line of storms, and have used blended guidance for the
PoP forecast.
In terms of the severe threat with this round of activity,
everything essentially hinges on how far north the warm front lifts
prior to the cold front reaching the area. Based on a fairly good
consensus of short term guidance, it does appear likely that the
high dewpoints will reach into our TN Counties, leaving the entire
area with dewpoints in the lower 60s by late evening. Along with
these higher dewpoints, instability will be higher, with surface
based instability values reaching as high as 1000 j/kg. As is
typical for these overnight events, forecast soundings suggest the
boundary layer decoupling overnight, however this is not probable
given the extensive cloud cover and WAA. So, if we do realize these
higher dewpoints, there is no reason to think that these higher
instabilities will not be realized as well. So, what does this mean
for the TN Valley? Well, our wind shear will certainly be more than
sufficient for organized thunderstorms and the curved hodograph
suggests that at least our western counties will see a threat for
supercellular structures. With low level wind shear over 30 kts, the
threat for tornadoes is certainly there. Additionally, 0-8km shear
approaching 80kts will mean a higher probability for any supercells
that do develop to be long track. We will have to closely monitor
the northward progression of the warm front, along with the track of
the surface low, as any deviation from what is currently forecast
will change the potential severe threat over the area. It should
also be noted that the greatest threat will be west of Interstate
65, with the threat diminishing further east as the dynamics shift
off to the north and individual cells congeal into a line.
As stated above, the precip chances will end during the morning
hours, with lingering light showers possible across the east. The
axis of the broad upper trough will flatten, with zonal flow
expected late Wednesday night. Under mostly clear skies,
temperatures will cool quite a bit, with overnight lows in the upper
30s. Dry conditions will persist during the day Thursday, with
seasonal temperatures expected.
.LONG TERM...(Thursday night through Monday)
Issued at 328 AM CST Tue Nov 29 2016
The extent that the trough and shortwaves being ejected E/NE out of
the western trough remains to be seen. The latest ECMWF has trended
more towards the solutions from the GFS, GEM, and Ensemble means and
shows a slower progression. Believe that models are a bit too quick
in bringing precip back into the area with most guidance showing
some light precip starting Saturday afternoon. Reason being is the
amount of dry air over the area from the high pressure system that
settles in Thu/Fri. GFS forecast soundings and model progs indicate
winds aloft remain out of the W during the day Sat and at the
surface only begin to transition to the S by the evening. This
should effectively hold off any precip Saturday and have nudged PoPs
down.
The other concern is that models are disagreeing with the track of
surface features that develop downstream of the western trough. The
GFS and GEM move a low pressure system on Sunday from TX to SC with
the center of the system remaining to our south. The ECMWF is a bit
further north with the system on Sunday. This variation in guidance
leaves greater uncertainty in the forecast this weekend. Ensemble
probabilities for precip suggest a solution somewhere in the middle
of the operational guidance but will wait one more model run for
better consistency before increasing PoPs.
There is potential for another round of strong to severe storms
during the Monday to Tuesday timeframe as the western trough finally
shifts east and moves across the area. But due to consistency issues
in the guidance will put only a slight chance of thunder in the
forecast.
Used a blend of guidance for temps from Friday through Monday.
Expect near normal temps through the extended period. Depending on
which model verifies temps could wind up being a bit warmer but will
wait for better agreement before making changes.
&&
.AVIATION...(For the 12Z TAFS through 12Z Wednesday morning)
Issued at 530 AM CST Tue Nov 29 2016
VFR conditions will prevail at the KMSL and KHSV terminals through
00Z, with mostly clear skies and southerly winds in the 10 to 15 kt
range. Forecast confidence drops tremendously after 00Z, as a potent
disturbance moves into the region. Went with a more pessimistic
forecast, despite low confidence, with thunderstorms prevailing at
KMSL from 02Z to 05Z and at KHSV from 03Z to 07Z. This timing may be
off a tad, but with the latest guidance, feel that this is the most
probable time for convection. Future TAF issuances may alter the
timing slightly as confidence grows. Lowered visibilities and gusty
winds will accompany the thunderstorms. Convection should end from
west to east beginning at 05Z, with MVFR cigs remaining through the
end of the forecast period.
&&
.HUN WATCHES/WARNINGS/ADVISORIES...
AL...NONE.
TN...NONE.
&&
$$
NEAR TERM...15
SHORT TERM...73
LONG TERM...Stumpf
AVIATION...73
For more information please visit our website
at weather.gov/huntsville.
Area Forecast Discussion
National Weather Service Northern Indiana
641 AM EST Tue Nov 29 2016
.SYNOPSIS...
Issued at 353 AM EST Tue Nov 29 2016
Primarily dry conditions expected during the day today with highs in
the mid to upper 50s. There is a low chance of light rain tonight
through tomorrow. Cooler air will then filter into the region late
Wed through Friday. This could lead to some lake effect rain and
snow showers north of highway 6 but little to no snow accumulation
is expected at this time.
&&
.SHORT TERM...(Today and Tonight)
Issued at 353 AM EST Tue Nov 29 2016
Well-established dry slot/isentropic descent bringing a quick end to
rain this morning. Dry conditions will persist through most of the
day but cloud forecast remains a difficult one. In addition to some
passing mid/high clouds, forecast soundings/RH fields suggest there
could be some lingering low clouds in the morning followed by a
quick return of low level moisture this evening as SW flow/theta-e
advection ramps back up ahead of strong upper jet and shear vort
max. This potentially leaves a somewhat limited window for sun and
mixing. However, based on upstream obs and limited saturation in
morning RAP and HRRR soundings, low clouds should fully erode this
morning with just some passing high clouds. This should give enough
time for adequate mixing to capitalize on warm thermal profiles
aloft before low clouds return. Stayed close to inherited forecast
of mid to upper 50s but could easily bust if low clouds linger or
redevelop sooner. Did expand low chance PoPs for our N/NW counties
this evening though. Several models suggest aforementioned theta-e
surge could be enough to touch off a few iso showers given steep
midlevel lapse rates (500mb temps near -28C in our NW). Could even
be an isolated clap of thunder given modest elevated instability.
Not much support in CAM`s and will be very light/isolated if it does
occur but nevertheless worthy of a low chance mention. Overnight
lows will remain in the 40s with abundant clouds and continued
southerly flow.
&&
.LONG TERM...(Wednesday through Monday)
Issued at 353 AM EST Tue Nov 29 2016
Precip chances linger in our eastern counties on Wed as weak wave
ripples along baroclinic zone to our SE. Deterministic models still
struggling with how far NW adequate moisture will get. Trimmed back
inherited PoPs slightly based on latest trends but still could see a
few light/sct showers along and east of I-69 where low chance PoPs
were retained. CAA doesn`t really ramp up until late Wed so highs
around 50F expected for most locations.
Cool W/NW flow then envelopes the region Wed night through Friday.
Several good chances for lake effect/enhanced precip. The first
arrives Wed night into Thu as a pair of decent shortwaves swing
through the Southern Great Lakes. 0-2km delta theta-e values
approach -1 C/km with abundant/deep synoptic moisture and Lake MI
temps running well above normal (around 10C). Inversion
heights/convective depths also running around 10kft. This should
support a good lake response despite relatively mild airmass (850mb
temps only around -4C). Lack of real cold air (and relatively mild
conditions to date) also lead to a messy precip type forecast. Temps
will likely hover in the 30s with limited diurnal range due to
widespread overcast conditions. Forecast soundings would suggest
that any heavier precip rates would likely fall as snow given very
shallow warm layer. However, ground is still fairly warm (as will be
the roads) and lighter precip will likely fall as rain, especially
during the day Thu. Therefore, chances for any meaningful or
impactful snow accumulation appear low. Biggest impact may just be
reduced visibility in heavier snow showers, similar to first cold
air/lake effect outbreak earlier this month. Another round possible
on Friday, although moisture/instability not quite as favorable
during that time and just low chance PoPs warranted.
First half of the weekend still appears dry. Next large-scale system
approaches early next week but GFS and ECMWF still offering very
different solutions on timing/evolution. Stayed close to consensus
PoPs with plenty of time for adjustments.
&&
.AVIATION...(For the 12Z TAFS through 12Z Wednesday Morning)
Issued at 630 AM EST Tue Nov 29 2016
Conditions have dried out across the area as strong lead vort max
has exited to the east. Some patchy MVFR cigs are still affecting
KFWA as of 11Z. Near term higher res guidance does indicate
continued slow northward expansion of IFR/MVFR upstream stratus
across southern Illinois into central Indiana this afternoon. KFWA
likely will be on northern fringe of possible impacts, with some
potential that 1-2k ft cigs could try and reach terminal during
late morning to early afternoon hours before better mixing ensues.
Confidence in this scenario is quite low with expectation that
greater threat will remain south of KFWA so have maintained VFR
conditions after 15Z. Better low level moisture
transport/convergence to lift back across northwest/north central
Indiana this evening, when confidence in MVFR cigs is greater with
a potential of IFR conditions late in this period. In addition,
the combination of steep mid level lapse rates and approach of
another short wave could be enough to generate isolated/scattered
showers this evening. However, low confidence in sufficient
moisture depth to realize elevated instability precludes a mention
with the 12Z TAFS. Southwest winds of the 10-15G20KT nature are
expected today, but gusts should diminish sharply by early
evening.
&&
.IWX WATCHES/WARNINGS/ADVISORIES...
IN...NONE.
MI...NONE.
OH...NONE.
LM...Small Craft Advisory until 1 PM EST this afternoon for LMZ043-
046.
&&
$$
SYNOPSIS...AGD
SHORT TERM...AGD
LONG TERM...AGD
AVIATION...Marsili
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Area Forecast Discussion...UPDATED
National Weather Service Jackson MS
945 AM CST Tue Nov 29 2016
...SEVERE THUNDERSTORMS EXPECTED AGAIN THIS AFTERNOON THROUGH
TONIGHT...
.UPDATE...
Updated for morning discussion.
&&
.DISCUSSION...
The current forecast appears to be on track for this morning. Latest
surface analysis shows the stationary front over our southern
counties late this morning. LIX sounding this morning showed cape of
around 1200 j/kg with some lower 70s dewpoints south of the
boundary. Latest 12z Nam shows effective storm relative helicity 300-
400. With the locally heavy rain potential WPC has put out a
marginal risk for flooding for the cwa. Looking for this afternoon
the current expectations for severe weather modes has not changed as
the warm frontal boundary pushes northward...then as the cold front
pushes through overnight. Latest HRRR shows some isolated strong
storms pushing north across the region with warm front. Otherwise
made slight adjustment to hourly temps,and afternoon highs. Kept
current pops the same./17/
Prior discussion below:
Today and Tonight...
The main forecast concern across the ArkLaMiss region for today and
tonight is the threat for another two rounds of severe thunderstorms
- one this afternoon and another later this evening and tonight.
Synoptically, a deep low pressure system continues to spin over the
Upper Midwest this morning with the shortwave that brought
yesterday`s round of storms lifting north and east of our area.
Another shortwave will round the base of the upper low today, while
forecast surface pressure falls suggest that a surface low will spin
up near the ArkLaMiss Delta.
This low will help to focus a lifting warm front across the central
portions of our forecast area this afternoon - the first potential
round of severe weather. Afternoon thunderstorms will have an
increasingly unstable airmass to tap into. MLCAPE values of 1500-
2000 J/kg are possible behind the warm front this afternoon. Any
thunderstorms that develop will also advance into increasing deep
layer shear (0-6 km shear of 50-70 kts), indicating a favorable
environment for supercells. Directional shear will not be as great
as yesterday, though still some veering from SSW to SW with height.
All modes of severe weather will be possible, as steep mid-level
lapse rates and the potential for longer lived supercells increase
the chances for hail and damaging winds. 2000 ft LCL heights and
adequate amounts of low-level shear and helicity will support the
possibility of tornadoes with supercells.
The second possible round of severe weather is not expected to
develop across our area until mainly after 6 PM tonight and should
last through the early morning hours of Wednesday. The surface low
will bring a cold front into the Delta region by around 6 PM, with
the possibility of a few thunderstorms ongoing along it by that
time. With deep layer shear being more parallel to this cold front
storm mode will likely be more linear, though again 60-70 kts of 0-6
km shear would suggest that embedded supercells are possible. Steep
mid-level lapse rates and the presence of dry air through the mid
levels will continue to support the possibility of a large hail and
damaging wind threat. Increasing low-level wind shear and helicity
with a strengthening low-level jet overnight will prompt a
significant threat for tornadoes in our graphical and text Hazardous
Weather Outlook products. With the possibility of nighttime
tornadoes, residents are urged to have an emergency plan in place
should Watches or Warnings be issued for their location. QPF totals
of 1 to 2 inches across eastern portions of the forecast area
indicate a marginal threat for flooding, but recent long-term dry
conditions in those areas should limit the overall threat for flash
flooding tonight. Heavy rainfall could still produce localized
flooding in low areas. /NF/
Wednesday through early next week....
Another round of wet weather looks to take shape at some point
between this weekend and middle of next week. There are timing
issues with this next system, but models depict that another low
will develop in the Gulf/Texas coast and track northeast into our
CWA ahead of a trough developing across the Intermountain West. This
low will allow moisture to increase into our region as well as some
precip. The ECMWF is the fastest with bringing this through over the
weekend, while the GFS and Canadian are much slower and wait until
early next week. /28/
&&
.AVIATION...
For the 12Z TAFs...Low clouds and patchy fog across portions of the
area this morning will primarily impact KGTR, KMEI, and KHBG through
about 14Z-15Z before lifting. Then increasing moisture from the
south will lead to a potential for scattered showers and
thunderstorms this afternoon. Confidence in timing and location of
any storms is too low to include in TAFs at this time, so amendments
may be necessary if afternoon thunderstorms develop. There is
greater confidence in a second round of storms generally after 00Z
Wednesday, so have timing of greatest confidence for impacts from
these storms in TAFs. Expect gusty and erratic winds, locally heavy
rainfall, and MVFR or lower conditions as showers and storms move
through each site. /NF/
&&
.PRELIMINARY POINT TEMPS/POPS...
Jackson 78 54 64 36 / 54 92 31 2
Meridian 78 58 67 36 / 50 100 75 3
Vicksburg 77 49 62 34 / 54 81 13 1
Hattiesburg 79 61 68 37 / 48 100 79 3
Natchez 77 52 62 36 / 51 83 13 1
Greenville 73 48 59 35 / 51 73 13 1
Greenwood 76 49 61 34 / 48 83 13 1
&&
.JAN WATCHES/WARNINGS/ADVISORIES...
MS...None.
LA...None.
AR...None.
&&
$$
17/06/28/06
Area Forecast Discussion
National Weather Service Blacksburg VA
1006 AM EST Tue Nov 29 2016
.SYNOPSIS...
A weak front will remain just west of the area this afternoon into
early Wednesday allowing a series of upper disturbances to track
along the boundary. This will result in periodic rounds of
rainfall this afternoon and again later tonight into Wednesday. A
stronger cold front will pass through the region Wednesday night
bringing drier and cooler weather for the end of the week.
&&
.NEAR TERM /THROUGH TONIGHT/...
As of 950 AM EST Tuesday...
Axis of heavier showers now crossing the Blue Ridge along the
residual outflow from overnight and along a warm front lifting to
the northeast. Decent rainfall amounts along the swath of precip
with a good third to one half inch currently. Latest HRRR shifts
this band, in advance of the stalled front along the western
slopes, quickly east into the afternoon with most significant
rainfall exiting the southeast by mid afternoon if not sooner.
Cant totally rule out a rumble of thunder over the far south and
east as guidance shows some weak instability under a swath of good
upper diffluence within the very mild air that has advected north
from overnight. However appears most convection likely to be even
farther to the southeast where deeper instability will reside so
leaving out mention.
Otherwise bumped up pops to higher likely/categorical along the
axis of rainfall as it progresses east into the piedmont through
early afternoon. This should bring about a lull in all but the far
southern sections where plan to leave in some low pops for late in
the day once the main band slides east. Southwest winds remain
quite strong aloft but currently too high to mix very strong
speeds to the surface despite lack of much of an inversion where
temps have warmed. Highs again appear mild, mostly 60s to even
around 70 southeast, but tricky farther north where still stuck in
the cool pool north of the warm front. Thus lowered highs back
closer to 60 far north/west where may see a brief surge once the
rain tapers per latest Met mos.
Previous discussion as of 400 AM EST Tuesday...
First round of much needed rainfall moving through the region
early this morning. This rainfall is associated with a
dampening/shearing out short wave emanating from a deep upper low
centered across the Midwest. Rainfall amounts so far have all been
less than an inch ranging from around 2/3rd or a letter better
across northwest NC into Grayson county VA to only a few hundreths
across the Piedmont. Far from a drought buster, but certainly
welcome, especially with the best rainfall in the most severe
drought Blue Ridge mountain forest areas. The last piece of energy
from this short wave will traverse the region through the morning
hours with additional light rainfall amounts, mostly from this
point forward across the northern and eastern portions of the
forecast area. Additional rainfall during the afternoon/evening
will be limited, but cannot completely drop pops below mentionable
values as broad southwest flow aloft prevails and additional
upstream disturbances are on the way. As the upper low continues
to move slowly east through Wednesday, a more significant and
final disturbance is progged to round the base of the trough and
bring another round of rainfall beginning late tonight in the west
spreading further east Wednesday. With a better tap into the Gulf,
this one promises to bring more beneficial rainfall to the area,
but will leave further discussion on that to the next section.
The GFS is fairly aggressive on instability late tonight/early
Wednesday as the upper-level feature approaches and elevated
thunder cannot be ruled out, but given that this is the only model
indicating such and the potential for a cool, stable boundary
layer, will not include thunder through this period at this time.
The strong surface winds associated with the 50kt+ LLJ will shift
east of the CWA during the morning hours. A few gusts toward 40kts
still not out of the question through the morning hours along the
higher peaks of the Blue Ridge across Bedford/Amherst, but not
enough coverage to warrant a new Wind Advisory. A less impressive
LLJ will approach the region from the west late tonight in
association with the next short wave, but speeds look to be well
below advisory criteria east of the divide and thus will not issue
any further wind headlines at this point.
850mb temps surge well into the double-digit range today of +12C
to +13C well north into the northeast U.S. A non-diurnal
temperature trend was already under way this morning with balmy
late November temperatures in the 50s and which have been rising
overnight. By afternoon this will equate to temperatures well into
the 60s except 50s higher mountain elevations, some 20 degrees
above normal. Look for a very mild night tonight/Wednesday
morning as strong southerly winds continue to transport warm/Gulf
air this direction. Low temperatures Wednesday morning will be
some 30 degrees above normal in the mid 50s to near 60!
&&
.SHORT TERM /WEDNESDAY THROUGH FRIDAY NIGHT/...
As of 200 AM EST Tuesday...
On Wednesday, a shortwave trough will head northeast across the
region on the east side of an upper low/trough centered across the
north central part of the nation. At sunrise, rain is expected across
primarily the western and southwestern portion of the area. As the
day progresses, coverage will translate eastward in concert with a
shift eastward of the upper trough. By Wednesday evening, the
shortwave trough will be exiting the eastern portion of the area
with some trailing precipitation across the eastern quarter of the
area.
The upper systems associated 850mb trough axis will cross the area
Wednesday evening, and northwest flow will commence. Although, the
latest guidance suggests not the best cross barrier flow with an
orientation more west-northwest. Look for scattered rain showers
across the western slopes of southeast West Virginia through the
overnight hours. Enough cold air may arrive by sunrise Thursday for
a mix with or change over to snow showers.
Thursday through Friday night, the upper low/trough near the Great
Lakes region will make gradual progress eastward towards and over
the Canadian Maritimes. This will keep the region under a prevailing
west to northwest flow, all while an west-east oriented surface
ridge axis noses into the western parts of the area. We expected
flurries/sprinkles to conclude the precipitation Thursday morning
across the western parts of Greenbrier County, WV. The vast majority
of the area will be dry Thursday into Friday night. A disturbance
within the northwest flow is expected to pass through NY/PA on
Friday. While most of the energy and moisture with this system will
stay north of the area, enough may make it south enough to yield
scattered upslope flurries/sprinkles across western Greenbrier
County Friday into Friday night.
Temperatures will trend colder during this portion of the forecast.
Readings on Wednesday will be 15 to 20 degrees above normal. By
Friday, temperatures closer to normal for this time of year are
forecast.
&&
.LONG TERM /SATURDAY THROUGH MONDAY/...
As of 330 PM EST Monday...
Saturday brings possibly a transition day toward wetter
conditions late weekend, but there are unresolved differences
among the models in this regard. Highs near climo for early
December. Still considerable divergence persisting in the model
solutions for the latter part of the extended. 00Z/28 Euro came in
quite wet for weekend with a deep trough located over Texas and
the Gulf opening up with strong moisture return along with
favorable dynamics. Latest 12z/28 operational EC run maintains
similar solution with this fairly bullish scenario for additional
precipitation. This in distinct contrast to last few GFS/CMC runs
which keep western trough much further west, back across AZ or
northern Mexico with a flat zonal flow across the east and little
to no northward moisture return through Sunday. Latest PMDEPD
discussion is favoring the run- to- run consistency of the GFS and
maintaining high pressure over our area through Sunday and
suppressing significant precipitation well to the southwest. Have
raised PoPs into chance range starting early Sunday but confidence
is not particularly high.
&&
.AVIATION /15Z TUESDAY THROUGH SATURDAY/...
As of 645 AM EST Tuesday...
Poor aviation conditions expected through the TAF valid period. A
broad upper low pressure area centered across the western Great
Lakes will drift slowly east through Thursday. An initial short
wave and associated cold front were moving through the region this
morning with a couple of waves of light rainfall. The later area
of light rain will traverse the forecast area during the morning
hours, exiting to the east during the early to mid afternoon.
Little additional measurable precipitation is expected during the
afternoon. The next wave of precipitation, associated with the
main disturbance rounding the base of the deep upper trough and
originating from the southeast states, will approach the area late
tonight and early Wednesday. There are some indications that there
may be a period of MVFR or better cigs west of the Blue Ridge for
a brief period this afternoon toward 00Z before conditions sock
back in for good for the rest of the night. However, this
improvement is not expected east of the Blue Ridge where south-
southeast winds will hold the low-level moisture in place.
Otherwise, mostly MVFR-IFR cigs through midday, becoming mostly
IFR-LIFR after 00Z in DZ and FG. The next round of rain will
arrive around 09Z in the west, closer to 12Z in the east.
Visibilities will generally be MVFR to low end VFR through mid
day, VFR during the afternoon, becoming mostly MVFR to locally IFR
overnight in DZ, FG, and -RA.
The strong low-level jet that traversed the area overnight has
generally pushed northeast of the area and is weakening. Winds
have dropped below advisory criteria. Will carry LLWS at KLWB for
a couple more hours, but not include anywhere else. Winds across
the Piedmont have largely decoupled showing east 3-5kts.
Otherwise, mainly seeing SSE-SSW winds 5-7kts with low end gusts
yet in a few places. Winds through much of the TAF valid period
will be SSE-SSW 4-8kts with low end gusts by afternoon many
locations, decreasing after 00Z and trending more SSE.
Medium confidence in ceilings and visibilities through the TAF
valid period.
Medium confidence in wind speed through the TAF valid period.
Medium to high confidence in wind direction through the TAF valid
period.
Extended aviation discussion...
Improving conditions expected after the upper low and final short
wave move east of the area Wednesday night. Conditions should
become largely VFR east of the Blue Ridge into the weekend.
Upslope clouds and potentially a weak clipper system could bring a
low chance of rain or snow showers into the Alleghanys Thursday
and Friday along with lingering MVFR cigs before conditions
improve there as well.
&&
.FIRE WEATHER...
As of 430 AM EST Tuesday...
Beneficial rainfall of 1/2 to isolated near 1 inch amounts
observed across the southwest part of the forecast area, which has
been the driest area with the most significant drought and forest
fire conditions in recent weeks. Thus, this rainfall is very good
news. Now with winds also in a diminishing trend, fire threat has
been greatly reduced. Additional rainfall expected
tonight/Wednesday should further alleviate any fire weather
concerns in the short term.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...None.
NC...None.
WV...None.
&&
$$
SYNOPSIS...JH/RAB
NEAR TERM...JH/RAB
SHORT TERM...DS
LONG TERM...DS/PC/RAB
AVIATION...AMS/MBS/RAB
FIRE WEATHER...
Area Forecast Discussion
National Weather Service Columbia SC
250 PM EST Tue Nov 29 2016
.SYNOPSIS...
A diffuse front will remain in the forecast area through tonight.
A cold front approaching Wednesday will move through the forecast
area Wednesday evening. Breezy conditions will be associated with
these fronts. Much above normal temperatures will lower behind the
cold front over the weekend.
&&
.NEAR TERM /THROUGH TONIGHT/...
A lake wind advisory remains in effect through 5 pm today. Expect
sustained wind speeds from 10 to 15 kts with gusts around 20 kts
through the afternoon. The 850 mb jet will weaken late this
afternoon with subsiding gusts. Winds will stay up overnight from
5 to 10 kts.
A weak boundary will remain over the region during the period. 850
mb moisture advection, synoptic-scale lift and a weak upper
disturbance will support showers through the afternoon. The
heaviest rainfall will be in the Piedmont and northern CSRA due
to the proximity to the convergence boundary and upslope flow.
However hi-res models support the main area of showers moving
eastward and breaking up. Thunderstorms are unlikely this
afternoon but cannot rule out isolated coverage with LI values
from 0 to -1.
Shower coverage will diminish late this afternoon and evening as
synoptic-scale lift decreases and the weak upper disturbance moves
out. Models show the weak boundary lifting north overnight keeping
the slight chance of showers limited to the northern Midlands.
Warm advection and mixing will allow for well above normal
temperatures. Highs today will be in the mid to upper 70s.
Model guidance suggested slightly warmer highs, near record, but
confidence is lower with overcast skies. Diurnal range will be
limited. Overnight lows in the mid 60s. Abundant moisture and
decent mixing may allow for widespread stratus late tonight
through early Wednesday morning.
&&
.SHORT TERM /WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT/...
The models are in close agreement depicting the approaching cold
front moving through the forecast area Wednesday evening. Much of
the upper-lift associated with a dampening shortwave trough
should hold off until Wednesday evening. Isentropic lift supports
a chance of showers early Wednesday with the chance increasing
through the day into the early evening hours. Shear will remain
strong. The NAM and GFS indicate h85 wind from 50 to 55 knots.
The severe thunderstorm threat should be limited by weak
instability. SPC has area in a marginal risk for severe
thunderstorms. The NAM displays surface-based LI values around
-1. However, instability could become a little greater because of
the favorable diurnal timing just ahead of the cold front with
near record temperatures climbing to around 80 in some locations.
Any thunderstorms could possibly contain damaging wind because of
the strong shear. The NAM and GFS were close with rainfall
amounts. The ECMWF had amounts a little greater. Followed a
guidance consensus which was close to the SREF mean. Expect
amounts mainly 0.2 to 0.5 of an inch.
It also will be generally windy ahead and along the front. The
NAM bufkit momentum transfer tool supports gusts 25 to 30 knots.
Another Lake Wind Advisory will be needed once again tomorrow.
Will not issue on this shift due to current Lake Wind Advisory in
effect until 5 pm.
Followed the guidance consensus for the maximum temperature
forecast. Mixing associated with the front favors the higher
minimum temperature guidance.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
Cool and dry weather is expected behind the front Thursday
through Saturday. The GFS and ECMWF indicate surface ridging
moving into the area with near zonal flow. The upper flow begins
to back ahead of the next system by Sunday through Tuesday. The
models indicate considerable moisture and isentropic lift. The GFS
and ECMWF MOS have pops 40 to 60 percent Sunday and Monday. The
models indicate near normal temperatures through the medium- range
period.
&&
.AVIATION /20Z TUESDAY THROUGH SUNDAY/...
A strong 850 mb jet and mixing today will create gusty conditions
through the afternoon. Expect sustained surface winds from 10 to
15 kts with gusts up to 25 kts. Gusts will diminish late this
afternoon as the 850 mb jet weakens.
A weak boundary in the Piedmont will be the focus for showers this
afternoon. Showers are currently just west of TAF sites but may
move eastward later this afternoon. A couple of fringe showers
will give sites brief periods of light rain over the next few
hours. The HRRR shows the main area of showers moving eastward
this afternoon, possibly bringing heavier showers to all sites.
However decreasing coverage limits confidence. Thunderstorms are
unlikely, but isolated occurrences are not out of the question.
Showers will subside across the area this evening. SSW surface
winds will stay up overnight around 5 kts with a 30 to 40 kt LLJ.
Decent mixing and abundant low level moisture will likely cause
IFR, possibly lower, ceilings tonight into Wednesday morning.
Models are in good agreement and Bufkit profiles for all sites
show deep low-level moisture. Fog and reduced visibilities may
coincide with the low stratus but moderate low-level wind speeds
suggest stratus will be the main threat.
EXTENDED AVIATION OUTLOOK...Expect breezy conditions to continue
through Thursday. A cold front will move through the region
Wednesday night and Thursday morning. Showers and possibly
thunderstorms may bring associated restrictions.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
GA...Lake Wind Advisory until 5 PM EST this afternoon for GAZ040-
063>065-077.
SC...Lake Wind Advisory until 5 PM EST this afternoon for SCZ015-
016-018-020>022-025>031-035>038-041.
&&
$$
SYNOPSIS...99
NEAR TERM...99
SHORT TERM...99
LONG TERM...99
AVIATION...99
Area Forecast Discussion
National Weather Service Caribou ME
344 PM EST Tue Nov 29 2016
.SYNOPSIS...
Low pressure will track across the region Tonight into Wednesday.
Another area of low pressure will move through Wednesday night
into Thursday.
&&
.NEAR TERM /THROUGH TONIGHT/...
Winter Weather Advisories remain in place with the ice potential
moved a bit further n and snowfall amounts pulled back across the
western and central areas.
Sfc analysis showed cold air damming across the interior downeast
region beginning to weaken as the high retreats to the e. Low pres
apchg from the sw will move off the Maine coast and run across the
Gulf of Maine tonight. Precip was in the form of snow across the
far north and a mix of snow/freezing rain in the Central
Highlands per the webcams and obs. Frozen precip has now gone to
rain across the downeast and coast as dewpoints rise into the 30s.
Enhanced banding seen on the MRMS and radar coverage across the
northern areas indicative of heavier snow or even sleet as seen in
southern Piscataquis County. First round of precip to move through
this evening w/a good round of snow for northern areas mainly n of
HUL TO MLT line. Some portions of the Central Highlands could pick
up close to 0.20 inches of ice before ending later tonight. A second
round of precip to move across the downeast region w/the low w/up to
0.75 inches of rain by midnight. This is due to a good 50 kt jet
moving in from the ssw. As the low pulls away, the RAP and HRRR
indicate some wrap-around moisture in the form of snow occurring
back across northern Maine overnight before ending Wednesday
morning, which will add to the snow totals. Temps will warm for a
time overnight into the low and mid 30s.
Caution needs to heeded here as snowfall rates up to 1"/hr this
evening will lead to some quick snowfall amounts. Timing will be
key here. Decided to blend in WPC`s guidance this round yielding
5-8 inches across northern Maine w/in a 12+ timeframe. If
snowfall rates continue longer at the aforementioned rate, then
amounts will need to be raised which could tip things into the
warning criteria. Decided on 2-4 inches for the Central Highlands
w/an inch or less s of the Lincoln-Topsfield region.
&&
.SHORT TERM /WEDNESDAY THROUGH FRIDAY/...
One area of low pressure will be moving away to the east on
Wednesday as another low begins to take shape near southern New
England. Between the two, we will remain cloudy with some spotty
showers, or flurries across the north. Precipitation from the new
low will begin to spread across the area from southwest to northeast
Wednesday evening, as rain Downeast and then snow across the north.
Snow over the north and rain Downeast will continue into early
Thursday morning. Boundary layer thicknesses are indicating a bit of
sleet and freezing rain may mix in over some central areas,
especially across the central highlands. As the low center tracks
along the coast precipitation should taper off to rain showers
Downeast around mid to late morning Thursday then taper off as snow
showers over the north by early Thursday afternoon. Thursday night
into Friday will then remain cloudy with some scattered rain and
snow showers over the north and a partly to mostly cloudy sky
Downeast as the upper trough slowly moves across the north and
dissipates.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
A trof both at the surface and aloft will linger across the
area Friday night through Saturday with the chance of a few snow
showers, mainly across northern and central areas. The trof will
begin to move off to the east Saturday night and Sunday with
partly cloudy skies and dry conditions expected. High pressure
will begin to move east on Monday. Another system may bring a few
snow showers by Tuesday. Temperatures through the period are
generally expected to remain below normal for this time of year.
&&
.AVIATION /19Z TUESDAY THROUGH SUNDAY/...
NEAR TERM: IFR across the northern terminals w/MVFR for KBGR and
KBHB this evening. All terminals to go IFR and perhaps LIFR
overnight w/snow and possible freezing precip for some of the
northern terminals especially HUL while KBGR and KBHB will see
rain.
SHORT TERM: Conditions will lower to IFR from south
to north Wednesday evening then remain IFR into early Thursday
morning. Conditions may improve to MVFR then VFR Downeast Thursday
afternoon but will likely remain MVFR across the north. MVFR
conditions over the north and VFR to MVFR conditions Downeast are
likely Thursday night through Friday.
&&
.MARINE...
NEAR TERM: SCA for the intra coastal waters looks good for the
overnight w/sustained winds of 20 kts or so and gusts to 25 kts.
Gales remain up for the outer waters as winds of 25-30 kts could
easily gust to 35 kts as a 45-50 kt jet from 925-850 mbs moves
over the waters this evening.
SHORT TERM: A gale for the offshore waters and SCA for
the intracoastal waters may be needed for east winds ahead of low
pressure Wednesday night. Winds may diminish for a period of time
Thursday, then increase to SCA in west winds Thursday night before
diminishing again on Friday.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...Winter Weather Advisory until 4 AM EST Wednesday for MEZ002-
005-006.
Winter Weather Advisory until 4 AM EST Wednesday for MEZ001-
003-004-010.
Winter Weather Advisory until 4 AM EST Wednesday for MEZ011-
031-032.
MARINE...Small Craft Advisory from 5 PM this afternoon to 7 AM EST
Wednesday for ANZ052.
Gale Warning from 7 PM this evening to 2 AM EST Wednesday for
ANZ050-051.
&&
$$
Near Term...Hewitt
Short Term...Bloomer
Long Term...Duda
Aviation...Hewitt/Bloomer
Marine...Hewitt/Bloomer
Area Forecast Discussion
National Weather Service Huntsville AL
137 PM CST Tue Nov 29 2016
.NEAR TERM...(Tonight)
Issued at 136 PM CST Tue Nov 29 2016
Latest surface analysis shows a low across the western Great Lakes
with a trailing cold front extending through central Missouri through
central Red River Valley. A stationary/warm front was situated
generally south of I-20 across AL/MS. The airmass along and south of
the warm front was quite juicy this afternoon with dewpoints well
into the 60s.
For tonight, the initial question is how quickly/how far north the
warm front progresses. Given the limited convective activity along
the gulf and southerly flow in place across the state, expect the
airmass to recover by late afternoon/early evening. The HRRR
continues to indicate isolated/scattered convective development
within the warm sector between 00z-03z and this seems reasonable
given little in the way of capping.
Hodographs become a bit more favorable for sustained rotating cells
within a (perhaps slow progressing) QLCS that will move across during
the late evening and overnight hours. Unlike normal cool season
events, if moisture does indeed recover as expected CAPE values
should easily reach the 500-750 j/kg range ahead of this line. Given
the combination of instability and sufficient shear, storms will
certainly have to be monitored for at least a brief tornado threat.
Based on the models trends toward more parallel (sw to ne) flow in
the mid levels, have beefed up QPF just a touch. This is also in line
with the latest projections from WPC. Temperatures will move very
little tonight with most areas not seeing a true FROPA until 12z or
thereafter.
.SHORT TERM...(Wednesday through Thursday)
Issued at 136 PM CST Tue Nov 29 2016
Convection, perhaps near-severe in sports or slowly diminishing,
will still be ongoing across our eastern counties at 12z on
Wednesday. The upper trough axis will push across by early afternoon
ushering in the "cooler" air. Will taper pops from west to east and
also temporally with all areas rain free by afternoon.
Weak surface high will build across the region Wednesday night into
Thursday with sunny and slightly below normal temperatures
anticipated.
.LONG TERM...(Thursday night through Monday)
Issued at 136 PM CST Tue Nov 29 2016
Fairly strong cold air advection will continue to advect drier air
into the area Thursday/Thursday night, via northwesterly flow. In
addition, light winds will continue over the Tennessee Valley, as
the surface high will not have moved much. This will allow for a
very good radiational cooling event by Friday morning. It should
allow lows to drop to near dewpoints to around 30 degrees.
Temperatures should rebound to near normal highs during the day on
Friday.
Models all develop a more zonal flow aloft originating from Texas,
as the high pressure remains over the area through Friday night. This
will be in response to a cut-off low that develops over the
southwestern U.S. This should keep highs and lows through Friday
night near normal/slightly above normal (normal highs mid to upper
50s/normal lows mid to upper 30s).
Models do advect deeper moisture eastward into the Tennessee Valley
ahead of it Saturday through Sunday. How far north the deeper
moisture gets and thus rainfall is the difference in the model
forecasts. At this point, including a blend for the forecast.
Saturday night through Sunday are keeping a 30 to 60 percent chance
of rain in the forecast. This likely will be the best time for more
widespread precipitation, but how much greatly depends on which model
solution is correct.
Early next week remains active, as the cut-off low kicks northeast
along the jetstream into Arkansas and into Kentucky. There could be
some stronger thunderstorm potential with this system, but too far
off to address at this point.
&&
.AVIATION...(For the 18Z TAFS through 18Z Wednesday afternoon)
Issued at 1124 AM CST Tue Nov 29 2016
A complex weather pattern is expected to unfold across the area over
the next 18-24 hours. Southerly winds will help to bring gulf
moisture into the region ahead of an approaching cold front. This
will increase cloud cover at both TAF sites, eventually lowering
ceilings to MVFR category after sunset. Expect scattered shra/tsra
during the evening hours with low probability of IFR conditions at
both KHSV/KMSL. Storms will become more numerous from west to east by
late evening and overnight with widespread MVFR and isolated/brief
IFR conditions. Cigs will slowly rise after mid morning on Wednesday.
&&
.HUN WATCHES/WARNINGS/ADVISORIES...
AL...NONE.
TN...NONE.
&&
$$
NEAR TERM...15
SHORT TERM...15
LONG TERM...KTW
AVIATION...15
For more information please visit our website
at weather.gov/huntsville.
Area Forecast Discussion
National Weather Service Wilmington OH
419 PM EST Tue Nov 29 2016
.SYNOPSIS...
An upper level disturbance will approach the area from the
southwest tonight allowing for showers to develop near central
Tennessee and Kentucky. The showers and isolated thunder will then
push northeastward into southern Ohio Wednesday morning. Most of
the rain will fall southeast of the I-71 corridor and then colder
air will enter in Wednesday evening behind a cold front.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
Currently the area is dry with an upper level low located over
Minnesota. Out ahead of the upper level low the first shortwave
will approach the area from the southwest around 3z Wednesday
morning. The shortwave is weak with the HRRR and NCEP WRF showing
some weak development out ahead of it. The main shortwave that
will be responsible for the rain will approach the area from the
southwest around 12z Wednesday morning. There still remains
uncertainty though on the track and strength of the shortwave
though. The NAM is stronger with the shortwave and tracks it
slightly further northwest than the GFS and ECMWF. The NAM also
develops a surface low and clips our southeastern zones. This
allows for Scioto county to briefly fall in the warm sector with
MU Cape values around 600 J/kg. SFC - 1 km bulk shear values also
approach 50 kts. The GFS is weaker with the surface low but still
shows some instability across the far southeast. Looking at
forecast soundings for Portsmouth, OH there is high shear but
instability is more elevated. For now have only added thunder
across the southeastern zones. Have also kept PoPs categorical
across the southeast as lift looks strong with the shortwave
(further supported by omega fields). On the flip side of things
our far northwestern counties will be on the edge of the precip
and will probably see very little in the way of precip through the
near term.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH FRIDAY/...
Wednesday after the sunrise the shortwave will be exiting the area
towards the northeast taking most of the rain with it. Wednesday
afternoon there might be some brief breaks in the clouds before
the upper level low in Minnesota begins to push east. As this
happens a band of PVA will push through the area. A surface cold
front will then push through with the PVA. The cold front will
enter our western zones starting around 18z and then clear our
eastern zones around 21z. Some high res models are hinting at some
showers with isolated thunder possible with the front. Looking at
forecast soundings there is some weak instability but confidence
remains low on if there will be any instability at all.
As the front pushes through the area Wednesday afternoon winds
will begin to pick up and with gusts of 25 to 30 kts possible.
Wednesday night into Thursday winds will stay gusty at times due
to CAA and a tight pressure gradient. Forecast soundings for
Thursday also keep 850mb saturated with clouds likely staying
around all day Thursday and into Friday. The NAM has the low layer
moisture staying around into Friday but has some partial clearing
across our southwest. 850 mb temperatures fall to around six degrees
below zero Thursday into Friday and with clouds around high
temperatures will likely struggle to get out of the lower 40s.
Have gone ahead and lowered high temperatures a bit Thursday into
Friday. It also should be noted that Friday morning the GFS is
saturating the low layers just enough to possibly have some
flurries. For now have left the mention out as the GFS appears to
be a bit to aggressive with the low layer moisture.
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
A quasi-zonal flow pattern will be in place at the start of the
weekend as our area will be in between a trough over eastern Canada
and a developing upper level trough/low over the southwestern United
States. Some weak pieces of energy will move quickly east across the
southern Great Lakes Friday night through Saturday night. While it
will be tough to rule out some spotty shower activity, the chance
appears low enough at this point to go with a dry forecast through
the first half of the weekend. Highs on Saturday will be at or a
little below normal, ranging from the upper 30s in the northwest to
the lower and mid 40s in the southeast.
There is quite a bit of model uncertainty as we head into next week
as both the 12Z GFS and the 12Z ECMWF have trended weaker and
farther south with the initial energy ejecting out of the trough
over the southwestern United States. The ECMWF is trying to phase
some of this energy with a short wave pushing east across the Great
Lakes Sunday into Sunday night while the GFS does not and keeps our
area mainly dry. Will therefore go ahead and trim back pops a bit
and just allow for some lower chances for primarily Sunday into
Sunday evening. Depending on the exact timing, if any pcpn starts
early enough on Sunday, it could be in the form of snow, before
transitioning over to rain as we warm up in the afternoon. Expect
highs on Sunday in the low to mid 40s.
There is also some disagreement with how fast the main energy will
eject northeast out of the western trough toward the end of the long
term period. The GFS is weaker and somewhat faster with this
compared to the ECMWF. Will go ahead and trend toward a blend and
allow for chance pops to spread in from the southwest Monday night
into Tuesday. Low level thermal fields are generally warm enough to
support all rain with this event. Highs will trend a little above
normal through the end of the period with highs by Tuesday ranging
from the mid 40s north to the lower 50s south.
&&
.AVIATION /20Z TUESDAY THROUGH SUNDAY/...
Some scattered to broken MVFR cu developed through late morning
but this has been eroding away in the developing low level WAA
pattern. Otherwise, expect mainly just some mid to high level
cloudiness through the rest of the afternoon and into this
evening.
A developing low pressure system will lift out of the lower
Mississippi Valley and into the upper Ohio Valley tonight into
Wednesday morning. This will allow for rain to develop after
midnight tonight and then overspread the TAF sites through the
early morning hours. As it does, cigs will lower into MVFR and
possibly IFR category through the pre dawn hours and then linger
through much of the morning hours on Wednesday. As the low pushes
off to the east, precipitation will taper off toward the end of
the TAF period but MVFR cigs will likely linger through the
period.
OUTLOOK...MVFR ceilings possible through Friday.
&&
.ILN WATCHES/WARNINGS/ADVISORIES...
OH...None.
KY...None.
IN...None.
&&
$$
SYNOPSIS...Haines
NEAR TERM...Haines
SHORT TERM...Haines
LONG TERM...JGL
AVIATION...JGL
Area Forecast Discussion
National Weather Service Marquette MI
405 PM EST Tue Nov 29 2016
.SHORT TERM...(This evening through Wednesday)
Issued at 404 PM EST TUE NOV 29 2016
WV imagery and RAP analysis indicated a closed mid/upper level low
over cntrl MN. At the surface, an elongated trough or occluded front
extended from cntrl MN through nrn Lake Superior. An area of mixed
rain and snow over cntrl Upper Michigan supported by 850-700mb fgen
was gradually diminishing as the stronger forcing lifts to the
northeast.
Tonight, Models suggest that 850-500 drying will spread across the
area. With levels also drying out, expect the remaining light pcpn
to end early this evening leaving mostly cloudy skies. continued
weak CAA will drop min readings into the upper 20s inland west to
the mid and upper 30s east.
Wednesday, As the mid level low wobbles into WI the low level trough
is expected to develop over srn or southeastern Lake Superior. 850
mb temps around -2C will provide enough instability (lake temps
around 7C) with the deeper moisture and 700 mb temps to around -11c
for an increase in lake enhanced pcpn into the west half during the
afternoon as winds become nrly. However, there is uncertainty with
how the mesoscale features will evolve and affect pcpn intensity.
Wet-bulb zero heights support mainly snow over the inland west but
a mix of rain and snow closer to the lakes.
&&
.LONG TERM...(Wednesday night through Tuesday)
Issued at 249 PM EST TUE NOV 29 2016
With little potential for significant conditions through the rest of
the week and considerable uncertainty next week, did not make
significant changes to blended initialization. Spent majority of
shift time performing AWIPS fixes.
Without being too specific (see forecast for specific expectations),
the low currently W of the area will move E of the CWA by Wed night
and will meander over Quebec through Fri. The airmass will be cool
enough for some lake enhancement in the N-NW winds behind the
system, so expect off and on precip into Sat, with the best coverage
closer to Lake Superior. Ptype will depend largely on near-SFC
temps, so the best chances for snow will be at night and also over
the higher terrain of the W. Due to only expecting light precip and
with relatively warm SFC temps (at least during the day), only light
snowfall amounts are expected through Sat.
Still looking at a significant pattern change possible 10-14 days
out, with more active weather possible starting later next week.
&&
.AVIATION...(For the 18Z TAFS through 18Z Wednesday afternoon)
Issued at 1241 PM EST TUE NOV 29 2016
Low level moisture wrapping into Upper Michigan from the sw will
maintain mainly MVFR cigs through most of the forecast period.
Troughing developing into the area on Wednesday will support
development of lower MVFR to IFR cigs at SAW. With only light pcpn
forecast, no vsby restrictions are expected.
&&
.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 404 PM EST TUE NOV 29 2016
The low pressure system will linger over the western Great Lakes
into Wednesday. However the pressure gradient is not expected to be
as tight and should allow winds to diminish below 25kt by tonight.
Northerly winds to near 30 knots may develop Thursday as the slow
moving trough moves to the east of Lake Superior into Quebec. High
pressure will then build into the area into Saturday with winds
below 20 knots.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
None.
Lake Michigan...
None.
&&
$$
SHORT TERM...JLB
LONG TERM...Titus
AVIATION...JLB
MARINE...JLB
Area Forecast Discussion
National Weather Service New York NY
341 PM EST Tue Nov 29 2016
.SYNOPSIS...
One weather system departs this evening and another moves in
right behind it for Wednesday with another round of much needed
rain. High pressure returns for late week into the weekend, with
only a weak cold frontal passage on Friday. Another low could
impact the area Sunday night into Monday.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
Heavier rain is ending as 20Z in Jersey and will be ending in the
the NY Metro by 4 PM - an then off the east end by 9 PM (02Z).
Rainfall Totals for today will end up at around are around 1.25"
with some amounts up to 1.5".
Winds peaking up to 30 KT - highest along the coastal plain, but
drop of fast overnight.
Main question for the overnight is how much rain fog do we get?
Fog has always a challenging forecast locally...but the latest
profiles from HRRR and RAP are strongly indicating fog. Will not
issue an advisory - but have gone with the mention of dense fog.
Lows warmer than normal maxes.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT/...
Morning Fog?
Stratiform rain moves in from the west by late morning. A tad
more in instability and thus have included TS for the evening when
LI`s get down to 0.
Another inch or so of QPF. NWP in decent agreement...though may be
on the high end of the QPF.
Temps about the same as today.
Rain exits after midnight.
&&
.LONG TERM /THURSDAY THROUGH TUESDAY/...
Low pressure and cold front move away from the region with surface
high pressure building into the region. Aloft, the upper low will be
centered to our north with a somewhat cyclonic flow over our area.
Expect a breezy day, but still with temperatures above normal as
cold air advection will be weak and gradual on a west flow. Highs
will climb into the middle and upper 50s.
Friday and Saturday will be cooler as temperatures aloft cool. A
weak shortwave moves across the area Friday evening, however it
should pass through the region dry. Not much of a change in the
pattern for Saturday, just slightly cooler. Temperatures on Friday
are expected in the upper 40s and lower 50s. For Saturday, expect
highs in the 40s.
There are still some differences among the global models regarding
the next system to potentially affect the forecast area. Previous
models runs showed a dry forecast from the GFS and a wet forecast
from the ECMWF. The ECMWF continues to trended toward the drier
GFS. In fact, the latest 12z ECMWF keeps conditions dry Sunday night
and Monday. Would prefer to keep at least chance pops in the
forecast to avoid the flip-flop forecasting. So for now, will keep
Sunday dry, but keep the pops in for Sunday night and Monday. Dry
weather is expected on Tuesday.
&&
.AVIATION /20Z TUESDAY THROUGH SUNDAY/...
Low pressure over West Virginia will track through the region
tonight. A warm front will approach the area on Wednesday.
Ceilings and visibility will continue to lower through this evening.
The rain will taper off from west to to east through 23-02Z, with a
period of improvement possible overnight. Fog may develop however
during this period, through approximately 12Z, especially outside of
the city airports.
Additional rain will develop by late Wednesday morning.
Southerly winds will veer to the west tonight. The strongest gusts
will be through 00Z. Winds will back to the southeast again on
Wednesday.
Winds at 2000 ft of around 50 kt can be expected through the early
evening, resulting in low level wind sheer.
...NY Metro Enhanced Aviation Weather Support...
Detailed information, including hourly TAF wind component forecasts,
can be found at: http:/www.weather.gov/zny/n90
KJFK TAF Comments: Ceilings may remain above 1000 ft through 00Z.
KLGA TAF Comments: Ceilings may remain above 1000 ft through 00Z.
KEWR TAF Comments: Occasional gusts to around 25 kt are possible
this evening. Ceilings may remain above 1000 ft through 00Z.
KTEB TAF Comments: Occasional gusts up to 25 kt are possible this
evening. Ceilings may remain above 1000 ft through 00Z.
KHPN TAF Comments: Occasional gusts up to 20 kt are possible this
evening.
KISP TAF Comments: No unscheduled amendments are expected at this
time.
.OUTLOOK FOR 18Z WEDNESDAY THROUGH SUNDAY...
.Rest of Wednesday...IFR with rain. Southerly winds up to 20 kt.
.Thursday...VFR with westerly flow.
.Friday...VFR with westerly flow.
.Saturday...VFR with northwesterly flow.
.Sunday...VFR with northwesterly flow.
&&
.MARINE...
Minimal Gale occurring at this time over the ocean and the south
shore bays....but this will diminish quickly tonight. Seas on the
ocean will remain elevated - thus except a Small Craft Advisory
(SCA) to be posted late this evening once the threat of gales is
over.
Light winds Wednesday morning increase through the day into the
evening with an SCA likely being posted for all waters. The SCA
conditions remain likely on the ocean waters through Saturday as
lingering seas and winds gusts continue. On the non-ocean waters,
some gusts to 25 kt may continue on the eastern sound and bays
into Friday night. Sub-SCA conditions are then expected on the
area waters.
&&
.HYDROLOGY...
Another inch of QPF for Wednesday...generally less than today.
More puddle and poor drainage flooding.
No significant PCPN expected from Thursday through at least Sunday.
A chance of PCPN returns Sunday night into Monday.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...Small Craft Advisory until 7 PM EST this evening for ANZ335-
338.
Small Craft Advisory until 10 PM EST this evening for ANZ330-
340.
Gale Warning until midnight EST tonight for ANZ345-350-353-355.
&&
$$
SYNOPSIS...Tongue
NEAR TERM...Tongue
SHORT TERM...Tongue
LONG TERM...BC
AVIATION...JMC
MARINE...BC/Tongue
HYDROLOGY...Tongue
Area Forecast Discussion
National Weather Service Paducah KY
341 PM CST Tue Nov 29 2016
.SHORT TERM...(Tonight through Thursday night)
Issued at 304 PM CST Tue Nov 29 2016
After a brief respite from the rain today, a cold front, which is
just to our west, will cross the region tonight. Ahead of the front,
weak ripples of energy in the southwest flow aloft will tap into
enough moisture to produce overrunning precipitation mainly over the
southeastern sections of the CWA, mainly west KY up into possibly
southwest IN. While some sprinkles could occur prior to 00Z tonight,
most of the heavier QPF will likely occur after 00Z with the
heaviest rain falling over the southern Pennyrile region.
Models are not in agreement with QPF amounts with the HRRR and GFS
indicating fairly low QPF and the NAM indicating a pretty good
amount of rain from the lakes region eastward, since it is
indicating a sfc low developing along the front to our south that
moves northeast into central KY by 09Z Wed. Definitely think the
best chances for heavier QPF will be from Calloway County KY up
through Muhlenberg County KY and areas south and east of there with
lighter amounts northwestward. In fact, if the NAM is correct parts
of southern Christian county and most of Todd county could see
upwards of a half inch or more.
Instability is hard to come by with this event but the best chance
for thunder will be over parts of west KY, namely from the lakes
region eastward (southern Pennyrile region). Better chances for
severe will be to our east and south, as outlined in the latest SPC
Day 1 outlook, but cannot rule out a strong storm in the far
southeastern areas, especially this evening. Will have to keep a
close eye on extreme southern portions of the Pennyrile region of
west KY. Convection is already ongoing in southern AR and MS heading
north northeast.
In the wake of this system, we will have a pretty tight pressure
gradient in place so breezy conditions will result on Wed. In
addition, clouds will be returning for parts of the area as main
upper trough moves overhead. However, sfc high pressure will
eventually build into the area which will mean dry but cooler
weather will be with us from Wednesday through the end of the
period.
.LONG TERM...(Friday through Tuesday)
Issued at 304 PM CST Tue Nov 29 2016
Most interesting part of the long term will come Saturday night.
Confidence is lagging somewhat, but it looks like some locations
may experience the first very light wintry type precip of the
season. However, no real impacts are anticipated at this time.
Chilly high pressure will be settling in over the region to start
the period on Friday into Saturday, with dry conditions and temps
down close to normal for this time of year. The high will scoot
off to the east Saturday night/Sunday as a weak short wave and
associated trof of low pressure at the surface push east toward
the mid MS River/lower OH Valley regions.
There could be enough isentropic lift generated to produce an
area of light precip later Saturday night into Sunday morning.
While only light rain is expected over far southern portions of
the region (closer to the AR/TN borders), temperatures in the
lower to mid 30s over the remainder of the region could result in
some very light snow, or a rain/snow mix, if the light precip
does not evaporate before reaching the ground. Nonetheless, ground
temps will bed relatively warm, and would mitigate any impacts.
So, some may wake Sunday AM to witness a few flakes of snow, but
that should be the extend of it unless a stronger wave manages to
form as we get closer to the weekend.
After a brief break in precip chances Sunday night/Monday, a
stronger, southern branch system may form toward the end of the
long term over the Southern Plains and then eject northeast word
the region later Monday afternoon or Monday night. ECMWF is much
more potent than the operational GFS with this system, but either
way, conditions will have warmed enough for an all rain event.
&&
.AVIATION...
Issued at 339 PM CST Tue Nov 29 2016
The cold front approaches the area this evening making it through
the terminals between 02-08z. Will go with VCSH as best coverage
looks to be just south and east of the TAF sites. Those venturing
farther south toward KHOP and into TN will need to monitor for
possible thunderstorm development this evening.
&&
.PAH WATCHES/WARNINGS/ADVISORIES...
IL...None.
MO...None.
IN...None.
KY...None.
&&
$$
SHORT TERM...GM
LONG TERM...CW
AVIATION...GM