Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 12/30/22
Area Forecast Discussion
National Weather Service Caribou ME
929 PM EST Thu Dec 29 2022
.SYNOPSIS...
A warm front will slowly lift across northern Maine through
tonight, then remain north of the region through Saturday.
Low pressure will cross the region Saturday night through early
Sunday, then exit across the Maritimes later Sunday. High
pressure will cross the region Monday. A warm front will lift
north Tuesday.
&&
.NEAR TERM /THROUGH FRIDAY/...
930 PM Update: Just minor chgs to cld cvr, msly to xtnd cldy
skies swrd thru Downeast areas for the time being based on
latest sat imagery trends. Otherwise, fcst hrly temps/dwpts
have been updated into the late ngt hrs from latest sfc obs with
no chgs in fcst ovrngt lows attm.
Prev Disc: The low pressure system over the Great Lakes will
continue to push a warm front into the region tonight and into
Friday. High- res models show some lingering snow showers across
St John Valley in the late evening, but quickly diminishing
before midnight. Upper air model soundings still point to a
period of freezing drizzle with possible flurries tonight, but
will remain in the far north. Areas south of Central Aroostook
will not see this freezing drizzle due to the drier air ahead of
the front. The upper air model soundings have also been
pointing to a period of patchy fog after midnight tonight as the
warm airmass starts to move into the area. The HRRR and RAP
indicate patchy fog from Downeast up to Central Aroostook, while
the NAM shows a fairly dry airmass. The SREF maps show higher
prob for low ceilings and visibility in Downeast and along the
eastern border. Decided to go with the SREF and added patchy fog
until Friday morning.
By Friday, fog could still be an issue in the early morning with
the warm air overrunning the cold snowpack. This will most
likely be in the form of very shallow fog and only a risk for
snow covered areas. By sunrise, the fog is expected to burn off.
The 925mb temps show the warm air pushing in by the early
morning and rapidly warming temps throughout the day. Expect
temps to be in the 40s across the region.
&&
.SHORT TERM /FRIDAY NIGHT THROUGH SUNDAY/...
A warm front lifts north of the region Friday night. Expect mostly
cloudy skies with a chance of rain showers across northern areas
Friday night. Warmer air across the snowpack will also support
patchy fog. Mostly cloudy skies are expected Downeast Friday night.
Low pressure will lift to the Great Lakes Saturday, while
unseasonably warm air remains across the region. Expect mostly
cloudy skies along with a chance of rain showers and patchy fog will
persist across northern areas Saturday, with mostly cloudy skies
along with a chance of mostly afternoon rain showers Downeast.
The low will track to Maine Saturday night with a steady rain
expanding across the forecast area. The intensifying low will
exit across the Maritimes later Sunday. Rain will persist early
Sunday. Colder air will be drawn across the region in the wake
of the exiting low later Sunday. This will allow a transition
back to snow or snow showers. Light snow accumulations are
possible later Sunday, mostly across the north and mountains.
Above normal level temperatures are expected Saturday into early
Sunday. Temperatures will fall later Sunday in the wake of the
low.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
Expect mostly cloudy skies along with a chance of snow showers
across the north and mountains Sunday night, Across Downeast areas,
expect mostly cloudy skies along with a chance of rain/snow showers
early then partly cloudy late. Low pressure tracks northeast across
the Great Lakes Tuesday, though the exact track remains uncertain.
The low will draw warm air back north across the forecast area
Tuesday, though how rapidly this occurs will be dependent on the
eventual track. Precipitation totals and chances Tuesday will also
be dependent on the eventual low track. Snow will transition to a
wintry mix then eventually rain Tuesday into Tuesday night across
much of the region. However, dependent on the track, a wintry mix
could persist across northern areas. Precipitation chances/types
Wednesday will depend on the eventual track of low pressure though
significant differences with the track still exist. The uncertainty
persists into Thursday regarding the track along with precipitation
chances/types. Temperatures will be at above normal levels
Monday/Tuesday. Temperatures Wednesday/Thursday will be dependent on
the eventual track of low pressure.
&&
.AVIATION /03Z FRIDAY THROUGH TUESDAY/...
NEAR TERM: IFR tonight into Fri from KPQI north with -sn
becoming -fzdz. LLWS possible Fri from KPQI North. Mainly MVFR
near KHUL tonight and Fri. VFR becoming MVFR tonight south of
KHUL. S wind 5 knots or less tonight, increasing to around 10
knots Fri.
SHORT TERM:
Friday night and Saturday...MVFR/IFR, occasional LIFR, across
the region. A chance of rain showers and patchy fog north
Friday night and Saturday. A chance of rain showers Downeast
Saturday afternoon. South/southwest winds 5 to 10 knots.
Saturday night...MVFR/IFR, occasional LIFR. Rain developing with
patchy fog. Variable winds 5 to 10 knots.
Sunday...MVFR/IFR, occasional LIFR. Rain transitioning to snow or
snow showers. Variable winds 5 to 10 knots, becoming northwest 10 to
20 knots with gusts up to 25 knots.
Sunday night...MVFR/IFR north with snow tapering to snow showers.
Across Downeast areas, MVFR/IFR with a chance of rain or snow
showers early then VFR. Northwest winds 10 to 20 knots with
gusts up to 25 knots.
Monday...VFR/MVFR with a chance of snow showers north, VFR Downeast.
West/northwest winds 10 to 15 knots with gusts up to 20 knots.
Monday night...VFR. Variable winds 5 to 10 knots.
Tuesday...VFR early, lowering to MVFR/IFR with snow or a wintry mix
developing. Variable winds 5 to 10 knots, becoming south/southeast
10 to 15 knots with gusts up to 20 knots.
&&
.MARINE...
NEAR TERM: Winds and seas will remain below SCA conditions
tonight and Friday. Winds 10-15 kts and seas 1-3 ft.
SHORT TERM: Small craft advisory conditions possible Friday night into
Saturday. Conditions below small craft advisory levels Saturday
night. Small craft advisory conditions develop Sunday. A chance
of rain showers Saturday. Rain and patchy fog Saturday
night/Sunday.
&&
.HYDROLOGY...
Rainfall and warmer temperatures will combine to melt some
snowpack and raise river levels during the weekend. In most
places, rivers will remain well below flood level. Places with
current ice jams (notably Howland at this point) could see some
movement. The rising water might cause some mechanical break
up. However, if the ice holds, the influx of additional water
could lead to further flooding upstream. Snowmelt is expected to
decrease again at the end of the weekend, but it will take a
day or two for the additional water to move downstream, so the
window of potential greatest change in river levels will most
likely occur early next week.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...None.
MARINE...None.
&&
$$
Near Term...VJN
Short Term...Norcross
Long Term...Norcross
Aviation...VJN/Norcross
Marine...VJN/Norcross
Hydrology...VJN/Sinko
Area Forecast Discussion
National Weather Service Corpus Christi TX
919 PM CST Thu Dec 29 2022
...New UPDATE...
.UPDATE...
Issued at 844 PM CST Thu Dec 29 2022
The threat of showers has come to an end over Victoria Crossroads
as the mid level S/W lifts just NE of the area. Meanwhile the
threat of showers and a few storms will continue over the offshore
waters where the moisture and instability axis remains and 100kt
upper jet is nosing in. Weak surface boundary lags behind the
exiting s/w and has not shown much eastward progress in the last
few hours. As of 03z the boundary was still along the I-37
corridor. Given the moist environment ahead of the boundary expect
fog to become a problem overnight. Question is whether fog will
become dense with mid/high level overcast. SREF probabilities for
Visibilities <1 mile has lowered some but still 40-60%. The
visibility sensor at UTMSI currently measures 2 miles while
Calhoun County Airport at Port Lavaca reports 5 miles.
Concerning SCA`s, winds have diminished but seas remain high over
the offshore waters and are in the 8-10 ft range, thus will
maintain SCAs through 12z Fri when the WW3 model indicates seas
will subside <7 ft.
&&
.SHORT TERM...
(Tonight through Friday night)
Issued at 219 PM CST Thu Dec 29 2022
Key Messages:
- Isolated to scattered showers/thunderstorms possible through the
evening across Northern Coastal Bend and Victoria Crossroads.
- Patchy to areas of fog/dense fog tonight and Friday night.
- Moderate risk of rip currents tonight through early Friday
morning.
An upper level trough extending from the Northern Plains into
South Texas is expected to continue an eastward transition through
the short-term period. Ahead and along it a series of disturbances
will be tracking aloft through the area. The combination of a
developing surface low/trough over the region along with the
arrival of deeper Gulf moisture (PWATs around 1.2-1.4 inches) and
energy associated to the upper level system has lead to isolated
to scattered showers across portions of the Northern Coastal Bend
and Victoria Crossroads today. Most of the activity has remained
light through the day, but a few pockets of moderate to at times
heavy rainfall will remain possible with any thunderstorm that
develops through the afternoon. The convective activity is
expected to continue into the early evening hours before tapering
off inland and transitioning into the coastal waters. Most of the
rainfall/possible convection is forecast to remain concentrated
on the far northeastern portion of the CWA, with drier conditions
persisting elsewhere. Although confidence in occurrence is low,
portions of the Victoria Crossroads remain under a Marginal risk
of excessive rainfall from WPC through tonight.
The bulk of the energy in association with the upper level trough
will arrive tomorrow. However, not anticipating too much in terms
of showers and convection, as much drier air filter in as ridging
builds at the surface behind a weak frontal boundary. This
boundary will mainly lead to a change in wind direction and drier
conditions rather than a drastic change in temperatures.
Nevertheless, weak CAA will bring minimum temperatures down around
5-10 degrees Friday night. Lows tonight will run in the 50s, with
lows tomorrow night in the mid 40s to low 50s. Highs tomorrow are
forecast to warm into the 70s area wide.
In terms of hazards, patchy to areas of fog are expected to
redevelop overnight, with visibilities falling to dense levels or
below 1/4 of a mile at times at some locations. Areas of fog will
be possible again Friday night. A Moderate risk of rip currents is
now in effect through the rest of the afternoon and overnight due
to a moderate to strong southerly flow over the offshore waters,
swell periods around 8 seconds and 4-5 ft swells expected.
&&
.LONG TERM...
(Saturday through next Wednesday)
Issued at 219 PM CST Thu Dec 29 2022
Key Messages:
- Sea fog continues through the weekend
- Chances for showers and thunderstorms return next week
- Increased rip current risk on Monday
We start out the long term period with quasi-zonal flow aloft with
onshore flow continuing the surface. Fog will be a concern over the
weekend as low level moisture steadily increases. Radiational fog is
expected inland as skies clear overnight and condensation pressure
deficits fall to less than 2mb. A prolonged period of sea fog is
possible across the nearshore waters and bays and warm moist air
flows over the cooler shelf waters. Fog may be dense at times.
Currently expecting the fog to continue through the weekend with a
gradually clearing through the morning hours Monday as a ~25-35 knot
H85 LLJ kicks in.
As we head into the work week, a stout upper level low will dig
south across the Four Corners and lift across the Plains. A Pacific
front will be sent our way late Monday into Tuesday morning.
Moisture will pool across the region ahead of the front with inland
locations around 1.15" PWATs and slightly deeper moisture sitting
offshore. A plume of instability will nudge across the Coastal
Plains around the same time we are positioned under a favorable
quadrant of the upper level jet. This will help provide a chance for
showers and thunderstorms along and ahead of this front Monday into
Tuesday morning. Drier air will begin to work into the area behind
the front but we will hold onto some slight chances for
thunderstorms, generally along the coast and over the waters, as
several pulses of H85 vorticity eject through the region. A
secondary surge of high pressure arrives by mid week and brings an
end to any lingering rain chances.
We will need to monitor our rip current risk as we head into the
work week. A favorable increasing south-southeasterly flow and
periods around ~8s will provide a moderate to potentially high risk
of rip currents.
To touch on temperatures quickly, we will be rather warm through the
weekend with highs in the upper 70s to mid 80s with lows in the 60s.
Our Pacific front will cool us off a bit with highs falling back
into the mid 60s to mid 70. Lows will drop down into the 40s as the
drier air arrives.
&&
.AVIATION...
(00Z TAFS)
Issued at 526 PM CST Thu Dec 29 2022
Showers over the Victoria Crossroads should shift northeast of the
area in the next few hours with VFR conditions prevailing across
most of South Texas in its wake. High level (25kft) overcast will
become mid level (10kft) overcast during the evening hours as the
mid level trough moves into the area. A weak surface boundary
draped from N-S along the I-37 corridor will move slowly east
overnight. Light south winds can be expected ahead of the
boundary and light north winds behind. In advance of the boundary
areas of fog are expected to develop after midnight, likely
becoming locally dense, especially in the Victoria area where SREF
guidance indicates 80% probabilities of <1 mile visibilities.
Probs for dense fog in the CRP area are 60%. The NAM/GFS and HRRR
models also indicate dense fog tonight. Given the weak flow, Fog
will be slow to burn off on Friday but should be dissipated by 16z
as the boundary moves into the gulf and a drier NW flow develops
in its wake. Mid level (10kft) overcast conditions will persist
through the period.
&&
.MARINE...
Issued at 219 PM CST Thu Dec 29 2022
A Small Craft Advisory remains in effect for the offshore waters
through early Friday morning due to the combination of a strong
onshore flow and high seas. Winds in general will gradually
diminish tonight through Friday across all marine zones with a
weak to moderate offshore flow developing on Friday in response
to a passing frontal boundary. Isolated to scattered showers and
thunderstorms will be possible through tomorrow owing to passing
disturbances aloft. Patchy to areas of sea fog are expected to
redevelop overnight and linger through Friday morning. Periods of
sea fog will continue through the weekend and into early next
week. Visibilities may be less than a mile at times. A weak to
moderate southerly flow will return on Saturday and persist over
the weekend. Winds will strengthen on Monday with Small Craft
Advisory conditions possible ahead of an approaching cold front.
Isolated to scattered showers and thunderstorms will be possible
Monday through mid week. Offshore flow is expected behind the
front on Tuesday.
&&
.PRELIMINARY POINT TEMPS/POPS...
Corpus Christi 59 77 51 77 / 10 10 0 0
Victoria 58 74 50 76 / 30 10 0 0
Laredo 56 77 51 79 / 10 10 0 0
Alice 57 77 50 79 / 10 10 0 0
Rockport 58 73 53 71 / 10 10 0 0
Cotulla 55 75 48 81 / 10 10 0 0
Kingsville 57 78 51 79 / 10 10 0 0
Navy Corpus 61 71 57 70 / 10 10 0 0
&&
.CRP WATCHES/WARNINGS/ADVISORIES...
TX...None.
GM...Small Craft Advisory until 6 AM CST Friday for GMZ270-275.
&&
$$
SHORT TERM...JM/75
LONG TERM....TC/95
AVIATION...JM
Area Forecast Discussion
National Weather Service Peachtree City GA
750 PM EST Thu Dec 29 2022
.UPDATE...
Issued at 744 PM EST Thu Dec 29 2022
No major changes made to the forecast this evening. Forecast
remains on track for a calm and clear overnight followed the
quick deterioration of weather conditions. First CIGs will begin
to fall with patchy fog possible across central GA. Tomorrow
evening our next weather system will begin to move into the area.
&&
.SHORT TERM...
(This afternoon through Friday)
Issued at 239 PM EST Thu Dec 29 2022
High pressure at the surface and aloft will bring calm weather
conditions to the forecast area for the start of short term period.
Despite moisture return at the lower levels with a relatively weak
wedge developing along the Appalachians, a dry layer aloft is
expected to help clear out skies this afternoon. Mostly clear skies
will help today`s high temperatures climb into the upper 50s and 60s
where some locations in our southern counties may top out around 70
(10 to 15 degrees above average). As the surface high pressure
pushes off to the east and a trough over the Plains approaches the
forecast area, southwesterly flow aloft will help usher in midlevel
moisture. Clouds will fill back in overnight tonight and moderate
minimum temperatures in the upper 30s and 40s. Tomorrow, as the
trough marches eastward, the moist southwesterly flow aloft will
overrun the wedge. North and eastern Georgia could see a slight
chance for isolated light showers produced by the isentropic lift
Friday. By tomorrow evening, the onset of the next system that will
bring the bulk of the precipitation to the forecast area will begin
to approach west Georgia. A wave of precipitation will move through
the forecast area ahead of the cold front well to the west overnight
Friday and will impact the forecast area through the start of the
long term forecast period. While instability is quite limited
(MUCAPE less than 500 J/kg primarily across our southern tier and
minimal SBCAPE area wide), 30 to 40 kts of shear across western
Georgia could help maintain updrafts with thunderstorms that are
able to tap into the available instability. Additional uncertainty
over thunderstorm activity is further complicated by how the
strength of the wedge evolves throughout the short term and whether
or not the MCS models have developing over the northern Gulf will
act to limit southerly flow. With a Slight Risk for Excessive
Rainfall across a small portion of west central Georgia and a
Marginal Risk across the remainder of the forecast area, periods of
locally heavy rainfall can be expected with this wave of
precipitation. PWATs are progged between 1.0-1.5"+ through 12Z
Saturday, which will be pushing the daily max per SPC`s sounding
climatology.
KAL
&&
.LONG TERM...
(Saturday morning through next Wednesday)
Issued at 239 PM EST Thu Dec 29 2022
This longterm outlook can be broken up into two different sections
defined by two separate large scale systems. The first system is
currently well situated across the central CONUS and will continue
to work its way eastward before lifting as it approaches the East
Coast. A cold front associated with this system will bring
precipitation on Saturday, with a mode highly dependent on small
scale forcing.The second system will start to develop with
cyclogenesis over the ArkLaMiss region next Monday and may be an
efficient rain maker.
Taking a closer look at the first system, two outcomes seem
possible. The first is the solution which large scale models have
been indicated for the past few days. CAPE values of 250-500 J/Kg,
effective low level shear of ~30-40 kts, and PWATs above 1.5" may
mean thunderstorms become organized with a few becoming strong to
isolated severe. The second outcome is quite different. Short term
models, like the NAMNST and HRRR are locking onto two instability
limiting factors. These are a persistent CAD wedge across the North
and Northeast CWA and convection over the Gulf and Gulf Coast. In
this case, significant convection or even an MCS cuts/reduces
northward flow out of the Gulf. This reduction in southerly flow
means the CAD airmass in place is not scoured out effectively, mid
level support is limited, and moisture advection is reduced. This
drastically reduces convective parameters. In other words, heavy
precipitation with an isolated strong to severe threat is reduced to
widespread rain showers with a few rumbles of thunder well south of
I-20 instead. Because of this uncertainty, it is recommended to
watch for future forecasts with higher resolution models. Although,
current leaning is towards the stronger CAD and reduced southerly
flow due to large scale models` low skill in representing small
scale features and realizing convection.
Moving into the Sunday and Monday, conditions momentarily quiet down
while staying unseasonably warm. Temps range from the low 40s at
night to high 60s in the afternoon both days.
The active weather pattern picks right back up on Tuesday, when the
second system begins to develop. Model agreement is relatively high,
especially this far out, that several rounds of precipitation will
move through the area into Thursday. With significant moisture
associated with these multiple rounds of rain, storm total
precipitation from the first system will be important in analyzing
any flood threat. Because of this, details will be fine-tuned
through the weekend. Temperatures through this system will remain
similar to the weekend, with highs 10-15 degrees above average and
lows 20-25 degrees above average.
SM
&&
.AVIATION...
(00Z TAFS)
Issued at 645 PM EST Thu Dec 29 2022
VFR conditions persists this evening ahead of BKN MVFR to IFR
cigs developing around 12Z. Cigs begin to improve to MVFR and
above around 17Z. Have included a PROB30 in for ATL starting 03Z
for isolated -SHRA. Winds should remain E/SE between 5-7KT.
//ATL Confidence...Avi Update...
Medium on PROB30 timing.
High on all other elements.
28
&&
.PRELIMINARY POINT TEMPS/POPS...
Athens 41 60 50 63 / 10 10 90 90
Atlanta 43 61 53 65 / 0 10 90 70
Blairsville 39 57 48 58 / 0 10 90 90
Cartersville 42 61 52 64 / 0 10 90 70
Columbus 46 68 57 70 / 0 30 90 60
Gainesville 41 57 49 60 / 0 10 90 80
Macon 46 69 56 71 / 10 10 80 80
Rome 42 63 53 65 / 0 20 90 70
Peachtree City 42 64 54 67 / 0 10 90 70
Vidalia 50 72 57 72 / 10 0 60 80
&&
.FFC WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
SHORT TERM...28
LONG TERM....SM
AVIATION...28
Area Forecast Discussion
National Weather Service Marquette MI
631 PM EST Thu Dec 29 2022
.SHORT TERM...(This evening through Friday)
Issued at 318 PM EST THU DEC 29 2022
Latest RAP analyses show continued southwesterly flow throughout the
region and an embedded shortwave moving over IA and into MN. This is
set to drag a cold front through the area later tonight, touching
off chances for another round of light precipitation. Though clouds
continue to stream over the area this afternoon, water vapor imagery
and model soundings continue to indicate fairly limited midlevel
moisture. However, there is plenty of moisture apparent at lower
levels with warm air advection and increasing dewpoints leading to
additional snowmelt this afternoon. Heading into the evening and
overnight hours, advection fog becomes more common especially across
the eastern UP. Some locally dense fog is possible, with visibility
below a mile at times, before the cold front moves in and helps
scour out some of this lower level moisture.
As the aforementioned weak shortwave moves in, precipitation
currently over MN may initially struggle to reach the ground before
the midlevel dry layer apparent in soundings can erode somewhat.
However, it`s a quick hit, with drier air quickly working back in
behind the front which itself should largely be through the area by
12Z. So, there will be a limited window for any QPF at all with
trace amounts at most across much of the area. Precipitation type is
somewhat tricky. Across the eastern half of the UP, fairly deep
above-freezing thermal profiles (and wet bulb temperatures also above
freezing) suggest mainly rain. However, to the west, wet bulb
temperatures closer to freezing suggest a better chance for a change
over to a wintry mix with rain/snow/freezing rain by the early hours
of Friday. While snow/ice accumulations will likely be a trace at
best, some slick spots are still possible by the morning commute as
surface temperatures across the western UP fall to near/below
freezing with the passing cold front. This could lead to some re-
freezing of wet roadways as well.
.LONG TERM...(Friday night through Thursday)
Issued at 254 PM EST THU DEC 29 2022
Key messages:
-Dry Friday
-Next round of precip will be light snow showers Sat PM-Sun AM
-Next notable system looking to be late Mon-Wed
-Overall pattern thru January is moist but warmer
Once Thursday`s precipitation departs early Friday morning, the
remainder of Friday looks pretty dry. With the Upper Peninsula being
under the left entrance region of a jet, slight 500mb ridging
following trough passage, dry midlevels, and 850mb cold advection,
the sun should make a more prominent appearance than it has most of
December. Despite the cold advection, temperatures should remain
above freezing with diurnal heating from clearing skies and
subsidence warming. Mostly clear skies overnight will allow for
temperatures to cool to the dew point and with relatively light
winds, some fog could be observed, though capped to patchy in the
grids as there`s some uncertainty of the winds may be too high or if
the surface ends up being too dry.
Overnight Saturday into Sunday looks to be the next chance for
precipitation as a weak midlevel shortwave passes over the UP.
Despite ample moisture aloft, snow accumulations should be an inch
or less as forcing is not particularly well focused.
The next notable system is going to pass through the Upper Great
Lakes region starting late Monday to early Tuesday. EPS and GEFS
members are beginning to come into consensus that a 990s surface low
ahead of a 500mb trough will pass SW to NE in the vicinity of the
UP. Virtually all ensemble mean 2m temp anomalies at this time
indicate above average temperatures, so the path of the low is going
to be crucial to the precipitation type for the region. The 00Z EPS
pushes virtually all ensemble members south and east of MQT, which
would put most of the UP in the cold sector of the low. This allows
for an ensemble mean of around 4 inches of synoptic snow for
Marquette County, with some ensemble members at more than double
that, but an equal or greater number of ensemble members still under
2 inches. However, the 06Z GEFS tracks the system further north
along the MN Arrowhead, keeping the UP in the warm sector and a mix
of precipitation types preferred with a slight preference towards
all rain. The 12Z Canadian deterministic tracks the low right
through the heart of the UP, which would likely lead to a mix of
precip types that might favor more snow and wintry mix than rain.
This will require more monitoring as the storm approaches to get the
proper messaging out.
Overall, the pattern through January appears moist, but warm.
Frequent shortwaves in a troughing to zonal flow pattern will keep
arctic outbreaks from occurring but will provide forcing for
precipitation. Moisture wise, levels of the atmosphere supportive of
zonal flow will tap into moisture form the Pacific atmospheric
river, along with some Gulf of Mexico moisture at levels supportive
of southerly flow. In the shorter term, this is to blame for near
NAEFS climo-max PWAT for Monday and Tuesday, and in the longer term,
will keep PWAT anomalies generally high in the extended forecast.
&&
.AVIATION...(For the 00Z TAFS through 00Z Friday evening)
Issued at 631 PM EST THU DEC 29 2022
Light southerly flow ahead of an approaching cold front will result
in deteriorating ceilings and visibilities at all TAF sites.
Expecting trends toward IFR at KCMX and KIWD and LIFR at KSAW. KSAW
may end up reaching airport minimums at times until the cold front
swings through and winds shift westerly. A mix of light
snow/drizzle/freezing drizzle can`t be ruled out at KCMX/KIWD
overnight prior to the frontal passage, but confidence wasn`t high
enough to include in this TAF.
Cold front is expected to move west to east through the region by
morning, resulting in winds shifting westerly and improving ceilings
and visibilities at all sites. Current thinking is for KIWD and KCMX
to improve to MVFR and KSAW to VFR by early afternoon.
&&
.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 254 PM EST THU DEC 29 2022
Wind gusts remain below 20 knots on Lake Superior today until a cold
front passage late overnight and into Friday morning, when westerly
gusts pick up to 20-25 knots over the west half of the lake and 25-
30 knots over the east half, with the occasional gale force gust
possible. Winds fall below 20 knots Friday evening and remain that
way through the remainder of the forecast period. Next chance for
increased wind gusts will be with a passage of a surface low Tuesday
and Wednesday.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
None.
Lake Michigan...
None.
&&
$$
SHORT TERM...LC
LONG TERM...GS
AVIATION...JTP
MARINE...GS
Area Forecast Discussion
National Weather Service Norman OK
535 PM CST Thu Dec 29 2022
...New AVIATION...
.UPDATE...
Issued at 921 AM CST Thu Dec 29 2022
With a similar pattern to yesterday (southwest to westerly surface
flow, deep mixing), expect dewpoints to dip again across parts of
western Oklahoma and western north Texas. Used a mix of RAP and
NBM 10th percentile to lower dewpoints for the day. Thankfully
(in terms of fire weather), peak winds and minimum RH don`t have a
lot of overlap today (with winds starting to come down around
noon).
Day
&&
.SHORT TERM...
(This evening through Friday)
Issued at 334 PM CST Thu Dec 29 2022
Through Daybreak Friday: Owing to a continued downslope regime,
another afternoon of unseasonable late-December warmth is
occurring across the region (10-20 degrees above climatological
normals). At upper-levels, a shortwave trough continues to lift
towards the Corn Belt. An attendant cold front has advanced across
portions of north/northwest Oklahoma this afternoon. This feature
is expected to push southeastward through all zones by midnight.
Winds have remained gusty (30-40 mph) across western
Oklahoma/western-north Texas this afternoon, though are expected
to become lighter by early evening as the main upper system
departs the region.
Overnight lows are likely to run slightly above-average
(upper-20s across the north to low-40s far south). A few light
rain showers/sprinkles can`t be completely ruled out across the
far southeast CWA, though best chances for precipitation are
further east across the ArkLaTex region.
Friday: Relatively low-impact weather is expected to close out
the work week. Afternoon temperatures will once again run above-
average across the region (mid-50s to low-60s). Increasing cloud
cover and the chance for a few light showers will develop by the
evening across southern Oklahoma. At present, chances for
precipitation are low probability (<10%).
Ungar
&&
.LONG TERM...
(Friday night through next Wednesday)
Issued at 334 PM CST Thu Dec 29 2022
The Weekend: Low-impact weather continues to look likely for New
Year`s Eve/Day across the region, with warm and dry weather
expected. The upper pattern across the Southern Plains will be
characterized by shortwave ridging (centered at the Rockies). A
north-to-south gradient in temperatures (upper-50s to low-70s) is
expected across Oklahoma/north Texas, with warmest readings across
the Red River Valley.
Monday: This period looks rather active, with chances for
showers/storms across portions of the area. A high-amplitude/potent
shortwave trough is expected to move from the Four Corners through
the Plains during the day on Monday. Current expectations are for
showers and a few thunderstorms to develop along and ahead of an
eastward advancing cold front by Monday morning, generally along
and east of the I-44/I-35 corridors.
Owing to the potential for a marginally unstable and highly sheared
environment across the region, a few severe storms appear possible
on Monday. This is currently favored generally along and east of
the I-35 corridor. Indeed, ECMWF Extreme Forecast Index/Shift-of-
Tails Guidance points to unseasonable instability developing
across far east/southeast zones on Monday afternoon/evening.
Details regarding the character of the severe weather threat
(namely timing and possible hazards) will come into greater focus
over coming forecast cycles.
Uncertainties, especially regarding timing of the upper system,
remain at this update. The past few global (GFS/ECMWF) and
ensemble model cycles have displayed an overall slowing trend
regarding system timing across the western/central CONUS. In
addition, whether or not this system remains "in phase" or becomes
cutoff will determine timing/impact.
Middle of Next Week: A dip towards near-normal temperatures are
expected through the middle of next week. Precipitation chances
currently look low, though cluster/ensemble guidance hints at the
potential for an upper trough to follow closely behind the early
week system. Uncertainty in the upper pattern (and surface
impacts) increases by the middle to end of next week, though
current indications are for mostly dry times and seasonal
temperatures.
Ungar
&&
.AVIATION...
(00Z TAFS)
Issued at 532 PM CST Thu Dec 29 2022
Winds will shift to northerly across terminals this evening and
eventually back to southerly tomorrow. Winds expected to stay
light for the most part, although some brief gusts from the west
and northwest will be possible as front moves over north central
and central Oklahoma terminals this evening. Forecast will remain
VFR, although some patchy fog will be possible near KWWR and KPNC
around daybreak. Confidence too low for mention this far out.
&&
.PRELIMINARY POINT TEMPS/POPS...
Oklahoma City OK 36 54 38 61 / 0 0 0 0
Hobart OK 33 55 36 59 / 0 0 0 0
Wichita Falls TX 39 59 41 67 / 0 0 0 0
Gage OK 26 54 31 61 / 0 0 0 0
Ponca City OK 31 53 34 60 / 0 0 0 0
Durant OK 45 62 42 66 / 10 0 0 0
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...None.
TX...None.
&&
$$
SHORT TERM...34
LONG TERM....34
AVIATION...11