Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 12/04/18
Area Forecast Discussion
National Weather Service Grand Rapids MI
628 PM EST Mon Dec 3 2018
LATEST UPDATE...
Aviation
.SYNOPSIS...
Issued at 251 PM EST Mon Dec 3 2018
Fairly quiet weather this week with cold temperatures and only
light snow chances for Wednesday through Friday.
&&
.DISCUSSION...(This evening through next Monday)
Issued at 251 PM EST Mon Dec 3 2018
Fair weather overnight then some snow showers possible across the
western zones on Tuesday as northerly flow tonight becomes
northwest then west. Inversion heights are around 5 kft and this
will keep any accums light.
Lake enhanced snow showers get a boost on Thursday with clipper
and arctic front providing low level convergence as inversion
heights come up a bit. Expect an inch or two with this event and
possibly another inch or two over the course of westerly flow
lake effect snow showers Thursday night and Saturday.&&
.AVIATION...(For the 18Z TAFS through 18Z Tuesday afternoon)
Issued at 1252 PM EST Mon Dec 3 2018
Ceilings will be in the 1500 to 2500 foot AGL level this
afternoon with tops above 5000 feet decreasing to about 3000 feet
by late afternoon. VFR conditions are expected this evening and
into Tuesday. Lake effect snow showers should remain over Lake
Michigan in northerly wind regime.
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 629 PM EST Mon Dec 3 2018
For the most part expect MVFR cigs through Tuesday night. Also
expect in cloud light to moderate rime icing between 2500ft agl
and about 6000 ft agl. during this time period.
It should be noted however I do expect a short period of clearing
late tonight into the mid morning hours of Tuesday thanks to the
prevailing north wind bringing down drier air from the north. Even
as I write this the clearing line is moving south into northern
Lower Michigan from eastern Upper Michigan. This clearing is shown
in both the NAM and RAP models in the 09z to 15z time frame. The
RAP model is stronger in the clearing and if that turns out to be
correct the clearing may last most of the day for the TAF sites
east of Grand Rapids.
&&
.MARINE...
Issued at 251 PM EST Mon Dec 3 2018
No changes to the Small Craft Advisory.
&&
.HYDROLOGY...
Issued at 1252 PM EST Mon Dec 3 2018
Water levels in the larger rivers and streams continue to rise in
response to rain and snowmelt over the weekend. Rivers and streams
in the eastern portion of the Grand River Basin will rise to
bankfull or near-bankfull through the end of the week, but will not
reach flood stage.
Precipitation through the rest of the week will be in the form of
occasional light snow and will not have any impact on river levels.
Temperatures will be below freezing through most of the next seven
days. While ice may form on some creeks and streams, freeze-up ice
jams are not anticipated.
&&
.GRR WATCHES/WARNINGS/ADVISORIES...
MI...None.
LM...Small Craft Advisory until 3 AM EST Tuesday for LMZ844>849.
&&
$$
SYNOPSIS...Ostuno
DISCUSSION...Ostuno
AVIATION...WDM
HYDROLOGY...HLO
MARINE...Ostuno
AREA FORECAST DISCUSSION...UPDATED
National Weather Service Jackson KY
1101 PM EST Mon Dec 3 2018
.UPDATE...
Issued at 1101 PM EST MON DEC 3 2018
Isolated to scattered showers, likely falling as snow above about
2000 feet, and rain or a rain and snow mix elsewhere continue
across the area. Based on regional observations from the KY
Mesonet, AWOS, and KYTC stations, temperatures remain above
freezing below 2500 feet. With this and upstream temperatures
mainly in the low to mid 30s, it appears that valleys across
southeastern portions of the area will probably not quite reach
the freezing mark overnight. Isolated to scattered upslope/instability
snow showers are anticipated at times overnight.
UPDATE Issued at 725 PM EST MON DEC 3 2018
An area of showers continues to move across East KY this evening.
This has mostly fallen as rain with surface wetbulb temperatures
generally above freezing, around the mid 30s. The highest terrain
has cooled off sufficiently enough that this precipitation will
fall as snow on top of Black and Pine Mountains. Even there,
temperatures are not below freezing below 3000 feet. Hourly pops
and temperatures were adjusted to account for recent radar and
observation trends. Overall, no substantial changes were needed
at this time.
&&
.SHORT TERM...(This evening through Tuesday night)
Issued at 345 PM EST MON DEC 3 2018
20z sfc analysis shows a large area of low pressure off to the
northeast of Kentucky with cyclonic flow through the Ohio Valley.
This flow continues to bring in lower level clouds over eastern
Kentucky and points northwest. This, along with some cold air
advection on westerly winds at 5 to 10 mph (with occasional higher
gusts), has lowered temperatures through much of the afternoon.
Readings now vary from the upper 30s northwest to the mid 40s in
the far southeast or several degrees down from noon readings most
places. Dewpoints, meanwhile are generally running in the lower
30s. Some light returns are showing up on radar with reports of
light rain reaching the ground north, though some flurries could
be mixing in as the boundary layer temperatures are falling
through the upper 30s in the northwest parts of the area.
The models are in good agreement aloft through the short term
portion of the forecast. They all depict some weak waves running
along the base of a large trough through the heart of North
America in nearly zonal flow. The first of these pass through
this evening with another stronger one due in here later Tuesday
through Wednesday morning. The model agreement raises confidence
for the weather details through Wednesday morning even as it falls
later in the forecast with widening model spread. Through the
short term have favored a general model blend with a strong lean
toward the higher resolution near term models like the HRRR and
NAM12 for details.
Sensible weather will feature a chilly couple of days as clouds
and a cooler air mass have settled over the area. With this,
there will be periodic bouts of light pcpn mainly in the form of
light rain/sprinkles this evening and snow showers/flurries later
tonight through Wednesday morning. Given the warm ground and road
temperatures any snow shower activity through the day Tuesday
will not accumulate except perhaps a thin layer on elevated or
grassy surfaces. A better chance for some light snow to stick to
the ground will be Tuesday night into Wednesday morning when up
to an inch could occur on the ridges in the east with lesser
amounts seen elsewhere. Temperatures will not exhibit much of a
diurnal range during this time with highs only in the the mid 30s
most places Tuesday but lows that night down to the mid and upper
20s. The accumulating snow chances late in the period will be
highlighted in the HWO along with a forthcoming partner email
addressing the winter weather threat through Wednesday morning.
Used the ShortBlend and CONSShort again as the starting point of
the grids, though did tweak some point temperatures for very minor
terrain aspects both nights. As for PoPs: adjusted them slightly
per the near term guidance for better snow chances, especially
Tuesday night.
.LONG TERM...(Wednesday through Monday)
Issued at 305 PM EST MON DEC 3 2018
The forecast issues in the extended will center around the
potential for wintry precipitation at different time through out
the period. Initially, we can expect isolated to scattered snow
showers across the area on Wednesday, as moist westerly flow
behind a departing area of low pressure interacts with the terrain
of eastern Kentucky. Snow fall amounts during this time should be
very light, but it will remain to be scene whether or not any
impacts will result from this initial snowfall. After a dry period
Wednesday night through Thursday morning, another round of rain
and snow is expected. This second round of precipitation is a bit
more uncertain, as the latest model runs are having a difficult
time producing much in the way of moisture across the region.
Based on that, decided to decrease precipitation chances for the
time frame from Thursday afternoon through Friday morning. Another
brief lull in the action is expected for most of the day on
Friday. The biggest player in the extended period will be a
weather system that is forecast form somewhere along the western
Gulf coast Friday night into Saturday morning. The forecast are
very different from one another regarding the exact track and
timing of this third weather system. One model is taking the low
track along the Gulf Coast, which would keep precipitation
associated with the system well south of eastern Kentucky. Another
model has the system tracking a bit further north, but still far
enough south to keep most are all precip outside of our area. Two
other weather forecast models have the system tracking far enough
north to bring rain and then decent snowfall into eastern Kentucky
Saturday into Sunday. The issue here is that each of these models
have different timing with precip onset and evolution of the
system as it moves off to the east. At this time, with all the
uncertainty involved, the blended model data was used to create
the forecast for the extended. The trend in the blended data was
for lower precipitation chances across the area, likely due to the
uncertainty contained in the individual models. In general, the
best chance for precipitation should be for the weekend. Snowfall
amounts should be taken with a grain of salt until the individual
models come into better agreement.
Temperatures during the extended look to be well below normal, with
daily highs forecast to max out generally in the 30s to mid 40s, and
nightly lows in the low to mid 20s.
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
ISSUED AT 720 PM EST MON DEC 3 2018
A cloud deck with mainly VFR currently reported across East KY
with some patches of MVFR. With continued cooling and saturation
of the atmosphere closer to the surface, ceilings should gradually
decrease into the MVFR range in all locations over the first 6 to
9 hours of the period. MVFR should persist through at least 18Z
all locations, though some patchy VFR is possible late in the
period. West to northwest winds of 5 to 10 kts ushering in colder
air initial isolated to scattered rain or snow showers are
expected with any remaining precipitation mainly isolated to
possibly scattered snow showers after 6Z.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...JP
SHORT TERM...GREIF
LONG TERM...AR
AVIATION...JP
Area Forecast Discussion...UPDATED
National Weather Service Lubbock TX
950 PM CST Mon Dec 3 2018
.UPDATE...
Minor update to add the mention of fog across the
southwest/south-central Texas Panhandle into the northern South
Plains late this evening, expanding to all areas on the Caprock
after midnight. Temperatures have cooled efficiently this evening
and were now approaching the dewpoint across the northwestern
zones. Hereford was already reporting light visibility reductions,
and the webcam at Silverton was showing a hazy view...perhaps the
precursor of thicker fog to come. The HRRR and RAP are now
suggesting at least patchy fog (locally dense) will form over
parts of the Caprock through the night as the weak, cool and moist
upslope flow continues. Winds will veer toward morning, and this
could limit the extent of the fog. Any fog should lift/scatter by
mid-morning Tuesday. No other adjustments were made to the
forecast at this point.
&&
.PREV DISCUSSION... /issued 602 PM CST Mon Dec 3 2018/
AVIATION...
VFR has returned to all three TAF sites and should persist this
evening. It becomes less clear late tonight into Tuesday morning
as cool and relatively moist conditions linger. Our guidance
varies greatly, showing anything from VFR to IFR developing at
all three TAF sites. Thus, confidence in outcome and timing is
low, but have continued to reflect MVFR conditions at the
terminals late tonight, lifting to VFR Tuesday afternoon. Winds
will be light through the period.
PREV DISCUSSION... /issued 424 PM CST Mon Dec 3 2018/
DISCUSSION...
Surface high pressure currently centered over the north Central
Plains and northwest flow aloft will continue the cooler than
normal temperatures through mid-week. The cooler temperatures
will persist out ahead of a developing upper level, closed low
that will bring rain on Thursday and a wintry mix of precipitation
on Friday into Saturday.
The Pacific low will shave the coast of California over the next
couple of days and then evolve into an open wave, becoming more
progressive as the southern jet becomes more active. Rain on
Thursday should mostly be relegated to the southern half of the
South Plains and Rolling Plains ahead of a surging cold front. The
front will move south out of the Texas Panhandle during the day
Thursday, with a moisture gradient that extends from central Texas
westward along the I20 corridor.
As the surface low begins to deepen late Thursday night while it
moves out of West Texas over central Texas, colder air from the
aforementioned surface front will be reinforced on the back side
of the exiting low. A wintry mix may begin to develop overnight
Thursday into Friday across our northern zones before sunrise.
Current vertical profiles hint at some freezing rain overnight,
but its too soon to have confidence in that outcome. From that
point on there remains quite a bit of uncertainty with regard to
precipitation phase through the day on Friday. Best chances for
wintry precipitation during the day Friday will be across the
southern Texas Panhandle with more of a mix of rain/sleet/snow
possible over the South Plains and Rolling Plains. Whatever
moisture remains into late Friday and early Saturday should result
in light snowfall. Overall, impacts should be minimal, though
travelling across our forecast area during the day on Friday may
get increasingly more difficult the farther north you go. We dry
out quickly on Sunday with temperatures returning to the mid 40s
as an amplified ridge builds over the west.
&&
.LUB WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
23/99
Area Forecast Discussion
National Weather Service Marquette MI
536 PM EST Mon Dec 3 2018
.SHORT TERM...(This evening through Tuesday)
Issued at 335 PM EST MON DEC 3 2018
WV imagery and RAP analysis indicated mid/upper level ridging
from the northern plains and upper Mississippi valley building
into the northern Great Lakes. At the surface, high pressure was
also building into the area with increasingly anticyclonic nw to n
flow. With subsidence and drier air moving in from the north,
some holes have developed over the cloud deck with clearing on
upstream shores of Lake Superior. With 850 mb temps only to around
-9C and relatively shallow moisture, any flurries or freezing
drizzle has ended.
Tonight, winds will back west-northwest tonight as the high pressure
ridge moves across the area. The backing winds will focus any LES
that develops over the nw and from Marquette eastward as partial
clearing will be possible over central and southern portions of
Upper Michigan. Some fzdz may still be possible with only marginal
temp/moisture profile for ice nuclei availability. However, given
the amount of low level drying, expect little potential for any
significant glaze.
Tuesday, winds will back to w or wnw limiting light LES/flurries to
the Keweenaw and locations north of M28 over the east. The low level
west winds will favor at least partial clearing over the rest of the
area. Highs will remain in the mid to upper 20s.
.LONG TERM...(Tuesday night through Monday)
Issued at 324 PM EST MON DEC 3 2018
Tranquil through midweek followed by a brief uptick in northwest
wind lake effect with a return to quiet seasonable weather over the
weekend.
Mean upper troughing will remain over the eastern U.S. into the
weekend. A clipper system and associated cold front will usher a
brief surge of below normal temperatures into the Upper Lakes for
Thursday and Friday. The arrival of this colder airmass with 85H
temperatures lowering to -20C will briefly spike lake EL levels up
close to 10kft late Wednesday night into early Thursday. This will
be the time period for a burst of moderate snow for northwest wind
favored areas with a few inches of accumulation.
Prior to the arrival of this front 85H temperatures will be marginal
for some light westerly wind lake effect across the Keweenaw on
Wednesday. Accumulations will be very light.
Inversion heights begin to lower significantly by later Thursday
into Friday. 85H temperatures will support continuation of
northwesterly wind lake effect, but amounts will remain in check.
By Saturday...upper heights begin to rise across the Plains with
west northwesterly wind warm advection bringing an end to the lake
effect. Temperatures will modify back to normal with dry weather for
the weekend into early next week.
Push of mild Pacific air in a more zonal pattern will result in a
mild middle part of December with above average temperatures and
limited significant storm chances.
&&
.AVIATION...(For the 00Z TAFS through 00Z Tuesday evening)
Issued at 536 PM EST MON DEC 3 2018
Low end MVFR Cigs will persist through tonight with low level
moisture lingering below a strengthening inversion. Marginal
improvement is expected at KSAW with climbing CIGS that may scatter
out by Tuesday afternoon as drier air moves in with winds backing
wrly.
&&
.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 335 PM EST MON DEC 3 2018
As the pressure gradient continues to weaken north winds will
diminish to 20 knots or less tonight into Tuesday morning. while
backing west-northwest. Tuesday afternoon into Wednesday westerly
winds will increase slightly to 15 to 25 knots. Next chance for
stronger northerly winds will arrive late Wed night into Thursday
behind a stronger cold front when northwest to north gale force
gusts are possible
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
None.
Lake Michigan...
None.
&&
$$
SHORT TERM...JLB
LONG TERM...MZ
AVIATION...07
MARINE...JLB
Area Forecast Discussion
National Weather Service Tallahassee FL
843 PM EST Mon Dec 3 2018
.UPDATE...
The main changes to the forecast involved the departure of
precipitation from the region and some fog development this
evening. Regional Radars indicate the axis of showers has
shifted just south of Dixie County and the coastal waters.
The high resolution guidance such as the HRRR has a good
handle on this activity, which may occasionally shift into
the far southern Coastal Waters and Dixie County through
around midnight, where there is a chance of showers. Dry
thereafter. Clear skies have developed as of late this
evening from the Western Panhandle into Southwest Georgia
between low clouds across the southeast Big Bend and mid
to high clouds over Southeast Alabama. Under the clear
skies, a saturated near-surface layer and light winds is
promoting the development of some patchy fog already! This
should be short lived however, as the boundary layer wind
increases tonight and drier air advects into the area.
Nonetheless, cannot rule out some patchy dense fog, mainly
north of Interstate 10 and east of the Chatahoochee River.
&&
.AVIATION...
[Through 00Z Wednesday]
VFR through the TAF period with the exception of ABY and VLD
where MVFR in BR is possible tonight. Northwest winds will be
around 5 kt or less tonight, becoming northerly on Tuesday
5 to 10 kt with gusts up to around 15 kt.
&&
.PREV DISCUSSION [631 PM EST]...
.NEAR TERM [Through Tonight]...
Rainfall tapering off quickly tonight as the cold front exits the
forecast area to the south and east. Showers will linger a bit
longer in the SE big bend area, although all areas will eventually
clear out with only some periodic high clouds for the remainder of
tonight. Expect lows in the low to mid 40s for most of the forecast
area, and in the lower 50s for the SE Big bend.
.SHORT TERM [Tuesday Through Wednesday Night]...
Surface high pressure builds in from the west bringing with it a
cooler and much drier airmass. The coldest temperatures will be
Wednesday/Wednesday night with the surface high settling over the
southeast CONUS. Highs will be in the 60s Tuesday and only 50s
on Wednesday. Lows will be in the mid 30s to around 40 Tuesday
night with a widespread light freeze likely Wednesday night across
inland areas.
.LONG TERM [Thursday Through Monday]...
Surface high pressure will continue to move east and weaken
through Friday making way for a vigorous southern stream low
pressure system that will skirt eastward along the northern Gulf
and into our CWA over the weekend. While the latest GFS and EURO
show some subtle differences, especially on timing, both show the
potential for more heavy rain and a possible severe weather
threat. While the system should be progressive, any additional
heavy rainfall could result in additional flash flooding in areas
where the ground remains nearly saturated from recent rains.
Max temps will warm into the 60s Friday and Saturday before
cooling back into the 50s by Monday. Lows will lower to mid 60s
on Friday. Thurs night lows rise into the mid to upper 40s. Lows
will moderate into the 40s and 50s over the weekend cooling into
the 30 and low 40s on Monday.
.MARINE...
Winds and seas will generally remain elevated through the next 7
days with periods of cautionary conditions, including tonight. Small
Craft Advisory criteria may be reached over the weekend as a strong
cold front approaches and pushes through the waters.
.FIRE WEATHER...
There are no fire weather concerns.
.HYDROLOGY...
The Flash Flood Watch for portions of Florida and Georgia has
been allowed to be cancelled early now that the heaviest rains
have moved out of the watch area. All rain will come to an end
this evening as a much cooler and drier airmass moves into the
region behind a strong cold front. However, we will continue to
see River Flooding over the next few days. Another low pressure
system may bring additional heavy rains to our region this
weekend.
.SPOTTER INFORMATION STATEMENT...
Spotter activation is not requested. However, spotters are always
encouraged to safely report significant weather conditions when they
occur by calling the office or tweeting us @NWSTallahassee.
&&
.PRELIMINARY POINT TEMPS/POPS...
Tallahassee 47 63 37 56 33 / 0 0 0 0 0
Panama City 47 61 40 56 37 / 0 0 0 0 0
Dothan 41 58 34 53 31 / 0 0 0 0 0
Albany 43 59 35 54 31 / 0 0 0 0 0
Valdosta 46 62 37 55 32 / 0 0 0 0 0
Cross City 53 68 40 59 34 / 40 0 0 0 0
Apalachicola 49 64 39 57 39 / 0 0 0 0 0
&&
.TAE WATCHES/WARNINGS/ADVISORIES...
FL...High Rip Current Risk until 10 PM EST /9 PM CST/ this evening
for Coastal Bay-Coastal Franklin-Coastal Gulf-South Walton.
GA...None.
AL...None.
GM...None.
&&
$$
UPDATE...LF
NEAR TERM...Humphreys
SHORT TERM...Barry
LONG TERM...Barry
AVIATION...LF
MARINE...Barry
FIRE WEATHER...DVD
HYDROLOGY...Barry