Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 12/15/18
Area Forecast Discussion
National Weather Service Wakefield VA
1059 PM EST Fri Dec 14 2018
.SYNOPSIS...
Low pressure approaches from the southwest tonight, then tracks
across the local area Saturday. An upper level trough will
remain over the area Saturday night through Sunday. High
pressure returns Monday through Wednesday. The next cold front
approaches from the west Thursday.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
As of 1045 PM EST Friday...
With a break in the rain to just very light rain or drizzle
across portions of south central VA where the melting snowpack
is interacting with rising dew pts, have received some reports
of near zero vsbys in some areas. Have issued a short-fuse Dense
Fog Advisory to account for this (through 2 am Sat for now).
Would expect to see vsbys improve a bit as the rain fills back
in so will re-assess closer to 2 am the need for an expansion in
time and possibly areal coverage.
Latest high res data continues to indicate the heaviest and
steadiest rainfall overnight will be mainly east of I-95 as the
low approaches from the sw late. Can`t rule out some elevated
thunder across the se late as that area is progged to get warmed
sectored as the triple point low crosses the area. Min temps
for the night have been reached as readings have steadied out or
risen over the past few hrs. In addition, areas of fog will
accompany all this making for a rather messy night ahead. Thus,
adjusted the grids based on the current radar and model trends.
Temps by morning should range btwn 40-45 across the Piedmont to
the upr 50s-lwr 60s along the sern coastal areas. Flood watch
remains in affect through late Saturday.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH MONDAY/...
As of 215 PM EST Friday...
Small area of lo pres along the coastal front will be exiting the
VA Capes Sat morning while main occluded lo pres tracks into the
TN Valley. The coastal lo pres will push a frontal boundary
back S (invof the coast) by afternoon. Otherwise...models
showing nebulous sfc pres pattern over the FA Sat...which
suggests keeping conditions cloudy. PoPs will remain quite high
in the morning...then RA will begin to shift to the ENE (and
PoPs lowering in the afternoon). Will keep Flood Watch for the
balance of the day...but it will likely be allowed to end sooner
once RA coverage/intensity lowers Sat afternoon. Will continue
w/ patchy/areas of FG in the morning. Highs around 50F W to the
l-m60s in far SE VA-NE NC (though temperatures likely drop off
during the day).
Upper level system approaches from the W Sat night...w/ most
models showing steady pcpn having ended for most areas. Will
maintain low chance PoPs (~30%) S and high chance to likely
PoPs (far N (50-70%). Cooler, with highs ranging from the m-u40s
N/NW to the m50s SE. Area of SHRAS may linger across the E and
NE Sun night...as low pressure departs the region. 12Z/14 NAM a
bit stronger w/ the departing lo pres just off the srn NJ/DE
coasts Sun evening/night. At this time...appears cold enough
air behind the storm likely arrives after pcpn exits so no
change in ptype expected (late Sun/Sun night) on the ern shore.
Highs Sun in the m-u40s N to the l-m50s SE.
Dry wx returns Mon under NW flow aloft as sfc hi pres moves
through Midwest. Highs in the u40s N to m50s in NE NC.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
As of 130 PM EST Friday...
Hi pres will be sliding across the region Mon night into Tue
night...then offshore Wed. Dry/seasonable wx is expected.
Amplification of trough aloft through the Great Lakes Thu then
to the E Fri...pushes a cold front into/across the local area by
the end of next week. Will increase clouds/PoPs Thu into Fri.
Lows Mon night from the u20s W to the l-m30s at the coast. Highs
Tue ranging through the 40s. Lows Tue night in the m20s inland
to the l30s along the coast in SE VA-NE NC. Highs Wed in the
m-u40s N to the l50s S. Lows Wed night ranging through the 30s.
Highs Thu in the l-m50s N to the m-u50s S. Highs Fri mainly
50-55F.
&&
.AVIATION /04Z SATURDAY THROUGH WEDNESDAY/...
As of 645 PM EST Friday...
Rain continues to overspread the area this evening ahead of an
apprchg low from the sw. Cigs quickly drop to IFR in rain and
fog. Areas of LIFR Fog is possible as well. The low tracks
across nern NC/sern Va Sat morning. Thus, rain/fog continue
through the morning hrs. Thunder was left out of the forecast
attm, but thunder is psbl early Sat morning at ECG/ORF as the
low tracks across the area. The rain becomes more sporatic in
nature Sat aftrn, but IFR CIGS remain. Wind Shear was added to
RCG forecast after midnight. Otw, e-ne winds tonight, become
S-SE along the coast late tonite then w behind the low Sat. RIC
stays ne through the forecast period.
OUTLOOK...
An upper level trough lingers over the area into Sun...IFG CIGS
along with periodic rain/fog likely to continue. Drier wx with
improving conditions arrive late Sun night into Mon and will
then persist through midweek.
&&
.MARINE...
As of 1015 PM EST Friday...
Went ahead and hoisted an SCA for the lower Bay south of New
Point Comfort and the Currituck Sound until 6am Saturday. Quick
surge of onshore winds as gradient ramps up ahead of approaching
low pressure overnight. HRRR and new 00z NMM/ARW each show a
brief 3-5 hour window of marginal SCA winds.
As of 310 PM EST Friday...
A pair of low pressure systems will impact the local waters
tonight through the weekend. E-SE winds of 5-15 kt (up to 20 kt
ocean)are expected thru tonight. Seas are expected to increase
to 5-6 ft across all ocean zones tonight, and SCAs remain in
place to account for this. Winds remain below SCA levels for
the most part, but a brief period of gusts to ~20 kt is possible
tonight over the srn bay/Mouth of the bay. Since wind gusts
will be right around advisory criteria and relatively short
lived, opted to not issue an SCA for the bay attm.
Winds decrease and become more variable over most areas by Sat
PM as the aforementioned sfc low becomes elongated and moves
offshore and a second low pressure center (coupled w/ a closed upper
low) moves over the mountains of WV. However, winds are expected
turn to the NE over the northern ocean zones and remain in the
10-20 kt range through out much of the day on Sat due to the
W-E oriented area of (elongated) sfc low pressure center
centered from WV to SE VA. Therefore, seas likely remain
elevated over the coastal zones through the weekend, but may
drop below 5 ft from late Sat night-Sun S of Cape Charles. Winds
then become more W/NW by Sun evening (and increase to 15-20 kt)
as the secondary area of low pressure moves offshore. Winds
turn more to the NW on Mon evening through Tue AM and increase
to ~20 kt over the bay/~25 kt over the ocean as an upper trough
moves from SE Canada to New England and a shot of colder air
moves into the Mid-Atlantic from the NW. Seas increase to SCA
levels over the srn ocean zones Sunday night, and remain
elevated over northern areas. Elevated seas could potentially
continue through Tue, so current SCAs that go thru 6am Sun may
need to be extended/additional SCAs may need to be issued in the
coming days.
&&
.HYDROLOGY...
As of 1015 PM Friday...
RA/runoff will eventually pose river flood threat along the
James...Appomattox and Chowan Rivers late in the weekend into
early next week. Our latest multimedia briefing at
weather.gov/Wakefield contains the latest information. Please
also refer to the latest River and Lake Summary (WBCRVDAKQ).
&&
.AKQ WATCHES/WARNINGS/ADVISORIES...
MD...None.
NC...Flood Watch through Saturday afternoon for NCZ012>017-030>032-
102.
VA...Flood Watch through Saturday afternoon for VAZ048-060>062-
064>069-075>090-092-093-095>098-509>525.
Dense Fog Advisory until 2 AM EST Saturday for VAZ065>068-079-
080-513.
MARINE...Small Craft Advisory until 6 AM EST Sunday for ANZ650-652-654-
656-658.
Small Craft Advisory until 6 AM EST Saturday for ANZ632>634.
&&
$$
SYNOPSIS...ALB/LKB
NEAR TERM...LKB/MPR
SHORT TERM...ALB
LONG TERM...ALB
AVIATION...MPR
MARINE...JDM
HYDROLOGY...
Area Forecast Discussion
National Weather Service La Crosse WI
538 PM CST Fri Dec 14 2018
.SHORT TERM...(This evening through Saturday night)
Issued at 216 PM CST Fri Dec 14 2018
Early afternoon satellite imagery showed pesky fog/stratus remaining
in place across southeast Iowa and into far south-central Wisconsin.
As for the forecast area, plenty of sunshine was finally seen as the
fog dissipated by mid-day.
The clear skies will last into tonight and combined with the light
winds could lead to fog development once again, along with lows in
the teens or even single digits in favored cold spots. Many hi-res
models are on board with the fog, but notably the RAP and HRRR keep
visibility up over the forecast area. Looking at those particular
models` soundings, they struggle to saturate the low levels and
instead tank the dewpoint as fast as the temperature. However, given
all the melting that will likely occur the rest of this afternoon,
thinking dewpoints are probably underdone. Overall it does look like
a very shallow fog, much like last night, and given pretty good
model agreement (aside from the HRRR/RAP), keeping fog mention in
the forecast. May even need another Dense Fog Advisory for parts of
the area again tonight.
Ridging will be firmly in place on Saturday, with temperatures
generally reaching the mid 30s to lower 40s. Could even sneak out a
few more degrees in some spots depending how quickly any fog
dissipates, as mostly sunny skies are expected for the afternoon.
.LONG TERM...(Sunday through Friday)
Issued at 216 PM CST Fri Dec 14 2018
Sunday will see temperatures in the mid 30s to lower 40s once again.
A weak shortwave trough is still progged to move through the area
during the day, but the associated surface low and precip remain
north of the Canadian border. Northwesterly flow behind the trough
will then lead to a brief cool down for the start of the work week,
with highs in the upper 20s to mid 30s on Monday.
Upper level ridging then works back in for Tuesday, leading to
temperatures back in the 30s for mid-week, but another shortwave
trough looks to dig southeastward toward the area sometime Wednesday
into Thursday. Still some differences in timing and location of
precipitation. The ECMWF remains consistent in amplifying the wave a
bit more than the GFS and brings accumulating precipitation across
much of the forecast area, while the GFS holds much of the
precipitation closer to a surface low over Lake Superior. Either
way, any precipitation looks to move off to the east by Thursday
afternoon, with northwest flow remaining in place for the end of the
work week and into the weekend.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 538 PM CST Fri Dec 14 2018
Lower confidence fog forecast tonight as compared to previous
nights. We did indeed finally see things clear out today, with
just a little mixing out of the boundary layer and moisture,
though some snow melt did also occur. Light winds will remain in
place overnight with high pressure nearby, and have to believe
that all spots will see some reduction in visibility to MVFR or
IFR levels in lighter fog. However, confidence honestly is not
very high with regard to where or if any widespread dense fog will
develop. LSE may actually have the best shot given its valley
location, as RST is likely to see some stronger southerly winds up
to 10 knots later tonight, though quite simply put, we`ll just
have to watch trends through the evening to see how visibility
trends unfold. Suffice it to say that changes to the forecast are
likely over the next 6-8 hours as trends become more clear. The
good news is that any morning fog will again be replaced by
solidly VFR conditions/clear skies after it burns off, with winds
from the south to southeast 10 knots or less.
&&
.ARX WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
IA...None.
&&
$$
SHORT TERM...CA
LONG TERM...CA
AVIATION...Lawrence
Area Forecast Discussion
National Weather Service Charleston SC
1019 PM EST Fri Dec 14 2018
.SYNOPSIS...
A storm system will shift over the region tonight into
Saturday. Dry high pressure is then expected to prevail through
next Wednesday before another storm system possibly affects the
area late next week.
&&
.NEAR TERM /UNTIL 6 AM SATURDAY MORNING/...
The deep upper low to our west has shifted northeast into
Mississippi this evening while water vapor satellite imagery
shows the feed of deep moisture continues to stream into eastern
GA and SC. Latest 00Z NAM12 guidance indicates two areas of
enhanced rains to watch out for overnight. The first is progged
to shift north along and inland from I-95 over our inland zones
where we have seen lesser rainfall amounts today. One inch plus
amount are possible but the heavier of this rain should move
into the SC midlands and Western Pee Dee by 09Z. The second area
of enhanced rains will likely work up and along coastal zones
overnight, fueled by strong low level convergence and theta-e
advection. There is a chance that rains become more convective
along coastal SC where a Flash Flood Watch was maintained in
the Charleston Tri-County area. The new NAM shows 1-2 inch
rainfall amounts will occur just off the coast but we have
noted the latest HRRR recently showing increasing rounds of
more substantial rains for the Central SC coast. Since high tide
was around 1 AM this morning, any rainfall rates of 1/2 to 1
inch per hour could cause further problems and this was our
reasoning for keeping the watch alive. We suspect conditions
will tend to improve by sunrise as the main band of convergence
moves up the coast and north of the area. Temps will remain
steady or slowly rise overnight and there could be patches of
fog just about anywhere overnight. At this time, conditions do
not favor a build-down fog potential given forecast wind fields.
&&
.SHORT TERM /6 AM SATURDAY MORNING THROUGH MONDAY/...
Saturday and Saturday night: Aloft, the large upper low centered
near the Mississippi and Alabama state line will gradually lift
northeastward and into the southern Appalachians during the day.
Then overnight, the upper low will continue to pass by to the north
shifting into the Mid Atlantic. At the surface, the surface low and
attending cold front will shift east of the forecast area in the
morning and precipitation will come to an end in the morning as it
does so. Model time heights and soundings show mid and upper level
moisture stripping out in the morning, ending the heavy rain threat
early. Showers could linger through around midday, mainly along and
east of I-95. Sky cover will improve late in the day and sun could
begin to come out by the late afternoon. Despite being behind the
cold front, temperatures will not cool significantly with highs
ranging in the upper 60s in most locations. Overnight, a dry
forecast is in place with lows in the mid to upper 40s.
Sunday through Monday: Aloft the upper low will move further away
from the region before the next trough approaches from the northwest
and passes through on Monday. High pressure will slowly move across
the central CONUS, beginning to build in from the west on Monday.
Dry air will encompass the area and highs in the low 60s are
expected. Sunday night lows are forecast to fall into the low to mid
40s.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
High pressure from the Great Lakes to the Deep South should move
east and offshore into mid week with a coastal trough developing off
the Southeast U.S. coast. This could lead to a few coastal showers
but there will be a potential for more significant rainfall Thursday
and/or Friday as another storm system possibly affects the region.
Either way temperatures should remain above normal through the
period.
&&
.AVIATION /03Z SATURDAY THROUGH WEDNESDAY/...
Widespread rains should continue overnight at both terminals
with MVFR conditions along with periodic IFR conditions,
especially later on in the wake of a surface low. The forecast
remains tricky in our stable warm sector regime and a pinning
down the lowest conditions overnight in time and space remains
a lower confidence scenario. Conditions will improve on Saturday
as rains taper off and cigs eventually lift to VFR late in the
day.
Extended Aviation Outlook: VFR should prevail Saturday night
through Wednesday.
&&
.MARINE...
Tonight: A surface wave will move across the region overnight
with winds tending to veer to southwest. Speeds will increase
over warmer offshore waters but will continue to struggle
mixing down over the stable cool shelf waters. This evening we
continue to hear some reports of fog around the Savannah River
Entrance and earlier issued a Marine Weather Statements. SCAs
will remain in effect overnight, mainly for seas. Conditions
will be quite unfavorable with widespread moderate to heavy
rains, low vsbys in rain and fog and elevated seas.
Saturday through Wednesday: Conditions will steadily improve across
the local waters on Saturday as a cold front pushes well to the
east. Elevated seas will linger into Saturday night, and the ongoing
Small Craft Advisories will steadily come to an end through Sunday
morning. Thereafter, conditions will remain below Small Craft Advisory
thresholds through the middle of the week.
&&
.HYDROLOGY...
A Flash Flood Watch will remain in effect for the Charleston
Tri-County overnight given already saturated grounds from
previous rainfall. River and stream levels are also likely to
rise. Several rivers across the area are already at/above flood
stage, and could rise higher into next week. Other rivers could
approach or reach flood stage too by early/mid next week.
&&
.CLIMATE...
New record rainfalls for the date have been set at North
Charleston and Downtown Charleston. No record yet at Savannah,
but rains continue to fall. Record reports will be issued at
midnight. Current rains as of 1015 PM EST:
KCHS - 2.89 (new record) and KSAV- 1.40
&&
.CHS WATCHES/WARNINGS/ADVISORIES...
GA...None.
SC...Flash Flood Watch through Saturday morning for SCZ044-045-050-
052.
MARINE...Small Craft Advisory until noon EST Saturday for AMZ352.
Small Craft Advisory until midnight EST Saturday night for
AMZ350.
Small Craft Advisory until 6 AM EST Saturday for AMZ354.
Small Craft Advisory until 6 AM EST Sunday for AMZ374.
&&
$$
NEAR TERM...
SHORT TERM...
LONG TERM...
AVIATION...
MARINE...
HYDROLOGY...
CLIMATE...
AREA FORECAST DISCUSSION...UPDATED
National Weather Service Jackson KY
1020 PM EST Fri Dec 14 2018
.UPDATE...
Issued at 1020 PM EST FRI DEC 14 2018
Updated the forecast into Saturday morning mainly to adjust the
PoP grids in order to better incorporate the current lull and the
development of more pcpn late tonight based on the latest near
term guidance. Have also added in the current obs and trends for
the T and Td grids. These updates have been sent to the NDFD and
web servers along with a freshened set of zones.
UPDATE Issued at 645 PM EST FRI DEC 14 2018
23z sfc analysis shows low pressure moving into the Tennessee
Valley from the southwest. This is spreading a healthy and
sustained band of rain showers across the northwestern three-
quarters of the CWA with up to an inch falling as this area slowly
lifts through the CWA for most places. Downsloping on the east to
southeast winds of 5 to 10 mph is likely helping to limit the
showers in the far southeast this afternoon and evening. Do still
expect a bit of a lull later this evening and into the first part
of the night as the better upper level support moves off to the
northeast. A stray thunderstorm remains possible with the heaviest
of the showers, but most places will miss out. Currently, with
the wet environment, temperatures are fairly uniform across
eastern Kentucky and generally in the upper 40s to low 50s with
dewpoints within a degree or two of 50 degrees most places. Have
updated the forecast through the rest of the evening mainly to
fine tune the PoPs with the first batch of showers slowly winding
down to a lull - in line with the latest HRRR guidance. Did also
incorporate the current obs and trends into the T and Td grids.
These updated grids have been sent to the NDFD and web servers. A
zone update will be issued later this evening to better time the
best shower chances after midnight - and to remove evening
wording.
&&
.SHORT TERM...(This evening through Saturday night)
Issued at 419 PM EST FRI DEC 14 2018
The afternoon surface analysis reveals an area of low pressure
progressing across the Lower Mississippi River Valley and south
to southeast flow streaming into eastern Kentucky. In the upper
levels, we are still watching a mature vertically stacked closed
low that will slowly progress northeast into the Tennessee and
Ohio Valleys. This flow is out of the southeast and is leading to
some downsloping in the southeast part of the region, and
therefore lesser precipitation amounts and even dry in some cases.
However, upper level divergence, a low level jet across the
Tennessee Valley and some frontogenetical forcing aloft is leading
to decent rainfall across the heart of the CWA down to the Lake
Cumberland region. We will continue to see moisture stream out of
the gulf, with fairly anomalous PWAT values of greater that 1 inch
pouring into the region. This will lead to additional rain
showers and even a few thunderstorms developing under some
marginal instability this evening into tonight. The models do hint
at a decent deformation zone developing mostly north of the
region overnight into Saturday, and this will lead to better
chances of seeing higher QPE values along and north of I-64. This
is where we have forecast amounts of 1.5 inches, with isolated
higher amounts possible if thunderstorms develop and depending on
where the better deformation zone lines up.
Saturday the vigorous upper level low and surface low will
progress across the Tennessee and Ohio Valleys. This will lead to
the aforementioned deformation band across northern Kentucky and
will likely lead to a overall lull in rain showers across areas
along and south of the Mountain Parkway early Saturday. Then
another area of showers will track out of the Tennessee Valley
and into eastern Kentucky by Saturday afternoon and evening. This
will lead to another round of QPE, with amounts generally around
0.25 to 0.50. After this, not much in the way of moisture will be
left and we will see energy begin to get transfered to the
developing low along the east coast Saturday night.
.LONG TERM...(Sunday through Friday)
Issued at 419 PM EST FRI DEC 14 2018
Cold core low will be migrating just east of the Commonwealth Sunday
morning with post-frontal/upslope induced rain showers continuing
across far eastern Kentucky into the afternoon. A secondary upper
low will be diving southeast across the Great Lakes late Sunday into
Monday. This northwest flow regime will keep temperatures in check,
with highs Sunday and Monday generally in the upper 40s. Relatively
normal ridge/valley temperature splits look likely as surface
ridging builds in from the west, allowing winds to subside and skies
to clear.
Upper ridging and subsequent rising heights moving east from the
nation`s midsection will bring dry weather to eastern Kentucky for
early-mid week. However, Tuesday will bring near to below normal
temperatures as surface ridging across the Ohio Valley keeps a cool
dome locked in and negates any appreciable warm air advection during
peak heating. Temperatures look to rebound into the 50s Wednesday as
this surface ridge moves east off the mid-Atlantic, allowing for
warmer southwesterly flow to take hold of eastern Kentucky downwind
of cyclonic flow spanning the southern Plains to upper Midwest.
The tandem of northern and southern stream systems will spell
increasing rain chances for Thursday into Friday, with perhaps
enough cold air spilling in on the backside of the system for a
little snow. A great deal of uncertainty remains on this potential,
regarding whether the northern or southern stream system becomes
dominant or if they phase.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
ISSUED AT 715 PM EST FRI DEC 14 2018
CIGs will slowly decrease to MVFR through the evening for the ones
that have not already dropped down there with the showers. Have
also allowed for some VLIFR CIGs along with fog as the heavier
showers pass at a couple of the sites through late evening - via a
tempo group. Expect the prevailing conditions to drop to IFR or
lower at times later tonight into Saturday for most sites. Looking
for a lull in the pcpn for Saturday morning before the shower
chances tick up in the afternoon - though have allowed for CIGs
to come up to mid range MVFR. Winds will remain light through the
TAF period.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...GREIF
SHORT TERM...DJ
LONG TERM...GUSEMAN
AVIATION...DJ/GREIF
Area Forecast Discussion
National Weather Service Miami FL
724 PM EST Fri Dec 14 2018
.AVIATION...
Main concern through TAF cycle will be approaching frontal boundary.
Current timing has it reaching KAPF 07Z-08Z and east coast 10Z-
12Z as it breaks apart. All locations may see additional -SHRA
ahead of this line. TSRA threat looks minimal at this time, so
have kept VCSH. Slow movement will keep -SHRA in vcnty through TAF
cycle. SSE winds 8-12kts overnight, becoming SSW with pre-frontal
boundary, gusty SW after 16Z tomorrow.
&&
.UPDATE...
A few anticipated changes with this evenings update. Mainly to
back off PoPs this evening. The front is slow moving and no
significant showers are even close to South Florida. The HRRR
continues to show most of the activity holding off until 03-05z,
or between 10pm and midnight est. So, dropped PoPs across the
area, and even removed mention this evening for the east coast
until after 03z, and even then it is only a slight chance. Kept
chance PoPs for the east coast after 06z, although it may be
closer to dawn before showers get near the Atlantic coastal areas.
The Gulf coast has better chances earlier, as the front is
approaching from the west. There is still the possibility of some
general thunderstorms for the area through tomorrow evening as
well.
&&
.PREV DISCUSSION... /issued 352 PM EST Fri Dec 14 2018/
DISCUSSION...
Big stories for the week are the cold fronts tonight and another
at the end of the week. however, they do not look to bring as cold
an air mass as the last front.
The current setup starts with a 500mb and surface low are over
Louisiana, with a cold front nearing the western edge of the
Florida Panhandle, stretching southward well into the Gulf. Models
are indicating the low will be fairly slow moving, moving over
Alabama by around 03z, or 10pm est, tonight, and the cold front
still not through the Tallahassee area. There also appears to be
a pre frontal surface trough that is well ahead of the main front.
This trough is what may initiate some stronger showers and storms
over Central Florida. There is also a 250mb jet that may be
helping to amplify convection in central Florida. However, these
dynamics should stay well north of South Florida, keeping us
fairly quiet for this evening and mainly showers and some general
thunderstorms over night. Looking at the HRRR, convection may not
even make it into the western lake region until are dawn. There
may also be a few showers over the Atlantic waters, and possibly
the Atlantic coast. Most likely the forecast is too aggressive
with pops this evening, even though it is lower than the model
guidance. Would not be surprised if the overnight hours are
mostly dry. So confidence, even in the short term is pretty low.
That said, only brought low end chance PoPs over the the eastern
South Florida area late this evening. Would not be surprised if
evening updates backed off on these numbers. The front itself will
creep across the area through the day tomorrow, and should be
exiting the Atlantic coast sometime in the late afternoon hours.
This would keep chances for showers and thunderstorms in the
forecast for the day tomorrow.
Behind the front, high pressure is forecast to build in for
tomorrow night into Sunday. The cooler air mass will take its
time moving into the area. Highs on Sunday are forecast to be
somewhat cooler, in the 70s across the area. Lows Sunday look to
be around 10 degrees F cooler than Saturday morning. By Monday,
the cooler air advects in and lows across the region will range
from the upper 40s in the western lake region, to the upper 50s
for the Gulf coast, to around 60 along the Atlantic coast. The
western Miami to Palm Beach metro areas are forecast in the upper
50s. The dry air will take a little longer to move in, not
significantly dropping until Monday, when they are forecast to be
in the 50s.
The coolest day looks to be Monday, then a gradual warming trend
for the middle of the week, under high pressure. At least until
late Wednesday night, into Thursday morning.
Overnight Wednesday, a 500mb trough moves off the Texas coast.
Ahead of it, the models are indicating some cyclogenesis over the
the western Gulf. Models are hinting it may interact with the
frontal boundary, from tomorrows cold front, which looks to stall
over Cuba, and stretch well back towards southern Texas. The
developing system should lift this front to the north, as a warm
front on Wednesday night spreading showers well out ahead of it.
As this system develops over the Gulf, there is a second system
over the hudson Bay in Canada. This system is associated with a
much strong upper level low that will absorb the southern system.
As it does, the system becomes an extended cold front stretching
from new England down to Cuba. This system looks to likely bring
just another round of mainly showers to the area at this time,
although some thunderstorms may need to be added in as it gets
closer in time. This front is currently progged to move more
quickly and exit South Florida by next Saturday morning.
MARINE...
A cold front is forecast to slowly move through the area from
tonight through tomorrow night. This will shift the wind to the
northeast by Sunday morning. However, the wind is not forecast to
be above any advisory criteria, or even enough to build seas above
5 feet in the offshore Gulf waters of South Florida. For the
Atlantic seas are only forecast to build to around 3 feet in the
Gulf Stream on Sunday. So, while small craft should exercise
caution, no advisory will be issued at this time for tonight or
tomorrow, and the current advisory will be cancelled with this
update.
Behind this front, high pressure is forecast to build over the
area, with cooler temperatures for the beginning to the middle of
the week.
Also, the High Risk of Rip Currents will be allowed to expire this
evening, as the wind is forecast to become more southerly
overnight, and persist out of the south most of tomorrow. This
would likely induce more of a longshore current, which would help
to lessen the risk of rip currents.
&&
.PRELIMINARY POINT TEMPS/POPS...
West Palm Beach 73 81 61 74 / 40 60 40 10
Fort Lauderdale 73 82 65 76 / 50 50 50 10
Miami 74 81 66 75 / 50 40 40 10
Naples 72 76 64 75 / 70 50 10 0
&&
.MFL WATCHES/WARNINGS/ADVISORIES...
FL...High Rip Current Risk until 7 PM EST this evening for FLZ168-172-
173.
AM...None.
GM...None.
&&
UPDATE...13
AVIATION...88/ALM
Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
609 PM CST Fri Dec 14 2018
.UPDATE...
Issued at 545 PM CST Fri Dec 14 2018
Updated to include 00z aviation discussion below.
&&
.SHORT TERM...(This evening through Saturday night)
Issued at 253 PM CST Fri Dec 14 2018
After days of fog and stratus, today`s sunny skies are very much a
welcomed change. Where the snowpack is thin across western MN, we
have seen many sites top out in the 40s. This nice weather is the
result of the continued split flow, with us in between the northern
stream up across central Canada and the southern stream closed low
over the southeast.
Biggest change in this forecast was to significantly pull back on the
fog mention for tonight. The HRRR has done a good job on a nightly
basis with depicting the general evolution of the fog/stratus and it
has been consistent today in showing pretty much no fog within the
MPX area tonight. The near surface moisture layer will be even
shallower tonight than it was last night, which supports a lack of
fog. In addition, we saw the fog last night dissipate during the
overnight hours, indicating the atmosphere that we have had come in
is not very supportive of fog. The surface ridge axis tonight will
be spread out from southeast Neb, southeast MN to the WI/MI border,
so the greatest threat for seeing fog tonight will be near this
feature across southeast MN and central WI. In all likelihood, there
will be some freezing fog in this region, but no where near the
extent we have seen the last few days.
For Saturday, it will be another beautiful sunny day. Given the fact
that temepratures today are running at the top end of the model
spread envelope, bumped up highs for Saturday toward the high end of
the guidance envelope, with mid 40s expected out in west central MN,
with the Twin Cities again taking a run at 40.
Saturday night, the wave that is coming ashore in the Pac NW this
afternoon will be coming across the upper MS Valley. This will send
another surface trough across the area, but it will be completely
moisture starved, so will do no more than lead to an increase in
high clouds, though the combination of cloud cover and winds
remaining through the night will result in milder lows (teens
unlikely) and a minimal threat for fog Saturday night.
.LONG TERM...(Sunday through Friday)
Issued at 253 PM CST Fri Dec 14 2018
Overall, a benign forecast with the next chance for precipitation
not coming until the middle of next week.
By Sunday, the cold front will have moved through the forecast area
with 10-15 MPH northwest winds likely through the day. The air mass
behind the front will be quite mild, so the front is moreso a simple
wind shift. With ample dry air behind the front, sunny skies should
prevail and temperatures should have no trouble reaching the mid 30s
without any cold air to our northwest. Monday will be cooler with
the ridge axis moving through the area. The sunny skies will
continue with no weather systems near the area.
Tuesday and Wednesday look mild with southerly flow developing as
the surface ridge slides to our east. Would not be surprised to see
readings reach 40 degrees on either day. Meanwhile, the next system
to watch will be a shortwave emerging from southern Alberta, racing
east-southeast and reaching Minnesota Wednesday night. This clipper
could provide a quick shot of snow to the area, but at this time
most of the deep moisture and lift looks to hit northern MN more
directly. Once the front associate with the clipper goes through,
strong northwesterly winds will develop. Could see the potential
for 30+ MPH gusts for next Thursday.
&&
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 545 PM CST Fri Dec 14 2018
More of an optimistic forecast for the overnight hours in this TAF
set than in previous nights due to shallower moisture and the
center of high pressure shifting from northern IA into central WI.
Overnight fog looks to be restricted to far eastern MN through
western WI, thus making KRNH-KEAU most susceptible but leaving
the possibility open for KMSP. Otherwise, little to no clouds will
be the story through the next 24 hours. An approaching low level
jet streak in advance of an approaching dry cold front for Sunday
will enhance winds in the 1-2 kft level tomorrow afternoon to
tomorrow evening. Have shown this thus far in western MN with LLWS
mention, with it likely translating to eastern MN and western WI
after 00z tomorrow evening.
KMSP...Fog chances are much lower than in previous evenings but
cannot be ruled out altogether, especially given that IFR readings
were prevalent with SE winds 2 mornings ago and SW winds this past
morning. However, shallower moisture looks to make fog less likely
at MSP. Plus, MSP is commonly the last terminal to deal with fog,
even while the metro satellite airports report it. At this point,
will show the uncertainty with a TEMPO MVFR mention and adjust as
needed.
/OUTLOOK FOR KMSP/
Sun...VFR. Winds NW 10G20 kts.
Mon...VFR. Winds light and variable.
Tue...VFR. Wind SW 10G20 kts.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
&&
$$
UPDATE...JPC
SHORT TERM...MPG
LONG TERM...SPD
AVIATION...JPC
Area Forecast Discussion
National Weather Service Topeka KS
506 PM CST Fri Dec 14 2018
...AVIATION UPDATE...
.SHORT TERM...(This evening through Saturday)
Issued at 227 PM CST Fri Dec 14 2018
The upper low and associated trough continue to slowly move east
away from the region while weak high pressure at the surface has
moved into the region from the higher terrain of NE/CO/WY.
Drying/subsidence near the ridge axis is helping to lower
dewpoints into the upper teens and lower 20s across the area which
could have implications on lows tonight. Given clear skies and
winds which should become calm after midnight expect strong
radiational cooling with lows expected to drop toward current
dewpoints. Cannot rule out patchy fog but lack of recent rain and
a full day of drying sun should help keep areal coverage of any
fog limited to local effects/near rivers tonight. The sfc ridge
will move over the area on Saturday with sunny skies and light
winds which should help air temps reach into the 50s so a great
day appears in store for Sat.
.LONG TERM...(Saturday night through Friday)
Issued at 227 PM CST Fri Dec 14 2018
The overall weather pattern is forecast to remain mild and mainly
dry through next week. A weak system is forecast to move through
the region Tues into Weds with only low precip chcs and that
should be mainly rain given how warm temps will be. Aside from
that system no other storms appear on the horizon as we head
toward the end of next week with warmer than avg conds forecast to
persist into late week.
&&
.AVIATION...(For the 00Z TAFS through 00Z Sunday)
Issued at 506 PM CST Fri Dec 14 2018
Dewpoint temps mixing out into the teens late this afternoon
raises some considerable doubts about radiational fog overnight.
And the latest RAP forecast soundings struggle to saturate the
boundary layer with any moisture remaining very shallow.
Therefore will remove the mention of fog as even the objective MOS
guidance fails to generate any fog. The dry air with the surface
ridge should lead to VFR conditions prevailing.
&&
.TOP WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM...Omitt
LONG TERM...Omitt
AVIATION...Wolters