Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 01/28/20
Area Forecast Discussion
National Weather Service Denver/Boulder CO
856 PM MST Mon Jan 27 2020
.UPDATE...
Issued at 809 PM MST Mon Jan 27 2020
A band of snow showers is moving southeastward across the eastern
plains this evening. This band is heaviest across Lincoln and
southern Elbert Counties and will make for poor travel conditions
on I-70 east of Limon this evening. This band should move out of
our CWA by around midnight with accumulations between 1-2 inches
across the far eastern plains.
Water vapor imagery shows a dry intrusion progressing eastward
across the central mountains this evening. Mid and upper level
clouds have dissipated behind this dry intrusion leaving scattered
low level clouds behind. With the drier air moving in, we
considered canceling the Winter Weather Advisory for the Park
Range. However, the limited observations and webcams that are
available in the area haven`t shown a drastic improvement in road
conditions so the Winter Weather Advisory will be left to expire
at midnight.
Low temperatures across the urban corridor and plains were
increased tonight due to the cloud cover and high relative
humidities. Most areas should see lows in the upper 20s.
&&
.SHORT TERM...(This evening through Tuesday)
Issued at 110 PM MST Mon Jan 27 2020
GOES-16 water vapor showing a well defined vorticity maximum
moving east-north east across south central Colorado. It`s moving
at a fairly good clip with a well-defined edge to the upward
forcing getting ready to move across the Grand valley in western
Colorado. The best synoptic-scale forcing should remain to the
south of our area until the far eastern plains when the northern
edge skirts southern Washington/northern Lincoln Counties. A
frontogenesis band sets up across this area, coincident with the
best QG forcing late afternoon into the evening. The HRRR has
latched onto this feature and generates about a quarter inch of
liquid through midnight across this area. From the Palmer Divide
east and northeast out to about Holyoke, and southeast of there
should be where the best precipitation occurs. 1-3 inches with
the potential for 4 are possible across that area. With road
temperatures currently in the mid 40s, wet and temporarily slushy
roads are the only expected impacts along this band. Elsewhere,
from Denver northward to Wyoming, and north of I-76, precipitation
chances are slimmer. There will be a lot of virga and at times wet
pavement, but the showers will be hit or miss and shouldn`t
amount to much QPE. Roads are plenty warm to just remain wet
through this evening. Do feel that any precip that falls would be
in the form of snow. Best chance is from now through 6 PM.
Further east closer to Kansas, precip may stick around until
midnight.
In the mountains, the snowfall has been light throughout the day
so far after a robust start across the lower elevations of western
Colorado. Area web cams continue to show wet roads across the
highest mountain passes along and in the vicinity of I-70. Can`t
rule out a moderate, brief snow shower through about 10 PM as the
trough axis moves across the area, but at this point travel
impacts should be minor. Additional accumulation of 1-2", maybe 3
are possible until then. Further north across the northern Front
Range and Park Range, orographics and moisture is better but lapse
rates continue to be poor, and getting poorer with time. This
will limit amounts, with the most snow expected across the Rabbit
Ears Pass area, with an additional 3-5" possible through around
midnight.
By late morning Tuesday the trough is in Oklahoma, and the entire
state is under decent subsidence. Skies should clear out and
become mostly clear throughout the day, with no precipitation
expected. Despite the dry northwest flow, some warm advection
will occur throughout the atmospheric column, going from -12 to
-7 degC at 700 mb. Thus, highs will be seasonal in the mid to
upper 40s across the plains, with 20s to near 30 in the high
country. West winds 25G35 mph are possible at and above 10 kft
MSL, but light winds across the I-25 corridor should occur
throughout the day, with some northwest winds across far eastern
Colorado 12G20 mph or so.
.LONG TERM...(Tuesday night through Monday)
Issued at 110 PM MST Mon Jan 27 2020
No significant adjustments planned in the extended period. The next
system will pass mainly to the west and south of the region Wednesday
and Wednesday night with weak mid level QG Omega passing over the
forecast area. A cold front associated with this system will move
across the I25 corridor and northeast plains Wednesday evening,
with weak north to northeast post frontal winds in the low levels.
In the mountains, 24-hr snowfall totals in the 2-5 inch range.
Weak orographic potential Wednesday and Wednesday night as mid
level winds will be light with more of a deformation zone over CO.
The upper trough will be over central AZ/NM by 00Z Thursday and
into old MX by 12z Thursday. Snowfall totals over the foothills
and Palmer Divide, should be light with anywhere from a trace to
2 inches. Generally isolated to scattered snow showers across the
I25 corridor and adjacent plains Wednesday night with no
accumulating snowfall expected. Thursday and Thursday evening,
lingering residual moisture and better mid level winds may allow
for some light orographic snowfall in the mountains along the
higher north/northwest facing slopes but dry elsewhere. Friday
through the weekend, it will be dry and warmer as a ridge of high
pressure builds over the western U.S. The high temperature in
Denver by Sunday could close in on 70 degrees. It will be cooler
on Monday with the next storm system expected to drop northwest to
southeast across the forecast area Monday night into Tuesday.
This system will bring snow to the mountains and could produce
light snow to the i-25 corridor and northeast plains as well.
&&
.AVIATION...(For the 06Z TAFS through 06Z Tuesday night)
Issued at 809 PM MST Mon Jan 27 2020
All precipitation has moved southeast of the terminals this
evening and dry weather is expected through Tuesday. Low level
moisture remains in place as dew point depressions are between 1
to 2 degrees. This will create some haziness with visibilities
possibly dropping to 5 miles from time to time. Ceilings should
stay above 8 kft before a dry intrusion clears skies out around
midnight. Winds at DEN will be tricky as there is low confidence
that northeast winds will develop around midnight. It is possible
weak drainage flow persists through the early morning hours.
Tomorrow, northerly winds will develop before veering easterly
around sunset.
&&
.BOU WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory until midnight MST tonight for COZ031.
&&
$$
UPDATE...Danielson
SHORT TERM...Schlatter
LONG TERM...Cooper
AVIATION...Danielson
Area Forecast Discussion
National Weather Service Boston/Norton MA
959 PM EST Mon Jan 27 2020
.SYNOPSIS...
Dry conditions with a mix of clouds from time to time through
Tuesday. A cold front will cross the region during Tuesday,
bringing a batch of colder air. Ocean effect rain and snow
showers may develop across the eastern waters late Tuesday and
Tuesday night especially near eastern Cape Cod and Nantucket.
Temperatures will be rather mild tonight, but will be much
colder by Tuesday night after the front moves offshore. Dry
conditions with closer to seasonable temperatures for the
remainder of the work week. Still watching for the potential
for a coastal storm which may impact the region for the weekend,
though it remains far from a certainty.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
10 PM Update...
Increased cloud cover overnight. As with the previous update
think it will be tough to shake the cloud cover. May be able to
once a shortwave slides offshore after midnight. Have also
increased overnight low temperatures a few degrees based on the
cloudier forecast.
Previous discussion...
Infrared and nighttime microphysics RGB imagery shows
considerable wrap-around moisture/clouds across much of Southern
New England in cyclonic flow aloft. This cloudiness really extends
northward across a good part of New England and into Quebec as
well. While flow is downslope (WNW/NW), suspect that clouds
will be tough to fully shake free from. Following upward
(moister/more clouds) trends in the 18Z NAM and the past few
runs of the RAP guidance, used those as a basis for increasing
sky cover through overnight areawide, but particularly for
northern and western MA. These results in skies from partly
cloudy to overcast. May be some spotty sprinkles or flurries
falling through the clouds at times, with some snow pellets/snow
grains reported earlier in the Canton CT area; however,
significant sub-cloud dry air with sizable dewpoint depressions
will make any flurries or sprinkles the exception versus the
rule.
I also warmed temperatures up some through early-overnight to
account for the increased cloudiness and continued at least modest
NW winds permitting limited radiational cooling. Most areas
should be at or below freezing in the interior by pre-dawn, and
just above that in RI and eastern MA/Cape Cod. If clouds
linger, current lows in the mid-20s to low-mid 30s may be too
cold and could need an adjustment upward in later forecasts.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH TUESDAY NIGHT/...
Tuesday...
Another mainly dry cold front will shift S out of central New
England during the day. However, short range models are
indicating this front may stall close to or just into the Route
2 corridor of N Mass by late Tuesday morning. Even with the slow
moving, albeit dry, front moving across, colder air will work
in during the remainder of the day as H85 temps drop to -7C to -10C
and H925 temps fall to -3C to -5C by late in the day.
Another question for the day will be whether a band of ocean
effect precip develops as winds veer to N-NW during the
afternoon across portions of the mid and outer Cape as well as
Nantucket. Some question amongst the hi res model suite as to
where the band positions itself as it develops late in the day.
At this point, looks like the band will start off as rain
during the afternoon as temps are forecast in the upper 30s at
around 18Z-19Z. Temps should fall to the mid 30s by 00Z.
Expect partly to mostly sunny skies to start, but clouds will
work southward as the front moves across. Also, as the winds
become northerly, will see the most clouds develop across the
eastern waters, which will move across the Cape and islands
during the afternoon.
Overall, expect temps to top off several degrees cooler than
today, ranging from the 30s across the higher terrain to around
40 elsewhere, but readings will start to fall after 18Z as the
colder air moves southward.
Tuesday night...
As the colder air works across the region Tuesday night, with
H85 readings dropping to -6C to -9C by around 09Z, the coldest
temps will lie across E Mass as well as the Cape and islands.
With these cold temps and the northerly wind trajectory, will
see the ocean effect rain quickly change to snow. Current
forecast suggests this should occur by around 02Z and last
through most of the night before tapering off during the pre
dawn hours. QPF amounts should be around 0.1 inches, highest
across the outer arm of the Cape. Based on this, could see some
light snow accumulations, possibly up to an inch.
Clouds will linger across central and eastern areas as well as
the E slopes of the Berkshires, but could see partly cloudy
conditions from N central Mass through the CT valley into N CT.
Expect lows in the mid teens to around 20 across the higher
terrain to near 30 across outer Cape Cod and Nantucket. These
readings, while still around 5 degrees above normal, will run a
good 5 to 7 degrees below tonight`s lows. With the northerly
winds at around 10 mph, except up to 15 mph or so across the
Cape and islands, wind chill values will drop to the single
digits across the higher terrain to the teens to around 20
elsewhere toward daybreak.
&&
.LONG TERM /WEDNESDAY THROUGH MONDAY/...
Highlights...
* Dry conditions with seasonal to slightly above normal temps
through Fri.
* Still monitoring for a potential storm next weekend, but
uncertainty remains high
Details...
Tranquil stretch of weather for the rest of the workweek as
ridging both at surface and aloft builds across Southern New
England. A weak shortwave trough will dig southward from eastern
Quebec through much of New England during the latter part of
Wednesday; though it will be a dry passage and its only real
influence will be to induce a shot of cooler air (925 mb temps
-8 to -11C per ECMWF, not exactly cold but a colder airmass than
seen recently) for Wednesday night into Thursday. High pressure
then shifts off the coast later Thursday, affording more of a
milder southerly flow Thursday night into Friday.
Overall looking for seasonable temperatures with good diurnal
ranges, with mostly sunny skies during the day and clear/calm
nights. Highs in the mid-upper 30s for Wednesday, with the
coldest day being on Thursday with the cooler thermal profiles
(low to mid- 30s); warming back into the mid 30s to lower 40s
for Friday. Lows on Wednesday and Thursday nights into the teens
to lower 20s; while lows Friday night in the mid 20s to near
freezing.
Saturday into Sunday:
Still a considerable degree of uncertainty on the forecast for
the weekend, as models continue to simulate a coastal low
pressure near the Carolinas on Saturday. While today`s guidance
has shown some tendency for a south/east-of-the-benchmark track,
the exact track and resulting impacts remains uncertain.
Phasing of trough energy in the northern stream (digging south
from the Canadian Prairies) and southern stream (South Texas
into the Gulf Coast states) will prove critical in determining
how close to Southern New England this potential storm system
may get. Today`s deterministic model guidance from the GFS and
ECMWF indicate this phasing occurs late, with resulting
deepening occurring south and east of the 40N/70W benchmark.
These more offshore solutions have some support (a loose
majority) from their respective ensemble members (EPS, GEFS).
This would verbatim bring a glancing blow to the east and
southeast coasts with little if any QPF in the interior, instead
supporting a colder/largely dry northwest flow. Only the
Canadian GEM brings a larger extent of the precip shield back
far enough west to permit some impacts across a larger spatial
area later Saturday into Sunday (on the western end of the
guidance). While today`s guidance indicates a more offshore
track, there does remain a number of members in the 12z GEFS and
12z EPS that are closer to the benchmark; given this and the
evolution of this potential system hinging on aforementioned
phasing, it still is too early to lock into any solution. Lack
of antecedent colder air also opens the door for continued
questions on p-type.
Given the above, and that were are still a good 6 days out with
guidance highly probable to change in subsequent days, think it
is prudent to side the official forecast fairly close to
continuity, with maybe a slight decrease in PoP in the interior
given the SE track. Chances for snow/rain are thus indicated for
all locations. Highs in the mid 30s to low 40s, and lows in the
20s.
Monday:
Some uncertainty exists on Monday depending on how weekend
developments transpire. Most guidance indicates dry conditions
under high pressure, with temperatures remaining near to
slightly above seasonal normals. Were any snowpack to be around,
again contingent on what may happen over the weekend - could
see some pretty chilly overnight lows. Stuck more closely to a
guidance blend for this period.
&&
.AVIATION /03Z TUESDAY THROUGH SATURDAY/...
Forecaster Confidence Levels...
Low - less than 30 percent.
Moderate - 30 to 60 percent.
High - greater than 60 percent.
00z TAF Update:
Short Term...High confidence.
Rest of Tonight:
Leftover lower-level moisture looks to be tough to fully scour
out, resulting in SCT- OVC VFR ceilings (bases 040-060) the
rule for tonight. Greatest coverage furthest north and west.
Winds WNW-NW around 6-12 kt.
Tuesday...
VFR most areas. May see MVFR CIGS develop across the E slopes
of the Berkshires by midday as well as move into portions of E
coastal Mass. Isold -SHSN possible across higher terrain of NW
Mass, and SCT -SHRA across the outer Cape. N-NW winds 10-15 kt,
highest along the E coast.
Tuesday night...
VFR most areas. MVFR CIGS across E slopes of the Berkshires and
E coastal Mass. MVFR VSBYS in mixed SHRA/SHSN through 03Z- 04Z,
changing over to -SHSN across the mid and outer Cape terminals
which should end by around 10Z.
KBOS Terminal...High confidence in TAF.
KBDL Terminal...High confidence in TAF.
Outlook /Wednesday through Saturday/...
Wednesday: VFR.
Wednesday Night: VFR. Breezy.
Thursday through Friday: VFR.
Friday Night: Mainly VFR, with local IFR possible. Slight
chance SHSN.
Saturday: MVFR/IFR conditions possible. Slight chance RA,
slight chance SHSN.
&&
.MARINE...
Short Term /through Tuesday Night/...High confidence.
Through 00Z...W winds 15-20 kt with gusts up to 25 kt. Dry
conditions. Seas 4 to 6 ft on the open waters. Good visibility.
Tonight...NW winds 15-20 kt early, diminishing to around 10 kt
by around midnight. Seas up to 4 to 6 ft on the outer waters
then subsiding after midnight. Dry weather and good visibility.
Tuesday...N-NW winds 10-15 kt. Scattered rain showers during
the afternoon across the eastern waters from Nantucket to Cape
Cod to Cape Ann. Mainly dry elsewhere. Seas lingering at around
5 ft E and S of Cape Cod, otherwise 4 ft or less. Dry weather
and good visibility.
Tuesday Night...N-NW winds becoming N 10-15 kt. Gusts up to 20
kt on the eastern waters. Seas 3 to 4 ft. Scattered rain showers
early, changing to snow showers across the eastern waters from
east of Boston Harbor to near and east of Cape Cod and
Nantucket. Mainly good visibility, except 1 to 3 nm in vicinity
of snow showers.
Outlook /Wednesday through Saturday/...
Wednesday: Winds less than 25 kt. Areas of seas approaching
5 ft.
Wednesday Night through Thursday: Winds less than 25 kt. Local
rough seas.
Thursday Night: Winds less than 25 kt. Seas locally approaching
5 ft.
Friday: Winds less than 25 kt.
Friday Night: Winds less than 25 kt. Slight chance of rain
showers, slight chance of snow showers. Local visibility 1 to
3 nm.
Saturday: Winds less than 25 kt. Chance of rain, slight chance
of rain showers. Local visibility 1 to 3 nm.
&&
.BOX WATCHES/WARNINGS/ADVISORIES...
CT...None.
MA...None.
RI...None.
MARINE...Small Craft Advisory until 10 AM EST Tuesday for ANZ254-255.
Small Craft Advisory until 6 AM EST Tuesday for ANZ256.
&&
$$
SYNOPSIS...Loconto/EVT
NEAR TERM...BL/Loconto
SHORT TERM...EVT
LONG TERM...Loconto
AVIATION...BL/Loconto
MARINE...BL/Loconto
Area Forecast Discussion
National Weather Service Burlington VT
803 PM EST Mon Jan 27 2020
.SYNOPSIS...
Upper low will slowly depart across the Canadian Maritimes
tonight, but will still maintain low overcast conditions and
scattered snow showers overnight. An additional coating to 2
inches of snow will be possible through early Tuesday morning,
and a few icy spots are expected as temperatures fall into the
20s. Thereafter, high pressure will build eastward from
northern Ontario, bringing drier weather and more seasonable
temperatures through the end of the work week.
&&
.NEAR TERM /THROUGH TUESDAY NIGHT/...
As of 803 PM EST Monday...Quick update to introduce
patchy/areas of -dz/-fzdz mixed in w/occnl light snows into the
overnight hours per recent report from eastern Chittenden County
and Pierre-Trudeau Intl in Montreal also reporting very light
-fzra. Model sounding profiles are quite mixed, showing the
dendritic snow growth zone going in and out of a saturated vs.
unsaturated state overnight depending on the solution, though
most recent HRRR output seems to be leaning toward the latter.
Light snow accumulation forecasts were not changed with this
update owing to uncertainty in future coverage of any -dz/-fzdz.
The rest of the forecast in regard to cloud cover, winds,
temperatures etc. also remain unchanged at this point.
Prior discussion...
A moist cyclonic flow prevails across the North Country on the
swrn periphery of departing deep-layer low over the Gulf of St.
Lawrence. A low overcast and periods of light showers will
continue this afternoon through tonight, and 18Z radar trends
indicate an increase in radar reflectivity across nwrn VT nwd
into srn Quebec. PBL temperatures are marginal for snow in the
valley locations, thus continued with the idea of a light
rain/snow mix at times in the St. Lawrence and Champlain
Valleys. As we get past sunset, low-level thermal profiles cool
sufficiently that we should see just snow showers across the
region, and a better chance at some accumulating snow at the
lower elevations. It does appear based on 12Z BTV-4kmWRF that
orographically blocked flow will become an increasing factor
overnight, with Froude Numbers falling below 0.5 along the
western slopes of the Green Mtns after 02Z. This is also
reflected in the NAM-12 forecast sounding at BTV, with a slight
increase in hourly snowfall rates late this evening through
about 12Z Tuesday. Have increased PoPs upwind of the Green Mtns
on the VT side of the Champlain Valley as a result as we head
through the evening hours. Still a minor event overall, with
total snowfall accumulations through 12Z Tuesday of a dusting to
2" in most locations, including 1-2" around BTV and points
east. May see 2-4" across the higher summits of the nrn
Adirondacks and central/nrn Green Mtns. Also, as temperatures
fall into the upper 20s tonight, will see some developing icy
spots, so drivers should exercise caution tonight and into the
morning commute time frame on Tuesday.
On Tuesday, snow showers will taper off to mountain flurries and
a few breaks are expected to develop in the overcast with loss
of cyclonic flow aloft and diminishing mid-level moisture. NW
winds of 5-10 mph expected overnight into Tuesday bring modest
low-level CAA, and temperatures several degrees colder for
Tuesday. Highs are expected in the upper 20s to lower 30s.
Surface high pressure builds ewd across northern Ontario on
Tuesday night. Should result in a quiet night across the North
Country. Lows mainly in the teens, but single digits above zero
are expected across the northern Adirondacks and far nern VT.
&&
.SHORT TERM /WEDNESDAY THROUGH WEDNESDAY NIGHT/...
As of 245 PM EST Monday...A 1030 mb surface high will sink south
across the North Country on Wednesday which will cut off any
lingering light snow showers along the higher terrain. Although this
high pressure has origins over northern Hudson Bay in Canada, the
cold air remains locked up in the arctic which will keep afternoon
high temperatures on Wednesday right around normal with readings in
the lower to upper 20s. Wednesday night, however, looks on the
chilly side as the surface and boundary layer will decouple shortly
after sunset which will allow winds to become light and variable
while skies continue to clear. Overnight lows in the single digits
above and below zero are expected, with the coldest temperatures
expected across the Adirondacks and Northeast Kingdom. Some of
the hi-res guidance shows 10-15 knots of due northerly flow
right off the deck Wednesday night which could create some lake
induced clouds across parts of the Champlain Valley given the
lack of ice coverage on Lake Champlain. This could cause
temperatures in a few locations to remain in the teens overnight
with the possibility of a few flurries but otherwise should
have little impact on the forecast.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
As of 245 PM EST Monday...High pressure will remain entrenched across
the North Country on Thursday and Friday with mostly sunny skies
expected across the region. The air mass underneath the high
pressure system will continue to moderate with high temperatures on
Thursday in the lower to upper 20s and in the mid 20s to mid 30s on
Friday. Overnight lows will be a bit warmer Thursday night with
lows in the single digits above zero and in the teens Friday
night. The next chance for any type of measurable precipitation
won`t occur until Saturday afternoon as a complicated system
approaches the region as high pressure departs to the northeast.
There will be two separate waves of energy with the first
forming over the Gulf of Mexico and the second developing over
the Mid-West. The Gulf of Mexico system will likely be the
stronger of the two systems but it looks like it`s going to pass
well to our south and east into the Atlantic. There is some
uncertainty amongst some of the ensemble members but the
majority show this system pushing east of benchmark which would
follow the pattern so far this winter with both positive NAO and
AO currently being observed. This would likely keep us as
spectators as all precipitation would likely be east of Vermont.
The second wave will move across the Mid-West Saturday morning
and track into New England Saturday night/Sunday morning. This
wave will be enhanced by a closed 500 mb low that will help
bring the return of some snow showers. Moisture will be
extremely limited with the first system over the Atlantic
shunting the majority of the moisture offshore. Nevertheless, it
looks like 1-4 inches of snow will be possible with the highest
amounts along the western slopes of the Adirondack and Green
Mountains. The upper level trough will swing through Monday
with upper level ridging building in Monday night into Tuesday.
High temperatures will continue to moderate over the weekend
with temperatures on Sunday warming into the lower to mid 30s
across all of the North Country.
&&
.AVIATION /01Z TUESDAY THROUGH SATURDAY/...
Through 00Z Wedesday...Mainly OVC skies expected over the next
24 hours under light north/northwesterly flow in the 3-7 kt
range. Cigs to range mainly MVFR to VFR, though some occnl IFR
in light snows/snow showers likely to occur here and there
through the evening/overnight hours, mainly at KBTV and KSLK.
After 18Z Tuesday a gradual trend toward VFR at valley sites of
KMSS/KPBG/KBTV expected.
Outlook...
Tuesday Night: Mainly VFR, with local MVFR possible. NO SIG WX.
Wednesday: VFR. NO SIG WX.
Wednesday Night: VFR. NO SIG WX.
Thursday: VFR. NO SIG WX.
Thursday Night: VFR. NO SIG WX.
Friday: VFR. NO SIG WX.
Friday Night: VFR. NO SIG WX.
Saturday: VFR. NO SIG WX.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...None.
NY...None.
&&
$$
SYNOPSIS...Banacos
NEAR TERM...JMG/Banacos
SHORT TERM...Clay
LONG TERM...Clay
AVIATION...JMG
Area Forecast Discussion
National Weather Service Goodland KS
740 PM MST Mon Jan 27 2020
.UPDATE...
Issued at 740 PM MST Mon Jan 27 2020
Light snow is falling generally along and west of the CO/KS border
north of the interstate as a weather disturbance approaches. Snow
will expand in coverage from west to east with visibilities as low
as one mile. Latest available guidance is advertising snowfall
totals of 2 to 3 inches for all but the far east and southwest
portions of the area. WPC showing 40 to 70 percent chance of at
least 2 inches. Felt it was best to get an advisory out despite
being potentially a marginal event. Luckily winds will be light.
Low temperatures in the mid to upper 20s.
&&
.SHORT TERM...(This evening through Tuesday night)
Issued at 318 PM MST Mon Jan 27 2020
The main forecast concern in the short term period is on snowfall
amounts tonight through early Tuesday morning.
With temperatures across the north and east remaining cooler today
than previously expected, and warmer than expected over the far
southwest, the distribution of rain/snow as it initiates across
the forecast area has been modified somewhat from previous
forecasts. Widespread snow amounts ranging mostly from 2 to 3
inches are now expected between tonight and mid day Tuesday with
localized max snowfall amounts around 3 inches showing up along a
line extending from central Yuma county to Gove county.
The HRRR earlier this morning was advertising much higher total
snowfall amounts over northeast Colorado, which was concerning and
bore watching, but was also somewhat of an outlier. That max area
has since diminished somewhat and traveled more eastward over
northwest Kansas, which is more in line with what the larger scale
models were showing in their latest runs. Confidence in
measurable precipitation is high and is reflected in the area of
definite PoPs that traverses the CWA tonight, but the total
precipitation and snowfall amounts are still somewhat lacking in
confidence. As a result, confidence was still not high enough in
snow amounts of 3" or greater to need an Advisory. Localized
amounts of 3 are still possible, although the snow probability
graphics are still showing 25th to 75th percentile snow amounts of
T-3" across a large part of the forecast area with no location
coming up with more than 3".
Snow should be done in Colorado around midnight tonight with
locations over Nebraska and Kansas continuing through Tuesday
morning, diminishing from west to east through the morning. As
light snow continues over the far eastern sections of the forecast
area around mid-day on Tuesday, there is a possibility of the
light snow changing back to light rain before it diminishes
completely. Dry conditions are expected beyond Tuesday afternoon
with some clearing Tuesday night. As skies clear, there is a
possibility of some areas seeing fog develop, especially over
areas of fresh snow cover. Confidence in any one area will depend
heavily on sky cover, which is low right now, so did not end up
introducing any fog at this time Tuesday night into Wednesday
morning.
.LONG TERM...(Wednesday through Monday)
Issued at 202 AM MST Mon Jan 27 2020
The extended forecast will remain mainly dry with unseasonably warm
temperatures. A deamplifying upper ridge over the High Plains
will move east through the day Wednesday with an upper trough
extending from the western part of the Dakotas to southwest of the
Four Corners region. High temperatures will range from the mid to
upper 40s and lows will range from the upper teens to mid-20s.
Thursday, a cutoff low will develop south of the Four Corners region
with split flow setting up. The southern trough will be situated
over Northern Mexico while the upper split will be over the Tri-
State area. The pattern will become a little more active as an
upper level shortwave trough embedded in the trough will progress
east. A second shortwave trough will move through the Tri-State
region Thursday night into Friday morning with northwest flow
aloft over the region. Dry conditions will persist Thursday and
Friday with a gradual warming trend heading into the weekend. High
temperatures will range from the upper 40s to mid-50s on Friday.
Saturday and Sunday, a ridge over the Western U.S. will shift east
into the region. Warmer temperatures are expected across the
region through the weekend. Saturday temperatures will range from
the mid-50s to low 60s for highs and upper 20s to mid-30s for
lows. Sunday highs will range from the mid-60s to low 70s.
Relative humidity values are expected to be in the teens to low
20s in Eastern Colorado in the afternoon. Sustained winds at this
time will be around 10-15kts. With the low RH values, dry
vegetation in the region, warm temperatures, and marginal winds,
Sunday afternoon will need to be monitored in the coming days for
possible fire weather concerns.
Monday, a cold front will move through the region. Temperatures
will be much cooler, ranging from the upper 40s to mid-50s. Monday
night holds a very slim chance for moisture as a mid-level trough
approaches the area.
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 440 PM MST Mon Jan 27 2020
KGLD, sub vfr cigs/vis expected with light snow from around 02z-
13z as a weather disturbance moves through the area. Winds
generally from the east at speeds of 10kts or less. After 14z sub
vfr cigs are expected through about 18z with winds becoming
northwest and increasing with gusts around 25kts expected. After
19z vfr conditions expected with northwest winds continuing to
gust in the 25-30kt range.
KMCK, sub vfr cigs/vis expected through about 20z. Light snow
expected from around 03z-15z with some fog through 19z. Winds
generally under 10kts. After 21z vfr conditions are expected with
northwest winds near 10kts.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...Winter Weather Advisory until 8 AM MST /9 AM CST/ Tuesday for
KSZ001-002-013>015-027>029-042.
CO...Winter Weather Advisory until 8 AM MST Tuesday for COZ090-091.
NE...Winter Weather Advisory until 8 AM MST Tuesday for NEZ079.
&&
$$
UPDATE...99
SHORT TERM...LOCKHART
LONG TERM...AW
AVIATION...99
Area Forecast Discussion
National Weather Service Grand Rapids MI
723 PM EST Mon Jan 27 2020
LATEST UPDATE...
Aviation
.SYNOPSIS...
Issued at 318 PM EST Mon Jan 27 2020
- Chance of snow showers late tonight and Tuesday
- Fairly quiet this week with occasional light precipitation
&&
.DISCUSSION...(This evening through next Monday)
Issued at 318 PM EST Mon Jan 27 2020
-- Chance of snow showers late tonight and Tuesday --
A 500 mb vorticity maximum and 850 mb cold pool over northwestern
Ontario will dive through Michigan late tonight into Tuesday.
This should allow boundary layer inversion heights to increase and
cool off just enough for lake-enhanced snow showers to increase
tonight into Tuesday. The DGZ will remain unsaturated above the
inversion, so substantial snow amounts are unlikely and flake size
should be rather small. Global models are wringing out a few
hundredths of an inch of QPF by Tuesday evening west of US-131,
while the NAM-3km and HRRR are depicting narrow swaths of QPF
around 0.10 inches where bands of showers train downwind of a
shoreline convergence zone. We can`t rule out that amount of
precipitation, but a majority of locations won`t see that much.
This translates to a thin coating of snow and mainly west of
US-131 but locally a half to 3/4 inch of snow. Surface
temperatures will be marginally cold enough to support snow and
slick spots Tuesday morning, then marginally warm enough to
promote melting in the afternoon. Showers should end Tuesday
evening as shortwave ridging re-establishes and surface winds
shift northeast.
-- Fairly quiet this week with occasional light precipitation --
No significant sources for precipitation are present much of this
week, as upper level flow is split and weak over the region and
low- level baroclinicity is weak. There are several upper level
shortwaves within this flow regime, though their reflection on the
surface is minimal, and they seem to mainly serve as a lift to
the dry air in the midlevels, which results in little tangible
weather occuring at the surface. Precip chances will increase by
the weekend as an energetic north Pacific jet propagates into
North America and an amplifying Alberta-clipper-like trough digs
into the Great Lakes.
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 718 PM EST Mon Jan 27 2020
Low clouds will remain in place for the forecast period as little
motion in the extensive cloud shield over the Great Lakes Region
is expected. There were some holes in the shield...but any breaks
should not last long. Some lowering of the bases is expected
overnight...so the IFR could increase somewhat...but for the most
part...MVFR ceilings should prevail. We will need to monitor the
light snow/drizzle risk. Radar shows a few patches of
precipitation dropping down from the northwest and but not many
sites show that it is reaching the ground.
&&
.MARINE...
Issued at 318 PM EST Mon Jan 27 2020
Generally 1 to 3 ft waves are expected today into Tuesday and
fairly calm conditions continuing through mid-week. Northwest
winds up to 15 knots are expected through Tuesday. The next chance
of conditions hazardous to small craft should hold off until at
least Friday or the weekend.
&&
.HYDROLOGY...
Issued at 318 PM EST Mon Jan 27 2020
River levels remain well above normal (90th percentile) for January,
with several still above bankfull but short of flood stage. This
week`s weather is favorable for allowing rivers to crest and begin
falling without much incident. While not much snow is on the ground
in the Grand/Kalamazoo basins, the amount of water that is locked up
in the snowpack is quite substantial (1 inch of water per 2 inches
of snowpack). A slow meltoff during the week should reduce the rate
of fall of the rivers, keeping levels well above normal as we head
into February.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...None.
LM...None.
&&
$$
SYNOPSIS...CAS
DISCUSSION...CAS
AVIATION...MJS
HYDROLOGY...CAS
MARINE...CAS
Area Forecast Discussion
National Weather Service Baltimore MD/Washington DC
909 PM EST Mon Jan 27 2020
.SYNOPSIS...
A couple of weak disturbances will cross the region in northwest flow
through Wednesday morning. High pressure will build over the
northern Great Lakes during the middle of the week as a cold front
drops south from New England and low pressure passes well to the
south near Georgia. A larger area of low pressure may approach
from the Southeast U.S. Friday night into Saturday.
&&
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
The main forecast updates tonight revolve around cloud cover in
the moist northwest flow, with nearly-solid overcast extending
into Canada and back to the northern Plains. A shortwave
trough/vorticity axis is pivoting across the area this evening.
After that passes, it`s possible there`s enough subsidence to
allow some clearing with south/eastward extent (with more of a
downslope influence as well). However, am not convinced we
return to totally clear skies any time soon, especially given
RAP RH cross sections. Will be taking a look to see if low
temperatures need to be adjusted upward any as a result, not to
mention there could be a slight surface wind remaining through
the night.
Other than a brief sprinkle, and precipitation should be limited
along/west of the Allegheny Front in the upslope regime.
Moisture depth is shallow, so accumulations should be minor. It
also may mean there could be a bit of freezing drizzle/mist, but
do not foresee widespread travel impacts at this time.
&&
.SHORT TERM /6 AM TUESDAY MORNING THROUGH WEDNESDAY NIGHT/...
In general, high pressure will be building toward the area
through the middle of the week. Embedded in northwest flow ahead
of the high, however, will be another weak disturbance Tuesday.
Drier air squashes any threat for precipitation east of the
mountains (with minimal chances along the Allegheny Front).
Due to the continued northwesterly winds, temperatures should
trend closer to, if not slightly below normal Tuesday through
Wednesday night thanks to a dry backdoor cold front.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
High pressure should keep conditions cool and mainly dry
Thursday through Friday, though a disturbance passing to the
south could bring some light precipitation to the Allegheny
highlands/I-81 corridor Thursday.
A low pressure system over the Southeast U.S. could impact the
region Friday night through Saturday night. Confidence remains
low at this time as to the scale of impact. The later model
guidance suggests some wintry precipitation moving into the
region Friday night and Saturday morning, then a secondary low
pressure system from the west bringing a chance for a mix of
rain and snow showers Saturday afternoon into Saturday night.
The exact track of either or both of the low pressure systems
remain highly uncertain.
The possibilities of a wintry impact range from a weak system
suppressed far to our south with little to no precipitation across
the region, to a major coastal low tracking either along the coast
or out to sea. For now, we have low end chances for precipitation
advertised throughout the weekend. We will monitor trends in the
guidance throughout the week and gradually focus in on a solution as
we move closer to the event.
For Sunday through Monday, it appears no matter what the track
and outcome of the low pressure systems are, a milder and drier
pattern appear to be in store with high pressure becoming
established farther to the east in the U.S.
&&
.AVIATION /02Z TUESDAY THROUGH SATURDAY/...
VFR ceilings FL040-080 will likely continue through much of the
night and could occur at times through Tuesday in a moist
northwest flow regime. There is a low chance (probably less than
20%) of brief MVFR conditions late tonight into Tuesday
morning, mainly at MRB. It does seem like wind gusts should be
diminishing for the night now, but will pick up again and gust
to 15-20+ knots mid-morning (14-15Z) Tuesday.
VFR conditions are expected for Tuesday night through Friday
night with NW flow becoming NE by late Thursday, generally at or
below 10 knots.
&&
.MARINE...
Northwesterly winds continue across the waters. There has been a
a surge this evening with numerous (but generally brief) gusts
up to 20-25 knots. It does appear the narrower waterways are
beginning to stabilize nocturnally, confirming the brevity of
the event. Will have to keep an eye on the wider waters for
potential adjustments to the advisory, but will otherwise let
the conditions described below prevail.
A weak disturbance will cross tonight, and with air
temperatures cooling that component of mixing will not be as
much of a factor. Therefore, anticipate more widespread/frequent
gusts in excess of 20 knots from late this evening through
Tuesday morning. The more sheltered waters of the middle and
upper tidal Potomac River, Baltimore Harbor and the northern tip
of the Chesapeake Bay may not have gusts quite as high or
frequent due to narrower trajectories over water, so have opted
to leave them out of the advisory for now. Winds may see a brief
uptick over all marine zones right after daybreak Tuesday
before the wind field diminishes Tuesday afternoon.
A second weak disturbance will cross tomorrow evening. Although
the attendant wind field will be weaker, more of a northerly
channeling component to the low-level flow could result in
gusts in excess of 20 knots over the wider waters of the
Chesapeake Bay.
Sub-SCA conditions are expected Wednesday through Friday night.
&&
.LWX WATCHES/WARNINGS/ADVISORIES...
DC...None.
MD...None.
VA...None.
WV...None.
MARINE...Small Craft Advisory from 3 AM to noon EST Tuesday for ANZ531-
532-539-540-542.
Small Craft Advisory until noon EST Tuesday for ANZ533-534-537-
541-543.
&&
$$
SYNOPSIS...DHOF
NEAR TERM...ADS
SHORT TERM...DHOF
LONG TERM...KLW
AVIATION...ADS/KLW/DHOF
MARINE...ADS/KLW/DHOF
Area Forecast Discussion
National Weather Service Marquette MI
534 PM EST Mon Jan 27 2020
.SHORT TERM...(This evening through Tuesday)
Issued at 401 PM EST MON JAN 27 2020
WV imagery and RAP analysis indicated a split flow pattern with the
northern Great Lakes dominated by a relatively weak northern stream.
A mid/upper level ridge was building over the central Great lakes
but a shortwave trough or compact mid level low was sliding sse
through northwest Ontario toward Lake Superior. At the surface,
weak northerly flow prevailed between a ridge over the Eastern
Plains and a low near the Canadian Maritimes. Even with a shallow
moist layer to near 5k ft and 850 mb temps only around -8C, mainly
snow has been observed.
Tonight, as colder air (850 mb temps dropping to around -11C) and
slightly deeper moisture arrives with the upstream shrtwv, expect
light lake enhanced snow to increase for nnw flow favored
locations. However, with only marginal instability, any
accumulations will remain light, generally around an inch or less.
With clouds lingering, look for min temps above guidance, from
around 20 inland to the mid 20s near the Great Lakes.
Tuesday, as the shrtwv over eastern Lake Superior early slides off
to the southeast, expect the light northerly flow lake enhanced
snow to diminish by afternoon. 850 mb temps around -11C should
still support enough ice nuclei to minimize any fzdz chances. Less
than an inch or additional accumulation is expected. Otherwise,
under cloudy skies temps will remain near highs from recent days
in the upper 20s to around 30.
.LONG TERM...(Tuesday night through Monday)
Issued at 258 PM EST MON JAN 27 2020
For those longing for colder, more "winter-like" temperatures we`re
going to have to wait at least one more week. While we will have a
very minor cool down through mid-week, overall temperatures are
expected to remain 5 to 10 degrees above normal for this time of
year. Through mid-week daytime highs look to top out in the mid to
upper 20s, with a warming trend towards above freezing throughout
the weekend. As for overnight lows, the coldest nights/pre-dawn
temperatures look to be Tuesday night and Wednesday night as
temperatures look to fall into the single digits across the far east
and the interior west, elsewhere temperatures will probably only
fall into the teens. Much like the daytime highs, overnight lows
will gradually warm into the 20s throughout the weekend.
Overall, precipitation chances look slim through mid-week, perhaps
some light freezing drizzle/snow showers Tuesday night across the
north. Wednesday through Thursday night looks dry as the tail-end of
surface ridging, associated with high pressure centered in Ontario
pushes northeast into Quebec. There could be some clearing of skies
across the far east on Wednesday, as drier, downsloping easterly
winds briefly becomes established off of Canada. Otherwise, expect
the cloudy conditions to persist. A shortwave arrives on Thursday,
but overall there doesn`t look like much in the way of good moisture
to produce anything other than maybe some flurries. Opted to not
include mentions of flurries in the forecast that far out though.
Lingering sheared out vorticity than lingers into Friday across the
region, with a stronger shortwave digging south across the Midwest.
As this next wave tracks across the region, warm air advection will
increase Friday into Saturday, so we could see some very light snow
develop late Friday into Friday night. Then, another shortwave is
progged to dig south across the region, bringing better chances for
widespread light snow Saturday into Sunday. Overall, these waves
look to be removed from any deeper, moisture (esp. those coming up
and over the Rockies), so not expecting any high-impact snow events
to end the week, just overall light snow.
Sunday into Monday, another wave looks to dig south across the
region, but the placement and timing of this wave will need to be
monitored to determine if any additional precipitation will be
possible. With a highly amplified ridging looking to build into the
region quickly behind this shortwave that could end up shutting down
precipitation chances a bit sooner than currently reflected in the
forecast, or at a minimum keep any lingering chances for
precipitation for late weekend/early next week more closely tied to
any shallow, upslope/onshore flow from Lake Superior.
Continuing to look out a bit further, the upper-level pattern
remains highly amplified across the CONUS as longwave troughing
tracks across the central CONUS by middle parts of next week. This
will favor a transition from the above-normal temperatures to what
will likely end up being below-normal temperatures for the middle of
next week. How long this colder air will hold on, remains to be
seen. Will need to monitor the potential for any impactful winter
weather and winds during this transition, depending on where the
resulting surface low tracks and if we will be warm enough aloft to
create p-type issues. However, this pattern would favor the return
of lake-effect snow to some of our snow belt areas, especially given
the lack of overall ice on the big lake.
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 533 PM EST MON JAN 27 2020
Persistent low level moisture over the region will result in mainly
MVFR conditions for most of the forecast period which is the highest
category that it has been in a while. Upslope northerly flow will
also continue to support some light snow.
&&
.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 401 PM EST MON JAN 27 2020
Winds expected to remain light, at or below 20 knots through the
forecast period.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
None.
Lake Michigan...
None.
&&
$$
SHORT TERM...JLB
LONG TERM...Ritzman
AVIATION...07
MARINE...JLB
...Updated Aviation Forecast Discussion...
.DISCUSSION...
Issued at 329 PM CST Mon Jan 27 2020
Large scale pattern consisting of an upper ridge situated over
the High Plains with a shortwave trough following close behind
over the the northern/central Rockies. Meanwhile, extensive cloud
cover was seen across the region. Surface high pressure was in
control across the Central Plains.
Tonight through Tuesday morning
Latest HRRR and RAP are advertising that the thick cloud cover will
hang on tight through the overnight period over the region.
Tuesday afternoon and evening
Aforementioned shortwave trough currently over the northern/central
Rockies will across the Central Plains and be the focus for precip
activity. Bufkit soundings indicate that the column will be cold
enough for the dominate precip type to be snow. However, given
that moisture will be lacking, amounts will be on the light side
with an inch or less expected.
Wednesday through Sunday
Dry conditions will prevail as an upper ridge builds in. This will
allow for a decent warming trend with highs going from the upper
20s/low 30s on WEdnesday to the mid 40s/low 50s by next Sunday.
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 531 PM CST Mon Jan 27 2020
MVFR ceilings will continue through this TAF cycle with some
patchy fog possible, reducing visibilities to IFR at times.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...None.
IA...None.
&&
$$
DISCUSSION...DEE
AVIATION...Kern
Area Forecast Discussion
National Weather Service Riverton WY
415 PM MST Mon Jan 27 2020
.SHORT TERM...(This evening through Tuesday night)
Issued at 307 PM MST Mon Jan 27 2020
KRIW radar imagery showing persistent area of light to moderate snow
shifting south and east from the southern Bighorn Basin. HRRR has a
decent handle on the progression of this snow, moving it out of much
of Fremont County between 3 and 4 PM. Attention will then shift to
Natrona and Johnson counties where light to moderate snow is
anticipated to continue to increase through about sunset. Shortwave
energy within an upper trough traversing the northern Rockies will
lend support. Div-Q fields still show weak lift across the I-25
corridor Monday evening. Thus, the snow will linger longest over far
eastern Natrona County before winding down between 7 and 9 PM.
Clearing that has occurred over the lower elevations west of the
Continental Divide will progress east later Monday evening. One bit
of concern with this scenario will be the melting snow Monday
afternoon contributing to increased boundary layer moisture.
Decreasing clouds would allow for better radiational cooling and
the possible development of valley and basin fog. For now, will go
ahead and add patchy fog to the overnight and Tuesday morning
forecast.
Shortwave ridging will replace the departing trough by Tuesday
morning. Upper flow backs to the southwest allowing for the return
of Pacific moisture ahead of the next incoming trough. Weak
isentropic lift will begin in the west late Tuesday morning with
mainly light snow over the mountains. The isentropic lift will peak
Tuesday afternoon and early evening with the snow spreading across
the western valleys too. Locations east of the Continental Divide
will see dry conditions with a pressure gradient favoring 20 to 30
mph southwest wind in central Wyoming. Shortwave energy and dynamics
will then dominate through the late evening and overnight as the
isentropic lift wanes. Cold air advection will bring 700mb
temperatures down to around -10C/-11C by 12Z/Wednesday across the
west. This will enhance snowfall production in northwest flow aloft.
Cyclonic flow at 700mb and a weak frontal boundary should be enough
to generate areas of light snow in the northern Bighorn Basin.
Southwest Wyoming bears watching as the energy within the
approaching trough may take a track to our southwest that would
favor the potential for snowfall in that region. Therefore, have
increased snow chances across the far south and far north early
Wednesday morning. Temperatures will be seasonal for many areas
through the short term. Warmer than average temperatures are again
likely in the eastern foothills of the Absaroka and Bighorn ranges
and the snow-free areas of the Bighorn Basin Tuesday afternoon.
.LONG TERM...(Wednesday through Monday)
Issued at 307 PM MST Mon Jan 27 2020
The next round of snow will be moving east of the Divide by
Wednesday morning. Additional accumulations on Wednesday west of the
Divide will be minor, while areas east will see up to an inch or so.
Locally higher amounts are likely (especially in the Bighorns and
Casper Mountain) but nothing significant is expected from this
system.
The messy upper flow pattern will continue through the end of the
week, with another embedded shortwave likely bringing more snow to
western Wyoming on Thursday. Models continue to suggest modest
ridging will set up by the weekend which would bring a reprieve from
the snow. In fact, 700mb temperatures are currently progged to be in
the 0 to +6C range during the weekend. This would likely mean many
locations would see their warmest temperatures of the year so far,
especially in Johnson County where temperatures could approach
60F. As is usually the case in warmer winter days, wind would also
be a factor in this scenario. Additionally, the GFS has now come
into agreement with the ECMWF on not only the warmer/windy
weekend, but on a widespread winter event beginning early Monday.
This would be in the form of a strong cold front sweeping into
the area, and with northwest flow/favorable jet dynamics both
sides of the Divide would have a good chance of significant
snowfall.
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 408 PM MST Mon Jan 27 2020
West of the Divide...KBPI/KJAC/KPNA/KRKS Terminals
Conditions have improved across western terminals, although some
light snow will linger in the mountains tonight with partial
mountain obscurations possible. The next system will move in to
far western Wyoming after 20z Tuesday.
East of the Divide...KCOD/KCPR/KLND/KRIW/KWRL Terminals
Conditions have improved at most terminals, although snow and low
ceilings are expected to continue at KCPR through around 03z. A
gusty wind will develop at KCPR after 17z Tuesday.
&&
.FIRE WEATHER...
Issued AT 307 PM MST Mon Jan 27 2020
Accumulating light snow will persist into Monday evening across
central Wyoming. Elsewhere, conditions will become drier as a trough
of low pressure shifts to the east of the region. These dry
conditions will prevail through Tuesday evening east of the
Continental Divide. To the west, Pacific moisture will begin to
spread into the Teton and Yellowstone dispatch areas by midday
Tuesday. The heaviest snow is likely to fall from mid-afternoon
Tuesday through sunrise Wednesday. Mountain snowfall will generally
range from 3 to 6 inches with up to around 8 inches in the Teton
Range. This weather system will push east of the Continental Divide
late Tuesday night with light snow spreading into the northern
portions of the Cody and Casper dispatch areas as well as
southwest Wyoming. Drier conditions arrive for all areas by
Wednesday night. Gradually warming temperatures are anticipated
through the weekend with readings well above normal in the Bighorn
Basin and Johnson County. The next chance for widespread snowfall
comes next Monday as a weather system brings moisture and colder
air to the forecast area. Smoke dispersal will be best over the
weekend given the warm temperatures and the likelihood of
increasing west wind, especially Sunday.
&&
.RIW WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...CNJ
LONG TERM...Myers
AVIATION...Myers
FIRE WEATHER...CNJ
Area Forecast Discussion
National Weather Service Tampa Bay Ruskin FL
820 PM EST Mon Jan 27 2020
.UPDATE...
Latest RAP and surface analysis shows a closed surface low about
80 or so miles west of Tampa. A stalled frontal boundary extends
across Central Florida. Low-level southwest flow is resulting in
weak isentropic upglide along this boundary, leading to low-topped
sprinkles north of the I-4 corridor. These will dissipate by
midnight as the low drifts southeast and drier, northerly wind
prevail across much of the area. The dense cloud cover will shift
farther south as the low approaches SW Florida overnight. A
sprinkle also cannot be ruled out across this area but overall
very low chances. Otherwise, slightly warmer and drier conditions
are expected tomorrow with highs in the 70s... Very minimal
changes were needed to the ongoing forecast tonight.
&&
.AVIATION...
00Z Issuance... VFR expected with the exception of southern
terminals where lower CIGS are possible through the overnight
hours, causing periods of MVFR conditions. Winds out of the
northeast generally AOB 7 knots.
&&
.MARINE...
An isolated sprinkle or two over the waters through remainder of
the evening. As the low moves southeast over the Peninsula,
northeast winds will briefly reach cautionary levels overnight
across the central offshore waters... A second weak surface low
will move across the northeast Gulf waters late on Wednesday with
a chance for showers possible. A stronger low will move into the
region Friday into Saturday with marine hazards possible,
especially behind the system as high pressure builds in across the
Gulf.
&&
.Preliminary Point Temps/PoPs...
TPA 54 70 53 72 / 30 0 0 30
FMY 57 75 56 75 / 10 0 0 10
GIF 53 71 49 75 / 30 0 0 20
SRQ 54 73 54 74 / 20 0 0 20
BKV 48 72 46 74 / 30 0 0 30
SPG 54 69 54 71 / 30 0 0 30
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...None.
Gulf waters...None.
&&
$$
UPDATE/AVIATION/MARINE...42/Norman
UPPER AIR/DECISION SUPPORT...29/Delerme