Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 02/23/17
Area Forecast Discussion
National Weather Service Wakefield VA
959 PM EST Wed Feb 22 2017
.SYNOPSIS...
A weak trough of low pressure crosses the area through this
evening. Low pressure tracks east across the Florida Peninsula
tonight through Thursday morning. Meanwhile, high pressure
shifts farther off the Mid-Atlantic coast. A strong cold front
crosses the local area late Saturday.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
Latest radar trends and observations indicate ongoing light
rain/drizzle across southern and southeastern Virginia. RAP
guidance places the associated vorticity maxima across southeast
Virginia. As depicted by an overall downward trend in coverage,
the upper level support is expected to wane by midnight as the
energy pushes offshore. Coverage late tonight expected to be
limited to far southeast Virginia and remain light. Rainfall
totals for the day have only totaled a few hundredths of an
inch. BUFR soundings and small dewpoint depressions indicate
rather moist low levels, so anticipate some patchy fog from the
Piedmont into central Virginia overnight, even under a mostly
cloudy to cloudy sky. Otherwise, near term guidance handling
temperatures well, so no additional changes made.
Previous Discussion...
A weak wave of low pressure aloft will cross the local area
thru this evening. Meanwhile, strong low pressure over the
eastern GOMEX will impact the FL Peninsula tonight. As the weak
trough pushes SE of the area, light shwr activity will continue
across the lower 2/3rds of the FA. Have highest pops (40-50%)
straddling the Hwy 460 corridor across the Piedmont thru 6 pm or
so then this shower activity will tend to dissipate/end thru
midnight while drifting slowly SE. Generally remaining mostly
cloudy overnight with lingering low level moisture. Cannot rule
out patchy fog as well early Thu morning, especially along/west
of I-95. Lows temps in the upr 40s to low/mid 50s.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH SATURDAY/...
A high pressure ridge will extend west from its center near
Bermuda Thursday and Friday as heights build aloft due to an
upper ridge expanding NE from the western GOMEX. Meanwhile, the
aforementioned upper low near FL will move east of the Bahamas
Thursday afternoon then heads NE well offshore into Friday.
Expecting generally dry and warm conditions during
Thursday/Friday although there are some model differences wrt
how much moisture gets trapped across the area on Thursday for
possible sprinkles/isold shwrs. Partly to mostly cloudy both
days. Some record highs will be challenged Thursday but Friday`s
numbers appear safe since they are higher. See CLI section
below. Low level thicknesses and H85 temps support highs both
days in the low to mid 70s west of the Ches Bay (possibly upr
70s Fri), 65-70 along the coast. Lows in the upr 40s to mid 50s.
12z models are still in good agreement showing a strong cold
frontal passage between 20Z Sat and 03Z Sun. Data continues to
support a swath of moisture and marginal instability with the
boundary but with the best forcing/dynamics staying north of
the local area. However, given the spring-like conditions
expected ahead of the front (sfc temps in the 70s with 55-60
degree dew points) along with some instability present and
moderate shear, cannot rule out the chance for isold tstms
across the FA during the afternoon, shifting to the coast
through the early evening. Our FA is not currently outlooked by
SPC for any severe threat on Saturday.
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
Cold front slips off the coast Sat evening...w/ drying/gusty
WNW winds and temperatures returning to near normal (beginning
Sun). Sfc hi pres drifts over the FA Sun night...resulting in
mainly SKC and chilly conditions. Quick moving low pressure
tracks from the OH Valley Mon across the FA Mon night w/
increasing cloudiness and low PoPs (15-25%). Another warm up
begins Tue and continues through Wed as sfc hi pres sets up off
the coast...and return S flow develops. Dry and mild Tue...a
warm front lifting through the FA Tue night may clip the region
w/ clouds and low PoPs (10-20%). Breezy/warm Wed ahead of
approaching cold front from the W. Models push that front
through the region late Wed (possibly accompanied by SCT RASH).
Lows Sat night in the u30s NW to the l40s SE. Highs Sun in the
m-u50s. Lows Sun night from the l30s N and W to the u30s-around
40F SE. Highs Mon in the u50s-around 60F on the eastern shore
to the 60s elsewhere. Lows Mon night in the u30s NW to the m40s
SE. Highs Tue again in the u50s-around 60F on the eastern shore
to the 60s elsewhere. Highs Wed in the 60s on the eastern shore
to the 70s elsewhere.
&&
.AVIATION /03Z THURSDAY THROUGH MONDAY/...
Weak high pressure ridge will extend from the Atlantic westward into
Virginia and North Carolina through Friday. Low pressure will
organize over the Central Great Plains Friday and will move
northeast into the Great Lakes Saturday. A strong cold front will
cross the region late Saturday and Saturday evening. High pressure
builds over the Mid Atlantic States Sunday.
As of 00z...An area of light rain was dissipating over southeast
Virginia. Mainly VFR conditions were present at the TAF sites. MVFR
visibilities are expected overnight at RIC and SBY. Models were in
opposition as to how low conditions will go Thursday morning.
Considering cloud cover...expect visibilities to go no lower than 1
to 2 miles and that will be mainly in the Piedmont Region. NAM12
soundings do not support widespread IFR ceilings. Conditions improve
by around 14-15Z. Winds will be mainly from the south at around 5 to
10 knots.
OUTLOOK...Dry weather is expected through Friday. Showers and
thunderstorms are expected with the cold front late Saturday and
Saturday evneing. Dry weather returns Sunday. There will be a small
chance for showers on Monday as a weak cold front moves through.
&&
.MARINE...
No headlines into the weekend. Predominantly SSE winds aob 15 kt
through Fri night. Waters ranging from 1-2 ft waves over the
Ches Bay and 2-3 ft seas over cstl wtrs. With lo pres invof FL
Thu pushing off the southeast coast Fri...guidance indicating
some increasing long period swell moving up to the local area
wtrs for Fri-Sat w/ seas building to 4-6 ft...which would lead
to SCA headlines along the coast starting around Fri night. Some
increase in SSW winds resulting from WAA Sat...though speeds
expected to remain below SCA. Cold front crosses the waters Sat
night...to be followed by a period of modest low level CAA. SCAs
likely Sat night through Sun morning before winds wane to end
of the weekend.
&&
.CLIMATE...
Feb 2017 is shaping up to rank among the warmest on record
given continued warmth over the next week. Daily record highs
are listed below for Thu-Sat, with the top 3 warmest
February`s on record listed below that. Expecting RIC, ORF, ECG
to be at least into the top 3 warmest (and possibly the
warmest). SBY looks on track to be 4th or 5th warmest.
Daily Record Highs for Thursday 2/23, Friday 2/24 and Saturday 2/25:
2/23 2/24 2/25
RIC 75 in 1985 82 in 1985 83 in 1930
ORF 79 in 1975 82 in 2012 81 in 1930
SBY 74 in 1943 77 in 2012 80 in 1930
ECG 77 in 1975 79 in 1985 77 in 1985
Warmest February`s on record:
* RIC:
1) 49.9 (1890)
2) 48.5 (1976)
3) 48.1 (1884)
* ORF:
1) 52.4 (1890)
2) 50.5 (1909)
3) 50.1 (1990)
* SBY:
1) 46.1 (1976)
2) 45.8 (1984)
3) 45.7 (1925)
* ECG:
1) 52.1 (1990)
2) 51.8 (1939)
3) 50.3 (1976)
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...None.
NC...None.
VA...None.
MARINE...None.
&&
$$
SYNOPSIS...JDM
NEAR TERM...JDM/SAM
SHORT TERM...JDM
LONG TERM...ALB
AVIATION...LSA
MARINE...ALB
CLIMATE...
Area Forecast Discussion
National Weather Service Burlington VT
748 PM EST Wed Feb 22 2017
.SYNOPSIS...
Expect above normal temperatures...on the order of 15 to 25
degrees warmer...to continue right through Saturday. Saturday
will be the warmest day with highs in the 50s to around 60 and
these temperatures could set new record highs. The above normal
temperatures will lead to increased snowmelt and runoff and
increase the potential for ice jams and river flooding.
Widespread rain later Saturday into Saturday night could further
enhance the potential for flooding across parts of the North
Country.
&&
.NEAR TERM /UNTIL 7 AM THURSDAY MORNING/...
As of 611 PM EST Wednesday... The diurnal cumulus clouds have
started to dissipate based on latest obs and satellite imagery
so I lowered our sky cover forecast for the next couple of hours
but there upstream obs do show that some low and mid level
clouds will build back into the region overnight so the updates
were largely cosmetic. Upstream locations are also seeing some
fog and low stratus resulting from the warm air over a moist
snow pack. With the melting that occurred already and temps not
likely to drop below freezing the idea of patchy fog looks like
it should play out well. Lows will generally be in the mid 30s
to mid 40s. Any precipitation overnight will be rather spotty
and generally confined to parts of northern New York.
&&
.SHORT TERM /7 AM THURSDAY MORNING THROUGH FRIDAY NIGHT/...
As of 326 PM EST Wednesday...Forecast remains on track for
above normal temperatures...both daytime and nighttime
temperatures. This will lead to ice breakup in the
rivers...especially northeast New York and areas along and north
of Route 2 in Vermont where river ice still prevails. High
temperatures on Thursday will be in the upper 40s to upper
50s...but mid 40s to lower 50s on Friday. Either way both days
are still above normal. Upper trough passing north of the area
will keep main forcing north of the border...but we could still
see some light rain showers. Looking at rainfall amounts less
than a tenth of an inch on Thursday. Warm front will be to our
southwest on Friday and will eventually push up into the region
late Friday into Friday and lift north of the border by early
Saturday. Could be some showers with this front...but again not
a lot of precipitation...generally less than two tenths of an
inch. These temperatures should still promote snowmelt/runoff
and we should begin to see 1 to 3 foot rises on rivers late
Thursday into Thursday night...but most of the mainstem rivers
are starting off low and should be able to handle the increase.
Further rises are expected on Friday...but the greatest concern
will come on Saturday when even warmer temperatures and
widespread rain eventually moves in.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
As of 326 PM EST Wednesday...On Saturday we will be in the warm
sector ahead of approaching cold front. Strong southwesterly
return flow will be in place as low pressure system moves from
the Great Lakes region north of our CWA later Saturday and
Saturday night. 850 temps will reach about 10 C on Saturday, max
temps will be in the mid 50s to around 60. Strong cold front
pushes west to east across our forecast area Saturday night.
Have high pops mentioned from 18z Saturday through 06z Sunday.
Moderate rain is expected area wide. Storm total QPF will range
from about half an inch to around an inch. See hydrology section
for ice jam concerns. Strong cold air advection behind cold
front will keep temperatures on Sunday closer to seasonal
normals, mainly 30s across the area. Sunday afternoon through
Monday afternoon will feature quieter and more seasonable
weather with a ridge of surface high pressure briefly over the
area. By Monday evening a weaker low pressure system will pass
to our south and bring just a chance for some rain and snow
showers. Towards the middle of the week temperatures will warm
back above seasonal normals and a quieter weather pattern
develops. Both GFS and ECMWF indicate a large scale system for
the second half of the work week to impact the north country,
looks very similar to Saturday`s system with rain and then snow.
&&
.AVIATION /01Z Thursday THROUGH Monday/...
Through 00Z Friday...Mainly VFR conditions expected through the
period. Satellite loop showing some low clouds moving east
across northern New York at this time. Expecting ceilings to
lower overnight, as suggested by forecast Bufkit soundings. RAP
model sugeesting mainly low clouds over the region overnight and
not much in the way of fog. Thus, have opted to go more with a
lower cloud deck than fog overnight at the TAF sites. Guidance
hinting at some southerly surface wind gusts at or above 20
knots during the day on Thursday, so have some developing
between 13Z to 15Z on Thursday.
Outlook 00Z Friday through Monday... Additional fog/BR possible
Thursday Night into Friday...as weak backdoor front results in
a wind shift to the north. Very gusty southerly winds
develop...along with a line of showers with embedded heavier
rainfall for Sat. Localized areas of turbulence and shear
likely...along with MVFR conditions in the heavier showers. Rain
transitions to mountain snow showers with lingering IFR vis
possible at SLK/MPV Sat night into Sunday. MVFR possible again
on Monday with more showers in the area.
&&
.HYDROLOGY...
As of 326 PM EST Wednesday...Temperatures Thursday through
Saturday will be 15 to 25 degrees above normal...both during the
day and into the night. This will continue to support the
breakup of river ice and increase the potential for ice jams.
Rivers with ice still in them are mainly over northeast New York
and the northern third of Vermont...generally north of Route 2.
We will see some light showers Thursday and Friday...but
amounts should not have much of an impact. The above normal
temperatures will contribute to snowmelt/runoff and we should
see noticeable rises Thursday and Friday...1 to 3 foot rises on
Thursday...but rivers are starting off low and should be able to
handle these initial rises. Main concern will likely be on
Saturday and into Saturday night when record/near record high
temperatures further increase snowmelt/runoff and widespread
rain moves in with at least a half to one inch of rain expected.
Sharp rises will likely occur during this period and greatest
ice jam/river flooding potential should be during this time
period.
&&
.BTV WATCHES/WARNINGS/ADVISORIES...
VT...None.
NY...None.
&&
$$
SYNOPSIS...Evenson
NEAR TERM...Evenson/Deal
SHORT TERM...Evenson
LONG TERM...Neiles
AVIATION...WGH/Neiles
HYDROLOGY...Evenson
Area Forecast Discussion...Updated
National Weather Service Billings MT
826 PM MST Wed Feb 22 2017
.UPDATE...
Current radar imagery shows snow beginning to decrease north
of Billings with activity looking less convective across the
region with diurnal cooling. NAM and HRRR showing less snow in the
overnight period for Yellowstone and Musselshell counties but
small convective elements are still capable of producing a quick
couple tenths of an inch of snow but snow is melting as it falls
most lower elevations. However...higher locations closer to 4000
foot elevation are seeing snow stick a bit better reflected by
reports of a couple of inches in Molt and Big Timber. Minor
updates to forecast to add more fog but suspect any additional
accumulation after midnight will be light in Billings. borsum
&&
.SHORT TERM...valid for Thu and Fri...
Increased snow accumulations with next system due to a more
northerly track. Storm system will impact the area with periods
of snow over the next 72 hours, heaviest along and west of a
Roundup to Broadus line and specifically in the north and east
facing foothills. Issued Winter Storm Warnings for western
mountains and favored foothills locations, with Winter Weather
Advisories for surrounding areas. At this point SE MT looks to see
only a couple of inches of snow so left those areas out of
highlites for now but if system trends any further north will need
something for at least Powder River and Carter counties.
Broad west coast trof coming together this afternoon as energy
drops south from western Canada and fuses with energy out of
California. Plenty of energy and moisture out ahead of the upper
low which is producing rain/snow showers across much of the
forecast area this afternoon. Have picked up nearly a tenth of an
inch precipitation in the Billings area so far today from this
activity. Surface cold front is slowly moving through western
zones heading into the foothills this afternoon, after clearing
the eastern portion of the forecast area this morning. Additional
colder air will filter in tonight as the cold front builds into
the foothills and deepens up. This will transition precipitation
from convective in nature to more stratiform overnight, with
precipitation turning over to all snow late evening. Jet energy
will develop over the area early tomorrow morning and persist
through the day Thursday providing the dynamics for the heaviest
snowfall to develop. Core of upper system will slide across
Southern/Central Wyoming Thursday afternoon into the overnight
hours providing additional snow enhancement over southern zones.
Low moves into the Dakotas on Friday which should taper snow rates
down and bring an end to significant impacts so ended highlites
mid day Friday.
Temperatures never get terribly cold with this system with highs
Thursday and Friday in the 25 to 35 degree range and lows in the
15 to 25 range. This sets up a scenario where a good amount of
melting is possible during the daylight hours so accumulations in
some areas may be overdone a bit. Lowered snow ratios a good deal
during the afternoon hours. Metro model simulations show afternoon
road temperatures in the lower elevations pushing into the 40s so
roads that get snow covered and slick during the night may melt
out during the day or become generally slushy. Foothill and
mountain roads will be snow packed.
Snow amounts...Latest model and WPC consensus shows western
mountains in the 10 to 16 inch range, Bighorn mountains in the 8
to 12 inch range. The Beartooth/Red Lodge foothills can expect 6
to 12 inches with 5 to 10 in the Sheridan foothills. Central zones
will see 3 to 6 inches trending toward 6 to 10 inches further
west into the Big Timber and Livingston areas. This snow is going
to be more of the wet variety so folks will need to take it easy
shoveling, though melting on concrete/asphalt surfaces during the
day will help. Chambers
.LONG TERM...valid for Sat...Sun...Mon...Tue...Wed...
Little in the way of changes for the extended forecast period.
Overall, expect a progressive and unsettled pattern, with below
normal temperatures through the period.
Weak energy will cross the region Saturday, with continued
showers expected. A stronger wave crosses the area Saturday
night/Sunday morning, and should spread more widespread showers
across the region. The system is pretty quick...so do not expect
significant snow accumulations at this time. Shortwave ridging
will build over the region by Sunday afternoon. A Pacific trof
pushes into the pacific northwest by Sunday night and digs south,
flattening the flow across the CWA. Trof remains open and pushes
east through Tuesday. Models vary greatly on how they handle the
system crossing the region, but generally appear to bring pieces
of energy and pacific moisture through the region through Tuesday
night. Expect to see some brief clearing for Wednesday as flow
aloft turns northwest behind the trof, before the next system
approaches Thursday. AAG
&&
.AVIATION...
Snow showers and patchy fog continue to produce MVFR down to VLIFR
CIGS and VSBYS across western and central portions of the area
including KBIL and KSHR this evening. Snow is expected to become
more widespread late tonight through Friday, with IFR to LIFR
CIGS and VIS possible in heavier snow throughout the period.
Mountains will continue to see obscurations. AAG/STP
&&
.PRELIMINARY POINT TEMP/POPS...
Thu Fri Sat Sun Mon Tue Wed
-----------------------------------------------------------
BIL 027/033 021/033 016/032 015/033 015/033 018/031 020/038
68/S 65/S 32/J 21/B 22/J 32/J 22/J
LVM 020/029 013/028 011/027 009/029 012/032 014/031 017/034
98/S 76/S 42/J 21/N 33/J 32/J 22/J
HDN 025/036 019/035 015/033 014/034 013/033 016/032 017/039
68/S 64/S 22/J 21/B 12/J 33/J 12/J
MLS 027/038 022/036 019/035 020/036 018/035 020/033 020/040
33/S 22/S 22/J 21/B 22/J 33/J 11/N
4BQ 025/037 019/035 016/035 018/035 015/037 020/033 017/038
46/S 43/S 12/J 21/B 01/B 34/J 11/N
BHK 023/033 018/032 016/031 017/033 015/034 017/029 016/035
32/S 21/E 22/J 21/B 11/B 34/J 11/B
SHR 023/031 014/029 009/030 008/029 008/031 012/030 014/035
69/S 75/S 31/E 11/B 12/J 34/J 22/J
&&
.BYZ WATCHES/WARNINGS/ADVISORIES...
MT...Winter Weather Advisory in effect from midnight tonight to
noon MST Friday FOR ZONES 28-29-34-35-39-40-42-57-58-63-64.
Winter Storm Warning in effect from midnight tonight to noon
MST Friday FOR ZONES 38-41-56-65>68.
WY...Winter Weather Advisory in effect from midnight tonight to
noon MST Friday FOR ZONE 98.
Winter Storm Warning in effect from midnight tonight to noon
MST Friday FOR ZONE 99.
&&
$$
weather.gov/billings
Area Forecast Discussion
National Weather Service Grand Rapids MI
1001 PM EST Wed Feb 22 2017
LATEST UPDATE...
Update
.SYNOPSIS...
Issued at 329 PM EST Wed Feb 22 2017
Mild weather will continue with highs in the 50s both Thursday and
Friday, and lows mainly 40 to 45. However rain showers will arrive
Thursday night and linger through Friday night. Some thunderstorms
will also be possible, with some of these storms possibly severe
into Friday evening.
Colder air moves in late Friday night into Saturday, and the rain
will be switching over to snow. Some light snow accumulation is
possible Saturday. Another chance of rain and snow moves back in by
Tuesday night and Wednesday. Cooler for the weekend and into early
next week with highs mainly be 35 to 40.
&&
.UPDATE...
Issued at 1002 PM EST Wed Feb 22 2017
The area of showers has exited our CWA to I lowered pops to 20 pct
for the next few hours and below 5 percent by morning. The HRRR
and RAP model continue to forecast fog following the cold front. I
am still on the fence with this since there is cold air behind
this cold front and typically we don`t get for in that set up.
Still both models did great on the fog last night so I do have
some fog after midnight in the grids.
UPDATE Issued at 743 PM EST Wed Feb 22 2017
I increased the chance for measurable rain to around 40 pct over
our NW and N CWA this evening into tonight. The latest radar image
loops shows showers north of Hart moving east northeast. There is
a strong low level jet feeding these showers, if there were a
little more moisture in the 850 mb to 700 mb layer than there
actually is we would have much larger coverage and maybe even a
few thunderstorms. I continue to believe the dry air in that layer
will prevent the showers from becoming more widespread this
evening.
&&
.SHORT TERM...(This evening through Friday night)
Issued at 329 PM EST Wed Feb 22 2017
A few light showers will be possible tonight with a cold front
passing through. It won`t be as warm Thursday behind this front,
but it will still be in the 50s. Then a wet and stormy system
arrives for Thursday night through Friday night.
The moisture does not look that impressive with tonight`s front and
most areas probably stay dry. but will carry low POPs along and
north of I-96. A northerly wind moves in for Thursday, keeping us
slightly cooler. Mid 40s for Central Lower to around 60 for South
Central Lower. After a cloudy start on Thursday we should see some
sun into the afternoon, but no pcpn is expected.
Main story will be the system approaching and moving through
Thursday night through Friday night. Still appears to be potential
for severe storms, with the evening looking most favorable. We see
a coupled jet move in by late afternoon, with a low level jet
arriving into the evening. CAPE values are only modest, but with
the amount of dynamics believe we will see storms. It seems like
the highest potential for severe storms will be along and south of I-
96 where dew points will manage to reach the 50s as this area gets
into the warm sector. However it may be somewhat questionable,
whether the best dynamics reach us during the highest instability.
If the LLJ is delayed too much, much of the action could be to our
south. If we see severe storms, damaging winds will be the main
hazard.
It will be a wet system with rain totals expected to be around an
inch. Perhaps higher in West Central Lower. At the onset of the
pcpn Thursday night we may see a bit of rain/snow mix over Central
Lower, but this should be brief and not cause issues.
Later in the event, the colder air arrives in the west just prior to
daybreak Saturday, so have included the chance of snow mixing in
late Friday night there.
.LONG TERM...(Saturday through Wednesday)
Issued at 329 PM EST Wed Feb 22 2017
The long term period will start off with the low pressure system
pulling away from the region on Saturday. After being dry
slotted...the wrap around moisture will pivot through the CWA during
the day and into the evening. Thus...higher POPs are warranted.
Based on the thickness values this looks to be a mainly snow
event...but some rain could mix in especially early on. Surface
temperatures will largely be above freezing...so impacts will likely
be limited. It appears later Saturday...as the temperature starts
to drop off below freezing...that the risk for impacts will be
elevated. This is also when the precipitation will be winding down.
Sunday into Monday the risk for precipitation looks low. One storm
tracks up the OH valley for Monday. Overall the trend of this track
has been further south...so this system should miss our region. Then
on Tuesday another storm will be approaching from the west. Will
feature increasing POPs for Tuesday. This system has trended
warmer...so it is currently looking like a rain event.
&&
.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
Issued at 700 PM EST Wed Feb 22 2017
There are two issues tonight to consider. First is the threat for
fog again tonight and second is the chance of showers and
thunderstorms. There is still some fog along the lake shore from
Grand Haven north and with the front coming through shifting winds
to the west it may well come on shore. However I would think since
this is a cold front and there is 40 knots as close to the ground
as 500 ft in the 06z to 09z time frame there would be way to much
wind to get dense fog. None the less the RAP and HRRR show this
impacting MKG and those models did very nicely last night so I did
put dense for in the MKG TAF after the winds let up (09z-14).
Those same models show the fog reaching GRR toward sunrise. Once
again this is behind the front (cold front) but winds do let up
toward morning so I did put a few hours of dense fog there too but
I am not 100% on this happening. Elsewhere I should expect the
mixing behind the cold front to keep fog becoming to dense but I
do believe we will be seeing a period of low clouds till mid
morning then skies should clear.
As for convection...there is 40kt to 50kt low level jet that puts
southwest Michigan to it`s left, which is a great place to get
storms to happen. There is 300 to 500 j/kg of most unstable cape
too but the instability is elevated above 700 mb. Also there is a
considerable amount of dry air once one gets above the 850 mb. So
I put VCSH in all the TAFs in the 03z to 06z time frame to cover
this.
&&
.MARINE...
Issued at 455 PM EST Wed Feb 22 2017
Webcams show vsbys have improved at Holland, Grand Haven and
Ludington over the last couple hours, but vsbys where still very
low at the Muskegon waterfront. The trend will continue to be
improving vsbys as winds increase, so will allow the fog advisory
to expire at 5 PM.
&&
.HYDROLOGY...
Issued at 1201 PM EST Wed Feb 22 2017
Snowmelt in the headwaters of the Muskegon River basin has caused
the river to rise to above normal for late February. The Grand and
Kalamazoo rivers are running near normal. Showers and storms on
Friday may put down swaths of rainfall in excess of a half or
perhaps 1 inch. Some rivers would be susceptible to rising above
bankfull if that amount of rain falls in their respective basins.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...None.
LM...Small Craft Advisory until 4 AM EST Thursday for LMZ845>849.
&&
$$
UPDATE...WDM
SYNOPSIS...JK
SHORT TERM...JK
LONG TERM...MJS
AVIATION...WDM
HYDROLOGY...CAS
MARINE...JK
Area Forecast Discussion...UPDATED
National Weather Service Gray ME
917 PM EST Wed Feb 22 2017
.SYNOPSIS...
Low pressure moving east through southern Canada will allow a
mild southwesterly flow to continue tonight through Thursday.
Highs will climb into the 50s to near 60 across New
Hampshire...with 40s to lower 50s over western Maine. A weak
cold front will try and push south across the area Thursday
night with a few rain showers before returning north as a warm
front by late Friday. A strong cold front and more widespread
showers will move across the region Saturday night followed by
a drier and colder air mass for Sunday.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
915 PM Update: Have continued to lower temperatures for most
locations based on evening trends that show a few sites /RKD-
SFM-BML/ already in the upper 20s. No signs of fog at this
juncture...but HRRR is now starting to pick up on coastal
stratus potential so will maintain previous forecast changes.
Finally...issued a SPS earlier based on re-freezing of water on
roads due to the quickly falling evening temperatures.
716 PM Update: Following rapid 1-2 hour temperature drops as
winds decouple this evening. Overnight lows were tweaked
downward as a result. Otherwise...primary changes to the
forecast are to adjust fog/low cloud wording overnight with some
patchy fog pretty much possible anywhere while NARRE-TL and
HRRR/RAP BUFKIT profiles along with statistical guidance signal
some coastal stratus potential after midnight. Moved the
forecast in this direction...and will monitor late evening
trends before making further adjustments.
513 PM Update: Minor changes to match late afternoon
temperatures and reduce cloud cover based on the last few
visible images of the late afternoon.
Previous discussion below...
The evening will start out mostly clear as per satellite
imagery. By later tonight patchy valley fog is expected to
develop due to the residual low level moisture from the snowmelt
this afternoon combined with calm winds. Tonight`s overnight
lows will be mild with temperatures in the upper 20s to lower
30s.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH THURSDAY NIGHT/...
Thursday models show a mild southwest flow to develop with h85
temps aloft to reach +6 to +8C. This flow should allow temps to
reach near 50 in the mountains and southern Maine and could
reach near 60 over southern NH. A weak cold front tries to push
south across the area but weakens and then washes out as it
moves through the area by Thu evening. A few showers are
possible in the mountains with its passage Thursday afternoon
and evening but it should remain dry elsewhere. Patchy fog may
once again form overnight due to the snowmelt. Temps will once
again be mild with overnight lows ranging from near 30 in the
mountains and mid 30s to lower 40s elsewhere.
&&
.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
Models are in fairly good agreement in the long term. A frontal
boundary will stall just south of the region Friday...then start
to push back through the area as a warm front Friday night as
low pressure moves northeast through southern Quebec. This will
lead to a rather warm day Saturday. As the low continues
northeast Saturday night the trailing cold front will cross the
region with rain showers which will change to snow showers in
the mountains overnight Saturday night as colder air pushes
into the region. At this time it appears that the moist system
moving northeast in Atlantic will not phase with the northern
frontal system until after it passes through the region. The
models continue to show the heaviest showers with the frontal
passage in the mountains...and combined with the snowmelt caused
by the warm temperatures may produce some ice movement on the
rivers.
Drier air moves into the area Sunday but with a northwest flow
there will be a persistent threat of snow showers in the
mountains through Monday. Weak systems pass north and south of
the region late Monday and Tuesday with the next threat of
significant precipitation for the area on Wednesday.
&&
.AVIATION /02Z THURSDAY THROUGH MONDAY/...
Short Term...
Summary: Southwesterly flow continues through Thursday as low
pressure passes north of the region with a few showers arriving as
an attendant cold front pushes through the area Thursday night.
High pressure then noses into the region from the north on Friday
before stalled frontal boundary to our south returns north as a warm
front.
Restrictions: VFR attm and this will continue through the evening.
Lots of ground moisture out there from recent melting and there are
some signs given good radiational cooling that this will result in
some fog development...particularly with continued good moisture
advection in the southwest flow aloft. NARRE-TL points to low
ceiling potential over southern NH/coastal ME as well...with good
agreement from the LAV/MAV/MET. Thus...expect IFR fog and some
coastal low stratus to develop after midnight with conditions a bit
better /MVFR/ at HIE/LEB.
For the day on Thursday...expect gradual improvement to VFR outside
of LEB/HIE where nearby approaching front will help MVFR cloudiness
linger longer...potentially through the day. MVFR restrictions
possible in a few light rain showers Thursday night before a return
to VFR conditions on Friday morning. Front to our south returns
north Friday afternoon...with restrictions in rain showers again
possible towards evening.
Winds: Calm/light-variable winds overnight will become southwest
5 to 10kts for the day on Thursday before diminishing to 5kts or
less Thursday night and shifting northwest overnight. Light
northwesterly winds /less than 10kts/ expected Friday.
LLWS: LLWS possible Thursday evening in southwesterly flow ahead of
approaching surface cold front. Frontal passage will end the threat
from north to south overnight.
Long Term...MVFR to IFR conditions possible in showers and fog
Friday night into Saturday night. MVFR to IFR conditions
will persist in the mountains in scattered snow showers through
Monday.
&&
.MARINE...
Short Term...A warm front moves north across the waters tonight.
A developing southwest flow Thu will begin to build seas to
near 5 ft by evening and continue Thu night. SCA`s may be
needed for Thu night due to seas over the outer waters.
Long Term...SCAs likely outer waters late Saturday through
Monday and again on Wednesday.
&&
.GYX WATCHES/WARNINGS/ADVISORIES...
ME...None.
NH...None.
MARINE...None.
&&
$$
SYNOPSIS...
NEAR TERM...Arnott/Marine
SHORT TERM...Marine
LONG TERM...Jensenius
AVIATION...Arnott
MARINE...
Area Forecast Discussion
National Weather Service Melbourne FL
933 PM EST Wed Feb 22 2017
.UPDATE...
...Locally Heavy Rain Across Volusia County Overnight...
Mid level closed low will slide southeast toward the srn FL
peninsula overnight and allow surface low pressure to organize off
the FL east coast into Thursday morning. Deep layer lift will
transition offshore and across nrn areas overnight as low level
onshore flow increases north of Cape Canaveral after midnight. This
will allow high rain chances to continue for the nrn forecast area
through the overnight hours with just a chance of showers across srn
sections as low level flow becomes offshore and mid levels dry
across the srn peninsula. Have made adjustments to lower rain
chances srn areas and kept high rain chances north. Kept a slight
chance for thunder across nrn areas as well with lift from the mid
level low and stronger low level convergence north of the developing
low pressure area. Local heavy rain threat will continue for mainly
nrn Brevard and Volusia counties where showers will stream onshore
from the Atlantic. Lows will range from the mid to upper 50s srn
areas and warmest in the mid 60s along the Volusia coast where
breezy to windy onshore flow will continue along the beaches and the
immediate coast.
&&
.AVIATION...
Light to moderate rain with showers expected to continue for nrn
terminals overnight with heaviest showers moving onshore from the
Atlc from KOMN-KTIX. Mainly MVFR CIGS KFPR northward with brief IFR
VSBYs with +SHRA KDAB vcnty. Have TEMPO conds for lower CIGs 09z-13z
for terminals mainly north of KISM-KTIX. Higher rain chances will
occur north of a KISM-KTIX line on THU with scattered clouds KFPR
southward on Thu.
&&
.MARINE...
NAM and HRRR models are the most aggressive with tight pressure
gradient affecting nrn waters into THU morning north of a developing
low pressure area across the east central FL Atlc waters. GFS
indicates weaker winds with tighter pressure gradient mainly north
of Ormond Beach. Will keep all Advisories and Gale Watch in place
which may need to be upgraded to a Gale Warning across the nrn
waters for the next forecast package. Developing weaker offshore
flow south of the low pressure area will bring improving conditions
into Thursday south of Sebastian Inlet. Winds and Seas will remain
hazardous north of Cape Canaveral into Thursday and Thu night.
&&
.CLIMATE...
Melbourne Airport recorded 2.50 inches of rain through 9 pm this
evening. This sets a new record rainfall for todays date. The
previous record was .75 in 1964.
&&
.PRELIMINARY POINT TEMPS/POPS...
DAB 64 75 66 80 / 100 60 20 10
MCO 60 77 64 83 / 80 40 10 10
MLB 59 76 67 80 / 80 60 20 10
VRB 58 77 66 81 / 70 40 20 10
LEE 61 77 62 82 / 80 40 10 0
SFB 60 77 64 81 / 90 50 20 10
ORL 60 77 65 82 / 80 40 10 10
FPR 58 77 64 81 / 70 40 20 10
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...None.
AM...Gale Watch from 4 AM EST Thursday through Thursday afternoon for
Flagler Beach to Volusia-Brevard County Line 0-20 nm-
Flagler Beach to Volusia-Brevard County Line 20-60 nm.
Small Craft Advisory until 4 AM EST Thursday for Flagler Beach
to Volusia-Brevard County Line 0-20 nm-Flagler Beach to
Volusia-Brevard County Line 20-60 nm-Sebastian Inlet to
Jupiter Inlet 0-20 nm-Sebastian Inlet to Jupiter Inlet 20-
60 nm.
Small Craft Advisory from 1 PM Thursday to 4 AM EST Friday for
Flagler Beach to Volusia-Brevard County Line 0-20 nm-
Flagler Beach to Volusia-Brevard County Line 20-60 nm.
Small Craft Advisory until 4 AM EST Friday for Volusia-Brevard
County Line to Sebastian Inlet 0-20 nm-Volusia-Brevard
County Line to Sebastian Inlet 20-60 nm.
&&
$$
Volkmer/Ulrich
Area Forecast Discussion
National Weather Service Omaha/Valley NE
541 PM CST Wed Feb 22 2017
.SHORT TERM...(tonight through Saturday)
Issued at 241 PM CST Wed Feb 22 2017
...Winter storm with near blizzard conditions will affect part of
the forecast area Thursday night through Friday night...
The calm before the storm today, with another record record
breaking day at both Lincoln and Omaha with highs in the mid 70s!
This will be in stark contrast to the expected wintry weather that
develops by the end of the work week.
Upper low across western US with 60-80 meter height falls and a
100-120 knot 300mb jet will close off tonight and then cross the
Rockies Thursday then eject onto the Plains Thursday night and
Friday.
Dry weather expected tonight with northerly flow behind a cool
front that has moved through the area. Surface cyclogenesis
develops across the western High Plains Thursday then moves east
northeast in a favored trace to bring heavy snow to the much of
the central and northern Plains, and even a thunder threat in
southeast NE and southwest IA within a dry slot.
Early Thursday morning should be dry, but a rain/snow mix will be
spreading eastward along the SD border area into northeast NE
through the day. Meanwhile, thunderstorms may develop along south
of I80 through mid afternoon Thursday into Thursday evening,
although the 12z High-res ARW/NMM models and now most the 18z ESRL
HRRR suggest these storms could even be south of the forecast
area in northeast KS and northwest MO.
Substantial wintry weather develops by Thursday evening in
northeast NE, with rain and a chance for thunder for east
central, southeast NE, and western Iowa. Isentropic lift on the
295K surface suggests 3 to 6 g/kg of moisture feeding into
northeast NE, which would suggest at least 6 to 12 inches of storm
total snow possible in that area. The rain/snow line may not even
make it to the I80 corridor until early Friday morning, but then
spreading across the remainder of the forecast area during the
morning.
There is some concern of the exact track of this storm, with
various models showing slightly different paths. The Nam was
generally discounted for being too far north, although the 18z
Nam began trending a little further south. Generally used a
consensus of other available models.
There is also a high degree of concern that because of the strong
wind gusts at or above 35 mph by late Thursday night into Friday,
we could be potentially be near or at blizzard criteria in
northeast NE. For this reason, the existing winter storm watch was
converted to a blizzard watch for portions of SD and northern IA.
Regarding headlines in our area, we have decided to upgrade the
existing winter storm watch currently in effect to a winter storm
warning, which begins at 6 pm Thursday. This includes the area
Albion to Norfolk to Wayne and areas northwest, given confidence
of heavier snow and potential near blizzard conditions that will
eventually develop in that area. Have opted to issue winter storm
watches southeast of this area, which includes Columbus to
Fremont to Blair to Denison, with a staggered start time from 10
pm Thursday to 6 am Friday. In this area, we have upped the
snowfall to the 4-7" range, but this area will also experience
near blizzard conditions on Friday, thus the reasoning for the
watch. Farther south, along I80, we have just 1-2" forecast, and
just barely a dusting near the NE/KS/MO border area.
Impacts from this storm will eventually be high, with a significant
impact to travel expected Thursday night into Friday night, due
to the combination of heavy snow, high winds, blowing snow, and
eventually near blizzard conditions in some areas. We have also
extended headlines to linger into Friday evening as impacts will
still be ongoing as the storm system slowly pulls away.
Saturday should be dry with high pressure across the forecast area.
.LONG TERM...(Saturday night through Wednesday)
Issued at 241 PM CST Wed Feb 22 2017
Didn`t have a lot of time to spend on the extended portion of the
forecast. There is another quick moving front that could bring a
slight chance of rain/snow to parts of the area Sunday. Another
weather system could bring rain/snow Monday night into Tuesday and
then dry for Wednesday.
&&
.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
Issued at 527 PM CST Wed Feb 22 2017
VFR conditions are expected for the first 12-18 hours with
conditions deteriorating late in the TAF period as a storm system
moves into the Plains. Precipitation will be moving in late in the
period as well, but should be mainly rain through 00Z Fri.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...Winter Storm Watch from Friday morning through Friday evening
for NEZ034-044-045.
Winter Storm Watch from Thursday evening through Friday evening
for NEZ015-032-033-042-043.
Winter Storm Warning from 6 PM Thursday to midnight CST Friday
night for NEZ011-012-016>018-030-031.
IA...Winter Storm Watch from Friday morning through Friday evening
for IAZ043-055.
&&
$$
SHORT TERM...DeWald
LONG TERM...DeWald
AVIATION...Kern
Area Forecast Discussion
National Weather Service New York NY
953 PM EST Wed Feb 22 2017
.SYNOPSIS...
High pressure over the western Atlantic will influence the weather
across the Tri-State through Thursday. A mild, damp, spring-like
pattern Friday and Saturday will give way to a more seasonal
pattern for the beginning of next week.
&&
.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
Main concern for tonight continues to be the development of fog
and low clouds. A light southerly flow over the area tonight
will gradually increase low level moisture. Cooling surface
temperatures in combination with weak warm advection above the
surface will create a steepening temperature inversion. Moisture
will become trapped beneath this inversion overnight into the
early morning hours. Areas of fog and low stratus will likely
result from these conditions. Fog has already started as of 02z
for a few spots over eastern Long Island. with low stratus being
more widespread. Have noted this signal in BUFKIT profiles from
the HRRR, RAP and NAM-4km, but the bulk of fog development may
not occur until after midnight. The fog and low stratus should
then expand northward towards into the early morning hours. How
low widespread visibilities ultimately get is uncertain at this
time, but widespread dense fog is a possibility, mainly near the
coast and especially over Long Island. Have issued an SPS for
Suffolk County to address dense fog being at least patchy.
Low temperatures will be in the upper 30s inland and low to mid 40s
along the coast.
&&
.SHORT TERM /6 AM THURSDAY MORNING THROUGH THURSDAY NIGHT/...
High pressure will remain across the western Atlantic, pumping a
warm and moist southerly flow around it towards the local area.
Aloft, a split flow pattern continues with core of northern stream
well to our north and a slow moving upper low across the southeast
states within the southern stream.
Areas of fog and low stratus start the day on Thursday. The first
forecast challenge is the duration. The fog should lift through the
morning hours, but the stratus could hang on into the early
afternoon. This creates another challenge with regards to
temperatures. There is high confidence in seeing unseasonably warm
temperatures for this time of year. However, how quickly clearing
occurs will be important to how warm it gets away from the coast.
Highs should be able to reach the middle and upper 60s north and
west of the city where clearing occurs the quickest. In the NYC
metro, readings will be in the lower to middle 60s. Further east
across southern Connecticut and Long Island, temperatures will be
held in the 50s to near 60 due to onshore flow. If the clouds clear
quicker, then highs could end up warmer and some records could be
broken. If clouds hang on longer, then highs could be held down
several degrees from current forecast.
For Thursday night, a weak boundary tries to move into the area from
the north. The boundary likely stalls nearby overnight and acts as a
focus for some areas of drizzle and fog development in a continued
moist environment. There is also the chance of some rain along this
boundary. Lows continue mild in the 40s to near 50 degrees.
&&
.LONG TERM /FRIDAY THROUGH WEDNESDAY/...
Not much change to the forecast for Friday through Sunday. The
operational models are catching up with the conceptual model of
light rain and drizzle Friday night into Saturday. The timing of the
cold frontal passage has been narrowed down to the first part of
Saturday night, with the GFS now latching onto the ECMWF timing.
The models are showing some weak elevated instability in the
vicinity of the cold frontal passage. It would be preferred however
to have some solid upper level divergence to get thunderstorms
going. As a result, they have been left out of the forecast for now
based on the progged position of the upper jet in the 12Z data. If
the jet streak ends up further south, they may need to be
reintroduced to the forecast.
There remain some questions for Monday. The GFS continues to bring a
system through with some snow and rain. The ECMWF is now clipping
the southern portion of the forecast area. Considering the system is
currently near Barrow, Alaska, model agreement is actually pretty
good. Chances for precipitation have been set at 30 percent for this
event.
The pattern then shifts again with southwesterly flow aloft
developing Tuesday and Wednesday. The timing of the warm front and
associated low are progged in the Tuesday night and Wednesday period
per the model consensus, so chances for rain have been included in
the forecast.
&&
.AVIATION /03Z THURSDAY THROUGH MONDAY/...
High pressure off the Mid Atlantic coast will produce a weak onshore
flow across the terminals overnight through Thursday.
IFR to LIFR ceilings along with MVFR to IFR fog has developed across
Long Island this evening. Other areas were VFR. Fog and stratus is
expected to expand north and west with the NYC area terminals
becoming MVFR and possibly at times IFR. And after 06Z coastal, y
Connecticut into the lower Hudson Valley becomes MVFR to IFR.
MVFR to IFR remains into Thursday morning with conditions improving
to VFR by late morning into the afternoon. Along the coast possible
that conditions remain MVFR through much of the afternoon. Timing of
improvement is uncertain at this time.
Conditions lower once again after 23Z Thursday.
Light and variable, to calm, winds at all terminals overnight, then
becoming S-SW Thursday.
.OUTLOOK FOR 00Z FRIDAY THROUGH MONDAY...
.Thursday night-Saturday...MVFR to IFR in stratus and fog.
Likely improving to VFR during the day Friday before lowering
again Friday night. Chance of light rain or drizzle.
.Saturday night...MVFR likely with rain. Gusty S winds becoming NW.
.Sunday...VFR...Gusty NW winds.
.Monday...VFR early...becoming MVFR. Chance of rain or snow.
&&
.MARINE...
Might need to eventually issue a dense fog advisory for tonight
should it become more obvious that dense fog becomes more
widespread.
Otherwise, high pressure over the western Atlantic brings a
weak pressure gradient and rather tranquil conditions to the
local waters through Thursday night. Southerly wind gusts on the
ocean could increase to close to 20 kt Thursday afternoon and
evening. A southerly swell may also bring ocean seas to near 4
ft Thursday night. Otherwise, sub-sca conditions are expected.
Winds and waves will remain below Small Craft Advisory levels
Friday. Conditions will deteriorate Saturday, with criteria likely
to be achieved Saturday night after a cold frontal passage. Small
Craft Advisory conditions are then likely on Sunday, and possible on
Monday. Winds and seas improve on Tuesday.
&&
.HYDROLOGY...
No hydrologic impacts are expected through Friday. Around an
inch of rain is possible Saturday and Saturday night. Measurable
precipitation is possible Monday and again Wednesday of next
week.
&&
.OKX WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...None.
NJ...None.
MARINE...None.
&&
$$
SYNOPSIS...12/DS
NEAR TERM...JC/DS
SHORT TERM...DS
LONG TERM...12
AVIATION...IRD/MET
MARINE...12/JC/DS
HYDROLOGY...12/DS
Area Forecast Discussion
National Weather Service Pocatello ID
842 PM MST Wed Feb 22 2017
.UPDATE...
Monitoring a band of heavy snow that is working its way up the
Snake Plain this evening. This band has been putting out around an
inch or so of snow but has been progressive. The center of the low
pressure appears to be based somewhere near Twin Falls on radar.
They`ve seen more steady snow this evening. This low will slowly
move east tonight and into Friday morning. Still think the best
snowfall amounts of 2 to 4 inches around Burley seem reasonable
through midday Friday. Higher amounts are possible south of there
where terrain will help to add to snow intensity. Increased
chances further north from Sun Valley to Idaho Falls as this band
of snow lifts northward. Once again expecting around an inch,
although wouldn`t be surprised if Sun Valley sees something closer
to 2 or 3 inches because of the terrain helping to increase lift
in the area. Will leave all advisories alone and amounts in the
advisories/warnings alone. 1 to 3 is likely through noon Friday
around Pocatello and around 1 around Idaho Falls. Low to medium
confidence in these amounts as the models are still trying to hone
in on the qpf amounts with this system. The update tonight was
heavily based on the HRRR which seem to better depict individual
elements with each hour (for example the progression of the band).
The new NAM may actually be somewhat reasonable although the qpf
amounts in the bands are way way overdone.
Valle
&&
.PREV DISCUSSION... /issued 224 PM MST Wed Feb 22 2017/
SHORT TERM...Tonight through Friday. Strong shortwave driving
across Nevada this afternoon per satellite imagery. Good moisture
north of circulation with cooling cloud tops in area of increasing
divergence aloft in southern ID. Models greatly increase the
amount of divergence aloft through the remainder of the evening,
then rotate region north into Snake Plain and weakening it through
the rest of tonight. Surface low still expected to rapidly deepen
near the state line this evening, but model consensus
considerably weaker on exact positioning of surface features
overnight. this is problematic because while divergence aloft will
drive much of the upward motion, snowfall overnight will likely
be enhanced by orographics driven by the lower level features.
Regardless, there is quite a bit of model consensus that a strong
band of snow fall will develop over the southern highlands then
develop/swing northeast into the Caribou highlands overnight.
Snowfall max extend into the Snake Plain as well. Consensus puts
several inches of snow fall along I-84/I-86 corridors along with
the southern highlands but there is much less agreement on whether
significant snow will develop much farther north than Pocatello.
First shortwave drives east during the day Thursday but inverted
700mb and surface trough remain draped over region Thursday
through early Friday with flow favorable for orographically
enhanced snowfall to continue. Current estimates maintain snow
amounts sufficient to provide significant impact on travel through
the region mainly across the southern portions of the forecast
area. There is much lower confidence on significant snows reaching
as far north as Idaho Falls, but given divergence of model
solutions cannot quite rule out yet. Have maintained previously
issued advisory headline, but also added the Pocatello region.
Have also upgraded IDZ022 to winter storm warning to support
higher snow amounts above 6000 ft. If system develops as expected,
more regions could be upgraded to warnings as well. DMH
LONG TERM...Saturday through Wednesday. Saturday will start off
mild but quickly become snowy with a series of shortwaves passing
through the region over the weekend. Snow accumulations are expected
to be light overall, with anywhere from 1 to 4 inches expected
across the mountains and along the Continental Divide. Snake
Plain regions may see a light dusting as well. Temperatures both
days will be in the mid 20s to low 30s for highs with areas below
0 for minimum temperatures in the Central Mountains and Bear Lake
regions. Late Sunday into Monday will bring a widespread wet
period with an anticipated closed low approaching from the
southwest. Snow is expected Monday morning through early Tuesday
across the region. Winds are expected to increase Tuesday into
Wednesday in response to a passing shortwave behind the main low.
Additionally, light snow is possible across Southeast Idaho with
low confidence in occurrence either day. NP/DMH
AVIATION...VFR conditions expected until the late evening/overnight
hours due to approaching trough. Ceilings will then lower to MVFR
through tomorrow with snow or a mix or rain and snow at BYI, PIH and
SUN. IDA and DIJ are not expected to be impacted by SN until
tomorrow morning. Winds are not forecast to be of impact today
either. NP/DMH
HYDROLOGY...Moderate precipitation amounts and mild low to mid elevation
temperatures the past several days have maintained and worsened low
land flooding threat across the region. Minidoka, Lincoln, Oneida,
Franklin, Southwest Bingham, and Southwest Caribou counties have, in
particular, seen increased low land flooding where flood warnings
are in effect. Some minor low land flooding has continued for
Western Caribou, Eastern Bingham, Western Jefferson and Madison
counties where flood advisories remain in effect. Some rises have
been seen in area creeks as well as some small responses to rivers.
Goose creek from the Utah line to the Oakley reservoir has continued
to have significant flooding where a flood warning is also in
effect. The Raft river continues to have minor low land flooding
from Utah to the Snake River where a flood advisory is in effect.
Have also continued the flood warning for the Portneuf River at
Pocatello. The river is at minor flood stage currently and cresting
below moderate stage tomorrow afternoon before dropping below flood
stage on Saturday.
A cool down today through most of the weekend will aide to the slow
down of some flooding particularly for Northern areas, though it may
take some time to see the full effect. Though cooler temperatures
are expected to move into the area today into tonight, several
inches of snow is in the forecast mainly for our Southern areas
extending Northward into the Southern Snake river plain and Eastern
Magic valley. Snow will start this evening and continue through
early Friday. Temperatures will gradually start to rise Saturday and
daytime temperatures will approach the low to mid 30s for our
Northern areas and low 40s for our Southern areas Monday which will
aide to melting.
Wyatt
&&
.PIH WATCHES/WARNINGS/ADVISORIES...
Winter Weather Advisory until 11 AM MST Friday for IDZ017-021-
023>025.
Winter Storm Warning until 11 AM MST Friday for IDZ022.
&&
$$
Area Forecast Discussion
National Weather Service Springfield MO
526 PM CST Wed Feb 22 2017
.SHORT TERM...(This evening through Thursday)
Issued at 239 PM CST Wed Feb 22 2017
Stubborn fog and cloud cover this morning held temperatures down
slightly this afternoon. Mid afternoon temperatures ranged from
near 70 over the eastern Ozarks to the upper 70s across far
western Missouri and southeast Kansas. Short term guidance like
the HRRR and RAP show some patchy fog developing again late
tonight across south central Missouri into the eastern Ozarks.
Will mention this but do not think it will be widespread or dense
like last night.
A front will try to slip southward tonight but stall out as it
reaches the Central Missouri area then lifting back northward
tomorrow morning. Model guidance show a slight chance for a shower
or two developing across eastern Kansas and moving northeastward
across west central Missouri tomorrow morning.
Surface low pressure begins to develop and deep across western
Kansas Thursday afternoon. Breezy southerly winds and very warm
temperatures will be in store for the entire area Thursday
afternoon.
.LONG TERM...(Thursday Night through Wednesday)
Issued at 239 PM CST Wed Feb 22 2017
A potent storm system will track northeastward across the Upper
Midwest on Friday. A dryline followed by a cold front will move
through the area on Friday. With limited moisture and a strong
elevated mixed layer, rain chances will be very slim to none with
the passage of the front. There will be a locally significant
grassland fire weather concern Friday afternoon with RH values
dropping and gust westerly winds. Future trends will need to be
monitored for possible headlines. Wind gusts may approach up to 40
mph Friday into Friday evening.
Cooler weather will follow Friday night through the weekend with
almost a 30 to 40 degree temperature drop compared to Thursday`s
temperatures. Overnight lows will be in the mid 20s and highs in
the 40s and 50s. Another fast moving mid level wave will move
across the area Sunday night into Monday. This will bring a good
chance for light rain.
Another storm system will develop across the Central Plains
region on Thursday. This potential storm system might be something
to keep an eye on with moisture quality and instability from the
Gulf of Mexico along with upper level dynamics. There will be the
potential for thunderstorms but too early to say if any threat for
strong storms at this time. Storm total rainfall early next week
may range between 0.5 to 1.5 inches which is desperately needed
around this area. Temperatures will warm up early next week
followed by another cool down mid week.
&&
.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
Issued at 522 PM CST Wed Feb 22 2017
For the 00z TAFS...Should have mostly clear sky through the
evening. May see some lighter fog develop overnight into Thursday
morning, but not as bad as past couple of nights. Fog should burn
off by mid morning and will start to see gustiness develop at the
surface with pressure gradient increasing ahead of next low.
&&
.CLIMATE...
There will be the potential for additional record highs through
Thursday with highs in the middle to upper 70s...
Record HighsFeb 22nd Feb 23rd
Springfield 76/1995 79/1982
Joplin 87/199679/1982
Vichy- Rolla76/1995 81/1982
West Plains 74/1988 82/1996
&&
.SGF WATCHES/WARNINGS/ADVISORIES...
MO...NONE.
KS...NONE.
&&
$$
SHORT TERM...Griffin
LONG TERM...Griffin
AVIATION...Lindenberg
CLIMATE...Griffin