Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 12/14/16
Area Forecast Discussion
National Weather Service Albany NY
915 PM EST Tue Dec 13 2016
.SYNOPSIS...
A series of cold fronts will move across the region this week
ushering in colder and colder air. It will be bitterly cold Thursday
and Friday. Lake effect snows will develop Wednesday and will impact
the southern Adirondacks into Thursday night. Lake effect snow will
impact the western and central Mohawk Valley Wednesday night and
Thursday. In addition, another widespread snowfall is expected late
Friday night and Saturday morning.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
As of 915 PM EST...Regional and local radar reveal a southwest to
northeast oriented band of snow across the southern 2/3rds of the
CWA. However, not all of this was reaching the ground. Per NY
MESONET observations, it was snowing across the higher terrain but
valley locations were flurries or no snow. Dewpoint depressions in
the valley were still 5 degrees or greater which is resulting in
virga for many of these areas. Per the IR satellite imagery, cloud
tops have been warming the past couple of hours and strung area of
vorticity becomes increasingly less advective. HRRR continues to
support a diminishing trend in coverage and intensity as we will
continue with a decrease as well in the PoPs/Wx grids. Meanwhile,
polar vortex was clearly evident on this evenings H2O vapor imagery
just south of James Bay. As pieces of cold frontal passages
commences, lake effect will increase downwind of Lake Ontario
overnight.
With the passage of the cold front winds will shift to the west and
colder air will begin to be ushered in overnight. Expecting
temperatures to bottom out in the teens to upper 20s.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH THURSDAY NIGHT/...
Lake Effect Snow Watch has been issued for northern Herkimer and
Hamilton counties for Wednesday afternoon through late Thursday
night.
Turning much colder with the bitterly cold air arriving Wednesday
night into Thursday.
With arrival of the colder air will come the development of lake
effect snows down wind from lake Ontario. The low level flow will
be southwesterly as another cold front will be on the approach from
the Great Lakes region. This will result in the initial the focus
for the lake effect across the Tug Hill Plateau and the northwestern
corner of our forecast area in the western Adirondacks.
The lake effect will shift southward Wednesday night especially late
as the low level flow shifts with the passage of the next cold
front.
Expecting good inland extent with this event since will have a multi
lake connection. Have posted a lake effect watch for northern
Herkimer and Hamilton counties. Based on current forecast may need a
advisory for northern Warren county.
Looking at westerly flow Thursday with a shift to the northwest
Thursday night with the passage of yet another boundary/reinforcing
shot of colder air. The focus will be across the western
Adirondacks into the foothills and into the western and central
Mohawk Valley. Outside the current watch area lake effect snow
advisories may be needed for the adjacent counties. Have highlighted
in our hazardous weather outlook.
With passage of each front a colder airmass will be ushered wit the
coldest airmass of the season arriving Wednesday night into Thursday.
The coldest night will be Thursday and day Friday with temperatures
20 to 25 degrees below normal. Guidance has a cold pool of -20 to -30
degrees celsius at 850 mb moving across the area Thursday night. In
addition to the bitterly cold air winds will be brisk and gusty
especially Thursday afternoon and evening causing dangerous to
possibly life-threatening winds chill conditions. Based on the
current forecast looking at wind chill readings well below zero;
generally -15 to -30 degrees. Based on this wind chill headlines
will likely be needed. Also highlighted in our hazardous weather
outlook.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
The period starts out Friday morning with the entire region under
the grips of the coldest air mass of the season thus far, with
frigid conditions in place. Any wind chill advisories will likely
persist well into the morning hours due to the very cold
temperatures and a northwest breeze persisting. It will be a dry and
cold day, with dangerous wind chills finally abating by afternoon.
Highs will only be in the single digits across the higher terrain
with teens in the lower elevations. Wind speeds will also decrease
during the afternoon, making it feel slightly less bitter.
High pressure will quickly move from near the mid Atlantic coast
Friday evening to well eastward off the coast by early Saturday
morning as a warm front approaches from the south. This warm front
will be associated with a developing storm system over the central
plains and Missouri valley region. Fairly strong isentropic lift
will develop and eventually allow snow to fall and reach the ground
sometime before sunrise Saturday. Thermal profiles will be more than
cold enough for snow at the onset and through at least Saturday
morning. This will result in a few to perhaps several inches of snow
accumulation by Saturday afternoon.
Then Saturday afternoon and evening, warmer air aloft will rush in
courtesy of a strengthening southerly low level jet as low pressure
tracks northeast into the eastern Great Lakes region. This will
result in a complex thermal profile with snow likely transitioning
to a wintry mix of sleet and/or freezing rain, and eventually rain
for much of the area by Sunday morning. Duration for each precip
type still very uncertain at this time, but there is the potential
for significant wintry precip well into Saturday night, which could
include some icing. Forecast details and snow/ice amounts will be
refined as the event draws nearer.
Some areas will continue to have freezing rain Sunday morning,
across favored sheltered valleys north and east of Albany.
Otherwise, it will be warm enough through the column for plain rain.
However, as the low pressure center rapidly tracks into southern
Quebec, the system`s cold front will bring colder air back in from
the north and west, which could allow for a the precip to end as
period of snow Sunday afternoon. Potential for some snow Sunday will
be mainly across the higher terrain north and west of the Capital
District.
Much colder air will filter back into the entire area Sunday night
behind the cold front. High pressure is forecast to quickly build in
by Monday, so it appears the lake effect potential will be limited
for early next week. After a warm day Sunday, temperatures are
expected to cool back to below normal readings for Monday and
Tuesday.
&&
.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
VFR conditions into early this evening, then MVFR conditions with
light snow and lower CIGS tonight into the early overnight period.
Guidance show a chance for IFR conditions in snow shower activity
between 02-06Z, however confidence remains within the MVFR
thresholds at this time. VFR conditions should return around 12Z
and then continue through the end of the forecast period.
Winds will remain light out of the south/southwest this evening
before turning westerly. Wind speeds will increase to between 5-10
knots Wednesday morning with higher gusts.
Outlook...
Wednesday Night: Moderate Operational Impact. Chance of SHSN.
Thursday: Moderate Operational Impact. Chance of SHSN.
Thursday Night: Moderate Operational Impact. Chance of SHSN.
Friday: No Operational Impact. NO SIG WX.
Friday Night: Moderate Operational Impact. Likely SN.
Saturday: High Operational Impact. Definite SN...SLEET.
Saturday Night: High Operational Impact. Likely RA.
Sunday: High Operational Impact. Likely RA...SN.
&&
.HYDROLOGY...
No hydrologic problems forecast through the weekend. Ice will build
and thicken on area rivers and lakes later as series of cold fronts
move across the region ushering in colder and colder air. It will be
bitterly cold Thursday and Friday.
Lake effect snows will occur downwind of Lake Ontario Wednesday
through late Thursday night. A widespread snowfall is expected
late Friday night into Saturday. However warmer air is expected
work in initially aloft resulting in a wintry mix of precipitation
with a changeover to rain Saturday night. Colder air will be
ushered back in on Sunday.
For details on specific area rivers and lakes, including observed
and forecast river stages and lake elevations, please visit the
Advanced Hydrologic Prediction Service /AHPS/ graphs on our
website.
&&
.ALY WATCHES/WARNINGS/ADVISORIES...
CT...None.
NY...Lake Effect Snow Watch from Wednesday afternoon through late
Thursday night for NYZ032-033.
MA...None.
VT...None.
&&
$$
SYNOPSIS...IAA
NEAR TERM...IAA/BGM
SHORT TERM...IAA
LONG TERM...JPV
AVIATION...BGM/Thompson/JVM
HYDROLOGY...IAA
Area Forecast Discussion
National Weather Service State College PA
613 PM EST Tue Dec 13 2016
.SYNOPSIS...
A disturbance will bring a period of snow to central and northern
Pennsylvania this evening, followed by a brief period of tranquil
weather later tonight into Wednesday. A blast of arctic air will
arrive late Wednesday and Thursday bringing frigid air that will
last through Friday. A new frontal system will bring the next
chance for rain or snow this weekend.
&&
.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
Snow is breaking out over southern Pa. Latest HRRR continues the
idea of banded precip setting up under a region of strong
frontogenetic forcing associated with a vigorous jet streak that
is going to slide through the region.
Snow will continue to overspread the rest of the forecast area
through the first half of the evening. Expect the snow to start
tapering off by mid evening.
It looks good for a stripe of 1-3 accums in the northeast up over
the middle and upper Susq Valley.
&&
.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH 6 PM WEDNESDAY/...
Breezy conditions will prevail Wednesday as the nose of the
surface high pokes east and brings basically fair weather to the
bulk of the CWA. The best chance for some snow showers will be
over the NW where upslope and lake moisture always seem to
conspire to bring clouds and precip this time of year. It looks
like the latest timing holds the arctic front north of the area
until overnight Wednesday.
Highs Wednesday will struggle to reach 20F northwest...and range
to the mid to upper 30s across the southeast.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH TUESDAY/...
Strong zonal flow pattern across the conus will buck southward
over the next several days as the first Arctic blast of the
season moves across the Northern Plains and east into the
northern mid Atlantic region. Thursday and Friday will feature a
gusty west to northwest wind, frequently in excess of 30mph. Some
gusts around 40mph are likely.
Numerous snow showers and scattered squalls will be over the
region Thursday. Temps Thursday could conceivably stay in the
single digits across the higher terrain of the NW mtns and Laurel
Highlands. The GEFS shows a large area of -2 to -3 sigma temps at
850 mb with min values around -20 F.
Gusty West-Northwest wind accompanying the cold air will create
below zero wind chills for much of the region Thu morning and
only in the single digits during the daylight hours. Skies will
become mainly clear with the wind dying off Thursday night as a
1025 mb sfc high build east from the nation`s heartland. Min
temps early Friday could dip to zero to 5 below across the fresh
snow covered ground of the Laurel Highlands and NW mtns, and will
be in the single digits to teens across the Central and SE zones.
Fair and dry (but very cold) weather is expected to persist Friday
and Friday night. However, a moisture-laden storm will likely
impact a large chunk of the region (beginning Friday night or
Saturday) with snow changing to mixed precip or rain from the SW
as a strong and rapidly warming southerly jet overruns the colder
surface air (850mb temps may rise as much as 20-25C over a 36hr
period from 12z Fri through 00z Sun). Although it`s still too
early to give specifics on that storm w/resp to snowfall, both the
EC and GEFS do show the parent storm heading NE from the mid
Mississippi to the Upper Great Lakes. Since this storm track is so
far to the NW, the deep valleys in Central PA could easily trap
the cold, sub- freezing air into Saturday afternoon, bringing a
slower or only partial changeover further north and east.
As trough on back side of this system lifts across the Great
Lakes, could see a period of light snow Sat night before high
pressure builds in again on Sunday.
&&
.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
The snow has now arrived over central and western airfields, with
conditions dropping into the IFR to LIFR at times in the heavier
bursts of snow. Southeastern airfields remain VFR...with
precipitation moving into this area a little later in the evening,
where a mix of snow and rain is expected.
The snow will tend to move through quickly with precipitation
tapering off between 04-06Z.
Patchy Freezing Drizzle is possible at JST/BFD late tonight into
early Wed morning, but confidence is too low to include in the TAF.
Winds shifting to the west should allow for improving conditions
in the lee of the Alleghenies with VFR likely returning to
AOO/UNV/IPT. ceilings after midnight, but MVFR will likely
persist at BFD/JST.
On Wednesday JST/BFD stand the best chance of remaining sub VFR
through at least the first half of the day. The remaining
terminals will be VFR with a gusty west wind.
Outlook...
Thu...MVFR/IFR with frequent snow showers west; MVFR to low VFR
ceilings central and east with ocnl snow showers and flurries.
Becoming windy with 25-35kt gusts from 270-300. Snow squalls
possible with arctic fropa Wednesday night/early Thursday.
Fri...Decreasing winds. No sig wx.
Sat-Sun...MVFR/IFR. Wintry mix to rain. Increasing winds from the
south with LLWS likely into Saturday night.
&&
.CTP WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SYNOPSIS...La Corte
NEAR TERM...La Corte/Ceru
SHORT TERM...La Corte
LONG TERM...Gartner/RXR
AVIATION...Jung/La Corte
Area Forecast Discussion
National Weather Service Dodge City KS
542 PM CST Tue Dec 13 2016
...Updated aviation discussion...
.SHORT TERM...(This evening through Wednesday)
Issued at 230 PM CST Tue Dec 13 2016
The HRRR has had a great trend for temperatures today. As decent
cold advection continues behind the cold front, we are likely to
finish out this afternoon in the mid/upper 20s over central
Kansas to around the mid 30s in extreme southwest. Occasional cirrus
will be all that we expect cloud-wise through the evening,
especially toward morning, having little impact on overnight lows.
Generally steady to slowly falling temperatures to the teens in
central KS to around 20 far southwest. Surface winds may swing to
the south only briefly before another reinforcing surface cold
front pushes in from the northwest tonight. As a result, brisk
northeast surface winds are forecast Wednesday. With an overall
lack of temperature tendency, models only bring highs to around
the freezing point Wednesday afternoon.
.LONG TERM...(Wednesday night through Tuesday)
Issued at 230 PM CST Tue Dec 13 2016
The main focus in the extended will be the major swing from very
warm conditions to, possibly even near record cold in a few
locations by early Sunday morning. with Thursday bringing a return to
southerly winds and a warming trend, even much warmer air will
develop on Friday as warm 850 mb air descends to the lower Plains.
Central Kansas counties (Hays area), while still near or above
normal for mid December, will probably be somewhere in the 40s,
with 70s looking likely along the Oklahoma line. There will be a
broad gradient of highs. By the evening or overnight however a
cold will blast through the area, bring a long 24 hour period at
least of very strong cold advection on very strong boundary layer
winds. A digging shortwave will be present to aid forcing for
ascent. The EC shows potential for QPF of a couple of tenths,
with a snow thermal profile, and if enough piles up driving/travel
impacts can`t be ruled out. The GFS suggests lesser amounts of QPF.
Wind chills may be significant on Saturday night as well with
gradient winds holding up.
&&
.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 542 PM CST Tue Dec 13 2016
VFR conditions are expected to prevail through this period. Light
and variable winds will continue through the night. Another surge
of Arctic air will push into western Kansas on Wednesday morning.
This will bring increasing northeast winds to the terminals with
gusts to 20-25 kts possible by late morning and afternoon.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 16 30 13 34 / 0 10 0 0
GCK 15 29 13 39 / 0 0 0 0
EHA 22 32 15 53 / 0 0 0 0
LBL 19 32 15 45 / 0 0 0 0
HYS 13 29 13 31 / 0 10 0 0
P28 19 34 15 33 / 0 0 0 0
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Russell
LONG TERM...Russell
AVIATION...Gerard
Area Forecast Discussion
National Weather Service Green Bay WI
543 PM CST Tue Dec 13 2016
Updated aviation portion for 00Z TAF issuance
.SHORT TERM...Tonight and Wednesday
Issued at 309 PM CST Tue Dec 13 2016
The latest RAP analysis and satellite/radar imagery show arctic
high pressure centered over the central Great Plains early this
afternoon. This arctic high is producing clear skies across much
of the region, except downwind of the Great Lakes and also over
northern Minnesota. Temps and wind chills have been slow to
recover so far today, especially over n-c WI where wind chill
indices are mostly between 10 and 15 below zero. Though there are
scattered clouds upstream over northern Minnesota, the main
forecast concern revolves around temps and wind chills.
Tonight...Arctic high pressure will be expanding east into the
northern Ohio Valley. Between this high and and low pressure over
northern Ontario, will have a tight pressure gradient in place,
which will generate breezy southwest winds. Scattered to broken
clouds may push into north-central WI late this evening and
overnight, but they are still a long way off and may struggle to
move into the region, let alone have a significant impact on
temps. So with breezy winds, temps have little chance of
plummeting and lows should remain between 5 below and 5 above. But
with the wind chills though, apparent temps will hover between 15
and 25 below zero over central and north-central WI, and 5 to 15
below elsewhere. Will issue a SPS to cover near advisory criteria
wind chills.
Wednesday...The low wind chills will continue through the late
morning hours across north-central WI. Otherwise, should have more
in the way of cloud cover due to steep low level lapse rates and
some moisture around 850mb. West winds will be more gusty, with
some gusts between 25 and 30 mph. Combined with high temperatures
similar to todays readings, wind chills will struggle to rise
above 10 below, except near the Lakeshore.
.LONG TERM...Wednesday Night Through Tuesday
Issued at 309 PM CST Tue Dec 13 2016
Two big stories in the long term. First, arctic air will remain
in place through Thursday night, with another arctic blast on
Sunday/Monday. Second, confidence growing for a winter storm
Friday PM into Saturday.
Arctic airmass will remain in place Wednesday night through
Thursday night, with highs in the single digits above zero for
most spots, except a few spots reaching 10-13F across eastern WI
on Wednesday. Lows Wednesday and Thursday nights will be below
zero for all but near Lake Michigan. Thursday night lows will
hinge on how fast clouds increase overnight. If we stay clear,
low temps could plummet. Wind chill headlines will be needed for
most of the area Wednesday night as wind chills drop between -15
and -30F (coldest across central and north central WI). As winds
die off Thursday night, wind chill headlines may not be needed.
Lake effect snow showers will be ongoing across far north central
WI Wednesday night and continue into Thursday morning. The bulk of
the accumulating snow will stay in the U.P., as winds stay WNW,
but some light accumulations are possible closer to the MI border.
Attention turns to the approaching winter storm. Models continue
to signal a significant snow event for the area Friday PM into
Saturday, but details on timing, strength, and consistency run to
run remain issues. Overall on the larger scale, models are similar
showing surface low pressure organizing in the central Plains
Friday night, then tracking NE into lower Michigan Saturday
afternoon/evening. Aloft, a digging trough will cross the northern
Plains on Saturday and over the Great Lakes Saturday night into
Sunday and a 160+ kt jet developing just east of WI Saturday
night. Models all show a impressive warm air advection band of
snow ahead of the developing low pressure, with the ECMWF actually
the bullish on snow totals with this event. GFS/ECMWF/Canadian
differ on timing and just how strong the surface low gets as it
moves into lower Michigan, which will impact start/end times and
snow totals. ECMWF continues to be the most progressive/weak with
the system, with the Canadian now the strongest/slowest. GFS is
closer to the Canadian. Even with timing and minor forcing
differences, the 3 models actually produce similar QPF amounts,
with over 0.5" for all locations. Highest amounts continue to be
farther south, with around 0.9" of liquid by early Sunday morning.
Amounts pretty impressive with the warm air advection but could be
lacking on the back side if the system does not deepen enough to
produce a deformation zone. If we get the max amounts from the
warm air advection plus a deformation zone, snow totals could
really add up.
Some details still to be worked out with this system but the
bottom line is we are expecting a significant snowfall for the
area starting Friday afternoon and continuing into at least
Saturday morning, possibly into Saturday afternoon and evening.
Using snow ratios of 15:1 to 20:1 (could even be higher), 6+
inches of snow seems likely for most or all of the area, with
totals over 10 inches a good bet somewhere, especially the
farther south you are. Winds do not look overly impressive, but
even gusts to 20 mph could produce some minor blowing and drifting
snow as the snow looks to be light and fluffy. The storm will be a
prolonged event, over a 24-36 hour period, but winter headlines
will be needed eventually as this system will have travel impacts
Friday afternoon into Saturday.
Lake effect snow will continue on the back side of the system
Saturday night and Sunday, bringing additional accumulations to
north central WI. Another surge of arctic air will surge into the
area behind the system, with single digits highs and sub-zero lows
expected Sunday into Monday.
&&
.AVIATION...for 00Z TAF Issuance
Issued at 542 PM CST Tue Dec 13 2016
METARS ARE MISSING ACROSS MUCH OF THE NATION FROM 20Z
UP UNTIL THIS WRITING (2330Z) DUE TO A COMMUNICATIONS CENTER FIRE
IN NEBRASKA. NOT SURE WHEN THEY WILL RETURN.
WEATHER WISE NOT MUCH TROUBLE TONIGHT AND WEDNESDAY WITH MAINLY
CLEAR SKIES EXCEPT FOR SOME SCATTERED CLOUDS WITH BASES AROUND
3500 FEET IN THE NORTH. LOW LEVEL WIND SHEAR MAY AFFECT SOME
AIRCRAFT AFTER 03Z TONIGHT THROUGH 14Z WEDNESDAY WITH 35 KNOT WEST
WINDS AT 1000 FT AGL AND SOUTHWEST WINDS AROUND 10 KNOTS AT THE
SFC.
A SIGNIFICANT SNOW IS LIKELY FRIDAY AFTERNOON THROUGH SATURDAY,
REQUIRING PLOWING OF RUNWAYS, TAXIWAYS, RAMPS AND PARKING LOTS.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM.....MPC
LONG TERM......Bersch
AVIATION.......RDM
Area Forecast Discussion
National Weather Service Jacksonville FL
829 PM EST Tue Dec 13 2016
.UPDATE...
Currently favoring the HRRR Model for the overnight period over
the NAM12 which is much slower in moving precipitation into the
area tonight.
A frontal system will approach the area tonight and Wednesday
with showers and thunderstorms ahead of it moving from the WSW to
the ENE. The greatest concentration of showers will be over
Georgia overnight with a locally dense fog bank developing over
the north Florida Peninsula. Cross City...CTY...is already down
to 1/2 mile in fog with a cloud layer at 200 feet so we might
need a Dense Fog Advisory for areas south of I-10 later tonight.
Right now will hold off to see how things progress but if it looks
like we might need it will try to get it out before 11 EDT. The
showers and thunderstorms should approach the Jacksonville Metro
area around 1-3 a.m. and should diminish toward the morning
commute.
&&
.AVIATION...A line of showers and thunderstorms will move across
south Georgia and extreme north Florida tonight and early
tomorrow morning. The band will break up over north Florida and
drop south through 1800 utc. Between the rain and fog visibilities
will be below 1sm at times with ceilings in the 500-1500 foot
range toward morning. Fog should sock in the Gainesville area by
0200 utc and continue through most of the night. Wednesday should
see clearing conditions over Georgia with low clouds hanging in
most of the day over Florida.
&&
.MARINE...A cold front will then push through the waters
Wednesday and Wednesday night with showers and thunderstorms ahead
of it. High pressure will then build to the north of the region
through the end of the week with a wedge/local northeaster
developing by late week. Small craft advisory conditions are
possible, mainly due to seas, on Friday and Saturday.
Rip Currents: Low risk through Wednesday.
&&
.PRELIMINARY POINT TEMPS/POPS...
AMG 61 67 48 61 / 70 70 20 0
SSI 62 69 52 62 / 50 60 40 0
JAX 61 73 54 65 / 30 60 20 0
SGJ 61 74 57 65 / 10 30 20 10
GNV 60 75 55 69 / 10 30 20 10
OCF 61 76 58 71 / 10 20 20 10
&&
.JAX WATCHES/WARNINGS/ADVISORIES...
FL...None.
GA...None.
AM...None.
&&
$$
Sandrik/Hess/Walker