Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 01/30/23
Area Forecast Discussion
National Weather Service Gaylord MI
920 PM EST Sun Jan 29 2023
.UPDATE...
Issued at 911 PM EST Sun Jan 29 2023
Not much change to that which was inherited. Very disorganized and
light lake effect snow showers/flurries continue to rotate off the
northern Lake Michigan this evening. West flow has directed best
Lake Superior snows into areas north of the SOO. Approach of weak
shortwave trough and attendant uptick in low level
moisture/convective cloud depths will help organize lake snows
very late tonight into Monday morning. Most aggressive moisture
remains across Lake Superior, and with slowly backing flow, expect
organized and locally intense snow showers to impact northwest
Chippewa County toward morning. Local convergence from lake
aggregate troughing will only help the cause, and continue to
expect at least a few inches by sunrise up by Paradise and
Whitefish Point. Both convective cloud depths and synoptic
moisture contribution a bit less impressive across northern Lake
Michigan (no Lake Superior contribution either). Snow showers
will increase across northwest lower Michigan, but just looking at
minor snow accumulations...mostly under an inch.
&&
.NEAR TERM...(Through Tonight)
Issued at 212 PM EST Sun Jan 29 2023
High Impact Weather Potential: Lake effect snow showers will become
more numerous in west/northwest flow areas in northern lower tonight
and far northwest parts of Chippewa County in eastern upper. This
will result in areas of reduced visibility and snow covered roads.
Pattern Synopsis/Forecast: The current weather map features a
sprawling 1040mb arctic high pressure area centered over the
northern Plains with broad upper troughing and several embedded
shortwaves across the Great Lakes. Over northern lower Michigan,
relatively weak and disorganized wind fields through this evening
with winds gradually backing more westerly in advance of a surface
trough. This feature will slide through overnight with winds
organizing into a prevailing west/northwest boundary layer flow
after midnight as increasing amounts of low/mid level moisture
overspread the area. RAP forecast soundings show inversion heights
rising toward 5k with overlake instability increasing, with low
level theta-e lapse rates approaching 7 degc/km with lake induced
CAPES around 300 joules/km. Weaker lake effect activity through the
evening hours will blossom in coverage and intensity after midnight
in west/northwest flow areas as the activity pushes inland toward
the I-75 corridor. Generally light accumulations through Monday
morning, with a fluffy 1-2" possible in favored areas.
Over eastern upper, an impressive low level convergence axis
associated with lake aggregate troughing will strengthen this
evening before drifting slowly south toward northwest parts of
Chippewa County overnight. Lighter LES around Whitefish
Point/Paradise should ramp up after midnight with heavier,
accumulating snow possible. The DGZ will be in the lower portion
of the lake induced boundary layer but still supportive of
relatively high snow to liquid ratios (~20:1). A fluffy 2-4" of
snow will be possible in far northwest Chippewa County through 12z
Monday with accumulating LES continuing in this area on Monday.
With the expectation for several more inches of snow in this area
through Monday, have issued a winter weather advisory for western
Chippewa County through 06z Tuesday.
Low temperatures in the single digits and teens tonight with some
below zero wind chills possible - especially eastern upper.
Primary Forecast Concerns/Challenges: Given the high SLR`s with the
snow over northwest Chippewa County and the enhancement along the
convergence axis, always the possibility of surprising higher snow
totals in localized areas. Also concerned about lake enhancement off
of Little Traverse Bay later tonight with westerly flow, which could
boost snow totals in points to the immediate east of the bay.
&&
.SHORT TERM...(Monday through Wednesday)
Issued at 212 PM EST Sun Jan 29 2023
High Impact Weather Potential: moderate for the Whitefish Point
area... low elsewhere
Pattern Synopsis: extensive longwave troughing remains locked into
place across much of North America, supplying ample cold air across
the northern CONUS. Weak but pivotal shortwaves will pass through
along the main flow, which will keep the general idea of
troughing prolonged across the Great Lakes, all the while
reinforcing atmospheric profiles with modest moisture, which will
be enough to give a little bit of a jolt to the potential for lake
effect driven snows across northern lower and eastern upper
Michigan on both Monday and again Tuesday night.
Primary Forecast Concerns: significant accumulation potential north
of Paradise in Chippewa County on Monday... WNW flow accums expected
across northern lower Monday into Monday afternoon. Additional lake
effect possible late Tuesday into Tuesday night.
Eastern Upper- Variable winds are expected across the waters owing
to the lake aggregate troughing over eastern Lake Superior. Cold
air will be relatively deep and moisture will not be lacking
across the area. The big limiting factor for eastern upper will be
the spatial coverage of any lake effect snowfall. As of now, the
primary area of concern will be the development of significant
snowfalls across the Whitefish Point vicinity. Soundings suggest
high ratio snowfall for the area along and north of Paradise will
be ongoing Monday morning and continuing through much of the day.
Owing to the quick accumulation potential, it is possible for this
small area of Chippewa County to rack up a solid foot or more of
total snowfall through Monday night if persistent banding can move
inland. A limiting factor on how much snow falls will be that the
DGZ will be in the lower levels of the atmospheric profiles...and
if moisture in the very low levels of the profile is lacking,
this could lead to littler aggregates and therefore less efficient
snowfalls, despite snow ratios potentially as high as 20-25 to 1.
Farther east towards the Sault, the advection of any
mesolow could bring in the potential for accumulating snow
eastward, but largely north of M-28. Pending on how well any
mesolows hold up, there may be a brief window of heavier lake
effect snow in the Sault itself, but given that any snows will be
of a general short duration, the ceiling for snow accumulations
in the Sault Monday and into Monday night is a general 1 to
locally 4"+ of accumulation.
Northern Lower- We start Monday off with ongoing lake effect snows
across the area. Atmospheric profiles in NW lower show a WNW sfc
flow with steep lapse rates, and ample moisture in the low levels,
supporting the continuation of lake effect snows through the morning
commute. There are some hints that the moisture profile will become
deeper in the morning into the early afternoon, which may lead to an
uptick in snow across the region, but this will be a very short-
lived period. The trough axis swings through some time around or
just after 18z, and this will do quite a number on the moisture
profile as subsidence erodes low level moisture. This will result in
the weakening of any organized lake effect and synoptic snows in the
afternoon, largely leaving NW lower with some residual cellular
lake effect snow showers into Monday night. As of now, the best
accumulations are looking to favor the NW lower, with maxima`s of
2- 4"+ expected to favor the Antrim/Otsego/Kalkaska area, along
with locales downwind of Little Traverse Bay, which remains
unusually ice free for this time of year. Most other spots will
largely see a general inch or less of snow Monday. A break in the
action is looking likely across much of northern lower Monday
night into Tuesday as winds turn more W to WSW.
On Tuesday, much of the day will be dry across a majority of the
CWA, with perhaps the exception of some continued lake effect
activity across Whitefish Point. High pressure may even allow for
some peeks of sunshine to build across the region, but don`t let
that sunshine fool you because on the heels of the trough axis, a
potent shot of cold air will be keeping temperatures quite chilly.
Wind chills Tuesday morning will range anywhere from teens below to
twenties below. Air temperatures will generally be in the low
teens across much of the CWA on Tuesday, with wind chills perhaps
barely breaking above zero during the day. Another shortwave
intrudes on Tuesday night, which will bring the return of
favorable lake effect snow profiles, with the potential for
additional accumulations in WSW flow belts across northern lower
and eastern upper.
.LONG TERM...(Wednesday night through Sunday)
Issued at 212 PM EST Sun Jan 29 2023
High Impact Weather Potential...low for now...continued lake effect,
likely even colder later in the week.
The cold and modestly snowy pattern continues across the CWA, with
extensive troughing still encompassing the Great Lakes, with the
most likely outcome being continued quick hitting shortwave
action just after midweek. A digging trough across the far SW
CONUS will lead to a ridging response across the eastern US, but
this response will not be enough to dislodge the cold airmass we
have in place. There are also signs that a sharply colder airmass
will invade the northeastern United States later in the week and
into next weekend courtesy of a visit from the polar vortex, which
will likely center itself over Quebec and Atlantic Canada. This
will keep the cold airmass over us, with a resultant arctic front
likely keeping the influence of southerly flow out of the region,
and more of a progressive NW flow, which would favor more of a
clipper and lake effect pattern, though it`s a little too soon to
say whether this will be a prolonged and heavier period of lake
effect snows, because split flow may continue to wreak havoc on
available synoptic moisture for any prolonged lake effect
instability profiles.
&&
.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 640 PM EST Sun Jan 29 2023
Expecting mostly VFR conditions tonight, with increasing lake
processes Monday morning likely bringing more MVFR conditions with
periods of light snow showers. Expecting just minor snow
accumulations. Winds become a bit gusty out of the west on Monday.
&&
.MARINE...
Issued at 212 PM EST Sun Jan 29 2023
Significantly colder air will overspread the northern Great
Lakes this upcoming week with lake effect snow showers possible at
times. Marine headlines will likely be needed at various times with
periods of gusty winds. Given the very cold air, periods of gusty
winds may also bring freezing spray concerns.
&&
.APX WATCHES/WARNINGS/ADVISORIES...
MI...Winter Weather Advisory from 1 AM Monday to 1 AM EST Tuesday for
MIZ086.
LH...Small Craft Advisory from 10 AM Monday to 1 AM EST Tuesday for
LHZ347-348.
LM...Small Craft Advisory from 6 AM Monday to 1 AM EST Tuesday for
LMZ342-344>346.
LS...Small Craft Advisory from 6 AM Monday to 1 AM EST Tuesday for
LSZ321-322.
&&
$$
UPDATE...MSB
NEAR TERM...JK
SHORT TERM...HAD
LONG TERM...HAD
AVIATION...MSB
MARINE...JK
Area Forecast Discussion
National Weather Service Jacksonville FL
937 PM EST Sun Jan 29 2023
...New UPDATE...
.UPDATE...
Issued at 916 PM EST Sun Jan 29 2023
Forecast is on track as showers overspread much of SE GA with
a thunderstorm or two possible that could produce a brief
isolated wind gust 30-40 mph or small hail, but not expecting
severe thunderstorms. The showers will allow for god rain totals
of 1-2 inches from about Alma north and west. Otherwise SE GA
will be cloudy and cooler in the 50s compared to drier and a
little warmer over much of NE FL areas in the low 60s.
Rain showers will end by early afternoon over SE GA, exiting into
the Atlantic as the warm front weakens with a cold front stalling
just NW of the area. Enough surface instability and sufficient
shear, however, are available for an isolated strong storm, but
lack of surface lift from the warm front as it weakens may prevent
this possibility. Light southwest winds 10-15 mph expected with
highs reaching into the low 80s over NE FL and the upper 70s over
most of SE GA.
&&
.SHORT TERM...
(Monday through Tuesday night)
Issued at 405 PM EST Sun Jan 29 2023
On Monday, as the frontal wave moves east-northeast of the area,
a weak trailing cold front will slowly move across southeast GA
prompting a chance of showers and a few thunderstorms with best
chances from I-10 northward. The airmass will be plenty moist with
PWAT of 1.5 inches along the front, and instabilty is sufficiently
high for a strong storm or two mainly across southeast GA. HRRR
suggests instabilty of at least 1200 J/kg of MLCAPE amid bulk
shear values of 50-60 kt. The only negative for further severe
storm potential is weak forcing aloft. Still, there is a threat
for a couple of strong storms and will need to be monitored. Max
temps will be above normal. Monday night, the front stalls and
then slowly moves back north as as a warm front. Some lingering
weak convection still possible over north zones in the evening.
The pressure gradient remains weak and the low level flow will
encourage low stratus and fog overnight so we kept fog in the
forecast. Some dense fog is to be expected, mainly inland. Moist
low levels and clouds will keep min temps above normal.
Tuesday, after fog and stratus dissipate through the morning, a
weak boundary may remain near the Altamaha River basin. This will
support some slight chances of showers again over southeast GA.
Otherwise, partly to mostly cloudy skies with highs well above
normal, with lower 80s possible for northeast FL. Tuesday night, a
weak boundary is diffuse over parts of south central GA but the
main challenge will be development of fog and stratus again with
the weak pressure gradient in place. For now, just patchy to
areas of fog was advertised, but again at least some locally
dense fog is likely to form. Min temps above normal in the upper
50s to near 60.
&&
.LONG TERM...
(Wednesday through next Sunday)
Issued at 405 PM EST Sun Jan 29 2023
Wed-Thu, any quasi-stationary frontal boundary and enhanced moisture
over the north zones looks rather weak and diffuse ahead of the
next storm system approaching from the west. As such, any low rain
chances will be located over southeast GA. There will be potential
for some foggy mornings Wed and Thu mornings again due to the
light winds and some dry air aloft. As we move into late Thu into
Friday, a vigorous mid and upper level trough will move across
southern U.S. and moves into the southeast states by Friday night.
An associated sfc low pressure system will move across the area
late Thursday night into Friday. The low pressure system is
expected to push east or southeast of the area Friday night, with
the trailing cold front moving south of the area. Elevated chance
of showers and thunderstorms expected Thursday night through
Friday. Based on GFS and GFS ensemble guidance, there is a chance
of some strong to severe storms Thursday night into Friday with
the cold front. Lesser rain chances Sat and certainly Sunday as
strong high pressure is north of the area while low pressure will
be over the western Atlantic. Strong onshore flow is expected Sat
and Sun with beach hazards likely in play, with a low rain chance
at the coast as well.
Temps will continue above normal Wed-Thu, and begin to cool down
Fri due to the cold front moving in. Temps expected to be below
normal over the weekend in the wake of the strong cold front.
&&
.AVIATION...
(00Z TAFS)
Issued at 659 PM EST Sun Jan 29 2023
Cloud decks generally 4.0-5.0 kft to begin the 00Z TAF period and
should remain above 3.0 kft over the first 6 hours of the TAF period
as a warm front stretches near SSI WSW into the Fl panhandle.
Ceilings may lower tonight to low end MVFR at most TAF sites with
a low confidence in IFR ceilings at SSI as rain showers move in.
Some prevailing MVFR to IFR fog also possible at VQQ/GNV/SSI
09Z through 12/13Z. Showers will concentrate towards SSI between
06-12Z and persist into Monday through around 17-18Z with mainly
VCSH coverage at the duval terminals overnight. Showers should
largely avoid GNV and SGJ tonight into Monday with light southerly
winds becoming southwesterly 5-10 knots into Monday afternoon as
showers exit into the Atlantic and a weak cold front remains to
the northwest. Any storms that may develop near SSI are too low
in coverage to include at this time, therefore only have VCSH afer
17Z.
&&
.MARINE...
Issued at 405 PM EST Sun Jan 29 2023
Southerly winds look to increase a bit tonight as a weak low
pressure forms to the north, with a marginal exercise caution
headline for the offshore waters. Winds will trend toward a
lighter flow later Monday into Wednesday and Thursday with a
relatively weaker pressure gradient in place with directions more
varied. Seas will generally be around 2-4 ft the next few days. A
strong cold front is expected to sweep across the region by late
Friday into Friday night, with a strong north-northeast wind
developing, and building seas. Winds and seas for the weekend look
like small craft advisory will be needed. WNA wave guidance was
quite elevated for the weekend, with seas of 15+ feet possible
offshore Sat and possibly Sunday. For now, capped seas to 12-15 ft
with uncertainty on the WNA wind/sea guidance.
&&
.HYDROLOGY...
Issued at 405 PM EST Sun Jan 29 2023
There are river flooding warnings now in effect for parts of the
Altamaha River at Charlotteville and Baxley, reaching minor flood
stage within 24 hrs. Rain tonight over southeast GA could reach
up to 1-2 inches, and with localized flooding possible in poor
drainage areas. WPC has highlighted a marginal risk of excessive
rainfall over southeast GA mainly northwest of Highway 84 through
Monday morning.
&&
.PRELIMINARY POINT TEMPS/POPS...
AMG 56 76 60 77 / 90 40 20 20
SSI 58 75 58 71 / 60 30 20 20
JAX 60 81 59 80 / 30 20 20 10
SGJ 62 81 60 77 / 20 20 10 10
GNV 61 82 59 81 / 20 10 10 10
OCF 60 83 60 83 / 10 10 10 0
&&
.JAX WATCHES/WARNINGS/ADVISORIES...
FL...None.
GA...None.
AM...None.
&&
$$
Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
844 PM CST Sun Jan 29 2023
.UPDATE...
Issued at 844 PM CST Sun Jan 29 2023
Going forecast appears to be in good shape this evening, and have
made no adjustments except to include a slight chance of flurries
a couple of hours earlier. Otherwise, forecast of flurries
developing area-wide and some light snow across roughly the
southeast half of the forecast area (and perhaps some patchy light
freezing drizzle mixed in far south) appears to be on track.
Cold front which moved through the area yesterday is now well
south of the area across the Ohio Valley while arctic high
pressure spreads across the northern and central Plains. North of
the cold front, the 925-700 mb baroclinic zone lingers across MO-
IL-IN and will be the focus for a low-amplitude wave which transit
the flow tonight into early Monday. The combined effects of this
wave (tracking northeast from eastern OK/TX into AR as noted in
current water vapor imagery), and increasing upper divergence in
the right entrance region of a strengthening upper level jet
streak over the western Great Lakes region will lead to increasing
ascent and frontogenetic forcing across area overnight. RAP
forecasts suggest low-mid level f-gen will be somewhat transient,
though with better focus across the southern parts of the forecast
area which is also coincident with better (but not stellar) low
level moisture as noted in a comparison of DVN and ILX 00Z RAOBs.
Not surprisingly, guidance remains in good agreement in forecast
of light measurable precip roughly south of a Peru-Chicago line
across the southeast half of our forecast area. This should
largely be in the form of light snow, though the slightly warmer
profiles along our LOT/ILX border (greater than -10C) could
support some patchy light freezing drizzle at times if not
saturated to a sufficient depth for ice nucleation, though light
snow is expected to be the prevailing p-type. QPF is rather light,
with 0.01-0.06 supporting less than an inch of snow accumulation.
Exception may be across northern Porter county, where weak lake
effect band may push amounts to around an inch.
Going forecast has this all well accounted for, and have only
sped up development of flurries a couple of hours to mid-evening
with light snow then expected to develop toward midnight and
persist overnight before moving off to the east during the pre-
dawn hours.
Ratzer
&&
.SHORT TERM...
Issued at 238 PM CST Sun Jan 29 2023
Through Monday night...
Key messages for the short term are:
* The likelihood of light snow / flurries between 10 PM and 5 AM,
mainly along and south of I-80; non-zero chance of brief
freezing drizzle south of the Kankakee River
* Colder air filtering into the area with Monday having highs in
the upper single digits north to teens Chicago metro and south
* Subzero temperatures for at least far northern and north central
Illinois Monday night, though some uncertainty on clouds which
will influence how low temperatures drop
Stratocumulus is fairly locked in over the area this Sunday
afternoon that in tandem with northerly winds has prevented
temperatures from rising much at all. While a surface cold front
is well south of the area near the Ohio River, elevated
baroclinicity at 850-600 mb remains overhead, tightest over the
southern CWA. A low amplitude wave will traverse this elevated
frontal zone tonight, aided by a right entrance region of a 135+
kt upper jet. While this wave is on the weaker side in terms of
amplitude and mass response, it will undulate this baroclinic zone
with an area of 850-600 mb warm advection and some transient
frontogenesis in smaller layers and saturated near negative EPV
(low stability). Forecast saturated depths are around 7,000 ft in
the far south. The lift is not all that strong, and the
isothermal layer is a little warmer than the DGZ, but overall the
saturation and the baroclinic zone point us to continue a higher
PoP/low QPF forecast with a higher chance of light snow or
flurries. High-resolution model guidance generally supports this
will a spattering of light QPF. The further north in the forecast
area the less likelihood of this, especially of any dusting,
which is more supported south of I-80. Well south of I-80 (Gibson
City IL to Rensselaer IN), the saturated temperatures in the
column are warmer with only near -7C on forecast soundings. Light
freezing drizzle is possible (~20-30%) in this area.
With temperatures well below freezing, any light snow for a couple
hours that does materialize would easily produce a dusting,
including on roads. Again this is more favored south of I-80. The
timing of the light precipitation looks to be late evening into
overnight, wrapping up 3-5 A.M. There would probably be a lag
effect into early Monday morning on any untreated roads that do
see a dusting or glaze. So will need to keep an eye on
observational trends. At this time in the metro, the chance of a
dusting is 10 percent north to 40 percent far south.
Otherwise for tonight, a narrow north-to-south axis of convergence
on Lake Michigan will likely bring occasional flurries or light
snow in far northwest Indiana beginning this evening. As for
temperatures, clouds will somewhat offset the drop from the
northerly winds and gradual cold advection. It`s possible lows are
a smidge cool even though leaned milder than the guidance mean.
For Monday, an uptick in northwest winds will re-enforce the cold
air with highs likely not to reach 20F anywhere in the CWA, and
might not reach 10 over the snow-covered areas of far northern and
north central Illinois. This will also be the location most
favored to lose the low clouds prior to sunset Monday evening as
drier air moves in ahead of a 1035 mb high pressure. There is
still a signal for transient higher clouds with the upper jet
remaining anchored above the region. Depending on how persistent
any clouds are, lows will have a decent potential to drop into
the -5F to -10F range over snow-covered, non-urban heat island
locations. Farther south and east, temperatures will not be as
cold, but again low confidence on sky cover means there is a
fairly large spread of possible minimum temperatures.
MTF
&&
.LONG TERM...
Issued at 210 PM CST Sun Jan 29 2023
Tuesday through Sunday...
After a relatively busy period of winter weather the past few days,
the long term forecast period looks comparatively quieter, though
notably colder at times, as a handful of high pressure centers
parade through the region throughout the week.
Tuesday will start off on a chilly note, which will lower the
ceilings for Tuesday`s highs, despite the expectation that we should
see more sunshine than clouds by the afternoon. Most areas will
likely see daytime temperatures top out in the teens, though
locations in northern Illinois where a deeper snowpack is present
may struggle to reach double digits, while locations where this
snowpack isn`t as deep or is non-existent will stand a better chance
to reach the 20s. Relatively light winds and mostly clear skies
should then facilitate a period of efficient radiational cooling
that will result in another chilly night Tuesday into Wednesday with
temperatures bottoming out in the single digits at most locations
within our CWA.
Warm air advection beginning Wednesday morning will aid temperatures
in returning to closer to normal for this time of year, though
slightly below normal readings are still favored Wednesday into
Thursday before a dry cold frontal passage on Thursday will open the
door for a colder Canadian air mass to settle into the region
Thursday night into Friday. Southerly return flow on the backside of
the associated ~1040 mb surface high should then permit milder
temperatures to return for the weekend.
Depending on the exact track this surface high takes on Friday, an
elongated northwesterly to northerly fetch may materialize for a
several hour long period over Lake Michigan sometime in the late
Thursday night to Friday night time frame. Given the favorably cold
air mass moving over what may still be a relatively mild lake
(current southern Lake Michigan water temperatures are in the low
30s, though they will likely drop some after our upcoming cold
spell), conditions should become favorable for the development of
lake effect snow, and plenty of EPS and GEFS ensemble members show
support for this despite a fairly dry antecedent atmospheric
column. Whether the lake effect activity ends up favoring western
Michigan or portions of our CWA (particularly our northwest
Indiana counties) remains to be seen, but there`s enough of an
ensemble QPF signal into our forecast area to warrant maintaining
slight chance PoPs over the dry forecast that the NBM came in
with, especially when considering that the NBM is notorious for
underdoing PoPs for lake effect precipitation. Aside from any
potential lake effect snow on Friday, the rest of the long term
forecast period looks to be devoid of any realistic precipitation
chances across our forecast area.
Ogorek
&&
.AVIATION...
For the 00Z TAFs...
525 PM...Forecast concerns include...
Chance of light snow tonight.
Mvfr cigs tonight.
A weak system will move across central IL and north central IN
tonight bringing a period of light snow with the terminals being
on the northern edge of this light snow area. Prevailing light
snow is likely south of the terminals and perhaps at GYY. Current
tempo mention seems to handle the potential well with perhaps only
flurries at RFD.
Mvfr cigs will continue this evening and possibly lift to low vfr
but may lower back to mvfr with the expected snow overnight.
Eventually the mvfr cigs will scattered out Monday morning with
mid clouds expected through the afternoon.
North/northwest winds to 10kts will continue tonight and increase
into the 10-15kt range Monday as directions turn more northwest.
Some gusts into the 15-20kt range are possible Monday but low
confidence regarding how prevailing these gusts may become. cms
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...None.
IN...None.
LM...Small Craft Advisory...IL nearshore waters until 9 PM Sunday.
Small Craft Advisory...IN nearshore waters until 3 AM Monday.
&&
$$
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Area Forecast Discussion
National Weather Service San Francisco Bay Area
510 PM PST Sun Jan 29 2023
.SYNOPSIS...Showers today with much colder temperatures arriving
tonight. Frost and freezing temperatures are likely away from the
coast and are even possible for some coastal areas through mid
week. Warming by late week with rain chances returning.
.DISCUSSION...as of 12:10 PM PST Sunday...
This afternoon into Tonight:
The axis of an upper level trough was dropping south through the
Cascades/Shasta region of NorCal this morning. An associated jet max
was located across the Bay Area with increasing differential
cyclonic vorticity advection from the north. This was resulting
enhanced divergence aloft and a low-level mass response. A mesoscale
low pressure area was analyzed to the northwest of Sacramento with
surface troughing extending from the North Bay southeast towards
Death Valley. Weak surface pressure falls were occurring across the
Bay Area as the surface trough axis sinks south with time. Despite
the rather dynamic nature of the incoming system Blended Total
Precipitable Water (PW) and upper air observations suggest rather
meager moisture is available through the column with PW values on
the order of 0.4-0.5 inches. This is consistent with the 0.39 inch
value observed via the 29.12z KOAK sounding. Very cold air aloft was
associated with the upper trough with 500 mb temperatures of -27 to -
30 degrees Celsius noted to our north. Freezing levels were also
lowering in association with the trough as noted by the difference
in the KOAK and KMFR soundings (3,412 and 2,026 feet respectively).
A consensus of the high resolution models suggest that the upper
trough will advance through the Bay Area and Central Coast today
while a mid to upper low closes off. This will escort the
aforementioned surface low pressure across area with a subsequent
increase in lift and minor instability this afternoon and evening.
This is noted in RAP model forecasts which suggest low-level lapse
rates increasing to around -7 degrees/Km by 20Z today (noon). Most
unstable CAPE values also increase to around 100 J/kg during this
time; albeit located offshore from the coast. However an ensemble
max from the HREF does suggest the possibility of lower-end CAPE
creeping onshore from the South Bay towards the Central Coast. So
while thunder appears unlikely this environment should be supportive
of convective showers this afternoon and evening. The most likely
impact from these showers is brief moderate rainfall, with HREF
ensemble max precipitation values on the order of 0.1-0.25 inches
(locally to 0.25+ inches) over a 6-hour period from the South Bay
towards the Santa Lucias. That is not to say that everyone will see
those amounts, but there is at least a localized potential if you
happen to be right under one of the stronger showers. One additional
impact is the potential for small hail given the aforementioned
steepening lapse rates, lowering freezing level, and forecast
composite reflectivities from the HRRR model which suggest some
potential for max reflectivities >40 dBZ from the South Bay to the
Central Coast between 18-02Z (10AM-06 PM) today. Snow showers are
also possible on the higher peaks later this afternoon and evening
with a focus on the Santa Lucia and southern Gabilan ranges.
Accumulations should be on the light side however given the light
amounts and transient nature of the showers.
Much colder air will arrive tonight with breezy offshore winds over
the North Bay. This setup adds complexity to the the low temperature
forecast as more wind/greater mixing could keep readings up a bit.
The most likely forecast outcome still suggests temperatures near or
just below freezing over portions of the North and East Bays, with
similar to slightly colder conditions for San Benito County, inland
Monterey County, and in the Santa Cruz Mountains. However there
remains some potential for warmer readings depending upon how long
the wind stays elevated. Regardless, it will be dangerously cold for
unsheltered and/or marginally sheltered populations. Therefore
Freeze Warnings continue for inland areas with Frost Advisories for
much of the the coast and bays. An important note is that even if
some locations are a bit warmer/don`t experience frost/freezing
conditions tonight, odds look even better for Monday night.
Otherwise look for clearing skies from north to south overnight with
showers departing.
Monday through Thursday:
High pressure will be in control at the surface and aloft. This will
result in quiet conditions and cold overnight low temperatures.
Freezing to sub-freezing conditions are possible for most areas
outside of the most protected locations along the Coast and Bays.
These conditions will be dangerous for those without adequate
shelter. Remember to protect people, pets, plants and pipes from the
cold. Temperatures will gradually moderate on Thursday ahead of the
next approaching weather system.
Friday through Sunday:
An upper trough will advance from the eastern Pacific through the
west coast early in the period bringing rain chances on Thursday
night into Friday. Another chance for showers may return later in
the weekend. At this point rain amounts appear light. Temperatures
should remain seasonal.
&&
.AVIATION...as of 05:10 PM PST Sunday...For the 00Z TAFs. Low
pressure over the area is bringing scattered light showers and a
mix of MVFR/VFR conditions. Showers are diminishing in coverage
and should end by around 02Z around SF Bay terminals, and a couple
of hours later for Monterey Bay, as the low pushes southward.
Winds are generally northerly with some gusts over 20 kt, but
otherwise moderate. Increasing NE winds aloft tonight may bring
some stronger gusts to North Bay terminals, and potential LLWS as
winds near 40 kt above 1000 ft. Otherwise, some breezy N/NE winds
around SF Bay overnight, with clearing skies and VFR conditions.
Lighter winds expected Monday afternoon with continuing VFR.
Vicinity of KSFO...Borderline VFR/MVFR cigs around the area with
showers diminishing in coverage, and ending by around 02z. Winds
northerly and breezy at KSFO, 15-20 kt. Could see breezy
conditions continuing overnight, but low confidence in wind
strength, as strongest winds will be focused over North Bay.
Skies clear out late tonight behind the departing low, with high
confidence in VFR persisting through the day Monday. Lighter winds
Monday with NE flow continuing.
KSFO Bridge Approach...Low clouds over the approach clearing after
06z.
Monterey Bay...Scattered showers continue through the evening with
prevailing VFR conditions, but periods of MVFR possible through
around 03z. Cigs lifting gradually overnight and scattering with
VFR expected through Monday as drier air moves in behind the low.
Lighter winds Monday turning onshore in the afternoon.
&&
.MARINE...as of 02:40 PM PST Sunday...Gusty northwesterly winds
and steep seas continue as cold front moves through the waters.
Wind gusts could briefly reach gale force strength north of Pigeon
Point through this morning. Winds shift northeasterly as surface
low moves through the Bay Area this evening. Light rain mainly
over the southern waters to continue tonight. A series of longer
period northwesterly swells will enter the waters this upcoming
week.
&&
.MTR WATCHES/WARNINGS/ADVISORIES...
.Tngt...Frost Advisory...CAZ502-503-505-508-509-516-517-528>530
Wind Advisory...CAZ504-506
Freeze Warning...CAZ504-506-510-512>515-518
SCA...SF Bay
SCA...Pt Arena to Pt Reyes 0-10 nm
SCA...Pt Reyes to Pigeon Pt 0-10 nm
SCA...Pigeon Pt to Pt Piedras Blancas 10-60 nm
GLW...Pt Arena to Pigeon Pt 10-60 nm until 9 PM
&&
$$
PUBLIC FORECAST: SPM
AVIATION: Lorber
MARINE: Behringer
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Area Forecast Discussion
National Weather Service Nashville TN
642 PM CST Sun Jan 29 2023
...New UPDATE...
.UPDATE...
Issued at 634 PM CST Sun Jan 29 2023
A slow-moving surface boundary will edge its way across Middle
Tennessee during the next several hours. This is providing the
focus for the ongoing showers that are affecting mainly southern
Middle Tennessee this evening. The HRRR shows widespread showers
spreading northward overnight, but will still affect mainly areas
south of I-40 and along the Cumberland Plateau. Tomorrow`s rain
chances are considerably lower as the surface boundary finally
pulls east of the mid state. The evening sounding from OHX shows a
saturated boundary layer, but relatively little moisture above
~900 mb. This is not surprising given that the deepest moisture
remains to our south. In addition to the overnight rain chances,
look for fog to develop across the greater portion of Middle
Tennessee. Dew point spreads have already shrunk to zero -- or
very close to zero -- at a number of our weather stations, so
even with the widespread cloud cover, look for significant areas
of fog.
&&
.SHORT TERM...
(This afternoon through Monday Night)
Issued at 229 PM CST Sun Jan 29 2023
Rain...rain...and more rain. The current rain event is coming to
an end however there will be more tonight and ending on Monday.
The dry period still looks like 18Z on Monday to 06Z on Tuesday
and then precipitation starts again. QPF totals through tomorrow
afternoon one half to one inch. Don/t expect any flooding
issues...just a good soaking rain at times. Temperatures tonight
ranging from mid 30s NW to mid 40s lower plateau. Highs tomorrow
under cloudy skies will be mid 40s NW to mid 50s plateau.
Precipitation moves back in Monday night and temperatures fall.
This is a start to a VERY tricky forecast! Monday night will see a
mix of precipitation for the northwest. Anything from rain to
freezing rain...to snow. Accumulations are not such that it will
reach advisory criteria...however that does not mean one won/t be
issued based on impacts. Will hold off for now.
&&
.LONG TERM...
(Tuesday through next Sunday)
Issued at 229 PM CST Sun Jan 29 2023
The good news on Tuesday fingers crossed is temperatures will warm
up enough to the middle to upper 30s for the northwest so
hopefully any non rain precipitation will melt and not cause many
if any impacts. Still concerns that there could be a wetbulb
effect and freezing drizzle could hang around. As said...very
challenging. Another impulse Tuesday night into Wednesday. This
one now looks to be the stronger and more pesky one. This spreads
ice further south and east...bring light accumulations /a
hundreths or so/ all the way down to I-40. Once again anything
that was frozen Tuesday night will melt on Wednesday as
temperatures warm into the 40s. Another impulse can be expected
on Thursday. The heaviest precipitation should be to the south.
There could be some frozen precipitation Thursday night. Still too
early to worry about this. So...after almost 6 days of
precipitation it looks like Saturday and Sunday will be dry! Cold
but dry...with highs 45 to 50. Rainfall totals from midnight
Tuesday through Friday right now range from a half inch NW to 2.5
inches south.
&&
.AVIATION...
(00Z TAFS)
Issued at 528 PM CST Sun Jan 29 2023
Mostly IFR/LIFR through the next 24 hours. A cold frontal zone
will move slowly across the area late tonight into Monday morning.
With a lot of low level moisture remaining in place, there will
be extensive low clouds, drizzle, and areas of fog. Winds will be
light, mainly ESE overnight, becoming NNW around 8KT after the
front passes Monday morning. IFR/LIFR with stratus, fog, and
drizzle will continue well after the frontal passage.
&&
.PRELIMINARY POINT TEMPS/POPS...
Nashville 44 51 32 40 / 50 20 50 50
Clarksville 38 43 27 36 / 30 20 50 40
Crossville 42 55 36 44 / 80 30 50 50
Columbia 45 53 31 40 / 70 20 50 50
Cookeville 46 54 35 41 / 60 30 50 50
Jamestown 42 53 33 41 / 50 30 50 50
Lawrenceburg 46 54 34 41 / 70 20 50 50
Murfreesboro 45 54 32 41 / 60 30 50 50
Waverly 39 46 27 36 / 50 20 60 40
&&
.OHX WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
UPDATE.......Rose
SHORT TERM...12
LONG TERM....12
AVIATION.....13
Area Forecast Discussion
National Weather Service Tallahassee FL
953 PM EST Sun Jan 29 2023
...New UPDATE, MARINE, HYDROLOGY...
.UPDATE...
Issued at 931 PM EST Sun Jan 29 2023
Surface analysis shows a nearly stationary front near or
immediately south of the Florida-Alabama state line. The front has
sharpened up over the last few hours and could serve as a focus
for heavy rain over the next couple hours. The 00z HRRR focuses
most of the remaining heavy rain from Apalachicola to Tifton,
with additional amounts around 2 inches or less through the early
overnight hours.
&&
.NEAR TERM...
(Through Monday)
Issued at 503 PM EST Sun Jan 29 2023
Surface low looks to be near the Arklatex region, with a warm front
slowly moving into the region. Scattered rain showers have popped up
as a result, with widespread rain being observed over AL this
afternoon. Expect the moistening trend to continue with scattered to
widespread rain expected late today and into tonight. The highest
rain amounts look to remain confined to our SW GA, SE AL, and the FL
Panhandle. 1 to 2 inches of rain is forecast for much of the area,
with the southern GA counties and eastern Panhandle counties having
totals closer to 0.5 to 1 inch. For the Big Bend, amounts have had a
slight trend downwards with with around 0 to 0.5 inches forecast,
driest in the southeastern counties. Poor drainage, nuisance, and
perhaps urban flooding may occur if rain or storms train in an area.
The severe weather risk remains low, but non zero. 18Z TAE sounding
shows no surface layer CAPE, with some MU CAPE around 227 and the
convective temperature at 81F. If severe weather were to occur the
best chances should be in the FL Panhandle, west of the Apalachicola
River, and perhaps in our southern most AL counties.
Rain comes to an end on Monday from south to north, with a cold
front trying to make its way towards us. It doesn`t look to hold up
very well, so we`ll be left with warm and moist conditions. This
should allow for fog to develop, perhaps as early as Monday morning
pending how the rain pans out. Eventually, sea fog looks to form and
then advect inland. Areas to wide spread fog are expected late
Monday into Tuesday.
&&
.SHORT TERM...
(Monday night through Tuesday night)
Issued at 503 PM EST Sun Jan 29 2023
Surface high pressure forms over the Carolinas and noeses west
towards the SE. This should keep conditions warm and dry through
Tuesday night. We might have a few pop up showers try and clip our
northern most CWA counties. Highs Tuesday will be in the in the mid
to upper 70s.
&&
.LONG TERM...
(Wednesday through Saturday)
Issued at 503 PM EST Sun Jan 29 2023
Through the long term the main event to look forward to appears to
be Thursday evening into Friday. As a long wave trough, currently
over California, moves east across the Rocky mountains it splits in
half with a shortwave forming on the leeward side of the mountains.
This "split" means the parent trough to the north outruns the
shortwave to the south. This is good for our region as that means
the Arctic air associated with a deep trough remains to the north,
away from our region. As this shortwave approaches the region
unsettled weather returns. With the possibility for CAPE around
500 J/kg, an LLJ around 40 - 60 kts and PWATs around 1 to 1.5
inches, the possibility for some marginal severe is possible.
However, given that this would once again be an overnight event,
convective inhibition may be a limiting factor. We`ll have to keep
an eye out for this event through the coming days for any new
developments. Otherwise, outside of Thursday and Friday, weather-
wise we may see some scattered showers on Wednesday given warm and
moist air in the region. Meanwhile Saturday is expected to be
quiet, cool and dry as the cold front has moved through.
Daytime highs will generally be in the 70s on Wednesday and Thursday
with a drop into the upper 50s to low 60s by Saturday once the cold
front is through. A similar trend is in store for the overnight low
temps with upper 50s and low 60s on Wednesday dropping into the low
40s by Saturday morning.
&&
.AVIATION...
(00Z TAFS)
Issued at 708 PM EST Sun Jan 29 2023
Widespread IFR/LIFR cigs are expected at all terminals after 00Z,
including reduced vsby. SHRA with embedded TSRA is expected to
continue throughout the overnight hours. Showers and storms begin
winding down throughout the late morning hours tomorrow. South to
southwesterly winds around 10 kts are expected through tomorrow
morning. Conditions begin to improve slightly by the end of the
TAF period, with cigs beginning to lift into MVFR heights.
&&
.MARINE...
Issued at 931 PM EST Sun Jan 29 2023
Moderate southerly breezes will diminish on Monday morning, in
advance of a cold front that dissipate late Monday just as it
enters the northeast Gulf. Muggy air and chilled nearshore shelf
waters will lead to some sea fog Monday night into Tuesday.
Another cold front will make a run towards the Gulf waters later
Tuesday and Tuesday night, but this feature too appears to stall
around the coast. Fog for Wednesday morning is more questionable
depending how far south the front can reach.
&&
.FIRE WEATHER...
Issued at 503 PM EST Sun Jan 29 2023
Wet weather is forecast for much of the area through tomorrow
morning, with wetting rain looking likely for SE AL, SW GA, and
most FL counties. Dispersions are expected to be low the rest of
today and into tomorrow morning. Areas along I-10 and into our
SE GA counties may creep above 20, with surrounding areas
staying below. Rain tapers tomorrow from south to north, with
drier weather forecast for Tuesday and Wednesday. A few showers
may pop up those days, otherwise moist and warm conditions
prevail with low dispersions on Tuesday. Wednesday dispersions
look to be low north of I-10 but may range from 20 to 30.
&&
.HYDROLOGY...
Issued at 931 PM EST Sun Jan 29 2023
2 to 4 inches of rain fell this evening over a large part of
southeast Alabama, generally northwest of a line from Geneva to
Dothan. The heaviest rain of 3 to 4 inches occurred in Coffee and
Dale Counties, including places like Elba, Enterprise, and Ozark.
Heavy rain of 1 to 2.5 inches has also been common across Henry,
Clay, Randolph and Terrell Counties, affecting headwaters of the
Kinchafoonee, Muckalee, and Ichawaynochaway basins. Looking out
overnight, a swath of 1 to 3 inches of rain is expected from
Apalachicola to Tifton.
Rivers in the affected basins will rise and run high over the next
few days, in some cases cresting just below flood stage. At this
time, no rivers are explicitly forecast to reach flood, but it
could be a close call in basins like the Pea-Choctawhatchee.
Rivers with headwaters in Georgia will run high this week.
&&
.PRELIMINARY POINT TEMPS/POPS...
Tallahassee 61 78 63 76 / 70 30 0 10
Panama City 62 74 62 72 / 60 20 0 10
Dothan 58 74 60 74 / 90 30 10 10
Albany 57 74 60 74 / 90 40 10 10
Valdosta 59 78 63 78 / 60 30 0 10
Cross City 58 78 60 80 / 20 10 0 0
Apalachicola 63 72 62 70 / 60 20 0 10
&&
.TAE WATCHES/WARNINGS/ADVISORIES...
FL...High Rip Current Risk through Monday afternoon for FLZ108-112-
114-115.
GA...None.
AL...None.
GM...None.
&&
$$
NEAR TERM...KR
SHORT TERM...KR
LONG TERM....Oliver
AVIATION...Oliver
MARINE...Haner
FIRE WEATHER...KR
HYDROLOGY...Haner