Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 11/25/17
Area Forecast Discussion
National Weather Service Jacksonville FL
653 PM EST Fri Nov 24 2017
...Cooler Tonight with Frost Potential parts of SE GA and Fog
Potential parts of NE FL...
Seasonally cool night expected with below normal min temps
expected across inland SE GA where drier air infiltrated this
afternoon under low level NNW drainage flow around the periphery
of surface high pressure building across the Gulf Coast region.
Dew pts fell into the mid to upper 30s across our NW GA zones,
generally NW of Waycross. If skies were expected to remain cloud
free, the confidence of widespread frost would be elevated across
these SE GA zones, however mid and high clouds are expected to
increase through the night as a mid/upper short wave trough
approaches from the west. Trended min temps down into the
mid/upper 30s from Jesup toward Douglas and included patchy frost.
Confidence of widespread frost not high enough for advisory given
Farther south across NE, clouds will continue to push farther ESE
of the region with drier air filtering southward with mostly clear
skies expected by midnight. Due to recent heavy rainfall and
slower erosion of clouds today generally along and south of a
Gainesville to Palatka to Palm Coast line, ground moisture is very
high. With clearing skies, dry air above the surface, and calm
surface winds, included areas of fog after midnight through about
9 am across our southern FL zones. MOS guidance, SREF, HRRR and
NAM12 all suggest fog potential as well. May turn into more of low
stratus with some model guidance suggesting elevated boundary
layer winds of 15 kts from the west. More mild temperatures will
range in the upper 40s to lower 50s across these zones.
VFR conditions this evening as moisture continued to shift
farther ESE of the terminals. A batch of low cumulus with bases
3-4 kft over GNV is expected to gradually break apart over the
next couple of hours. After midnight, prevailing VFR conditions
were advertised for all terminals except VQQ and GNV where
lingering low level moisture could support fog and low stratus.
Trended VQQ toward marginal MVFR after midnight with elevated
confidence of restrictions to at least MVFR to potentially IFR at
GNV due to higher low level moisture. After sunrise Sat,
prevailing VFR expected under west winds 10 kts or less.
Developing offshore winds this evening are expected to gradually
decrease with seas subsiding through midnight below advisory
levels, but based on recent obs will need to extended SCA for FL
near shore waters. At 6 pm EST, Grays Reef buoy 41008 was down to
5 ft and winds were N 14G18 kts and the Fernandina Beach buoy
41112 reported 5 ft seas. The St. Augustine C-Man SAUF1 measured N
winds 20G21 kts at 6 pm and buoy 41117 offshore of St. Augustine
measured wave heights of 7-8 ft. Will drop the advisory for the
near shore GA waters and replace with SCEC then will extended the
near shore advisory through 1030 pm this evening for the near
shore FL waters due to recent observations.
Rip Currents: Moderate risk this evening. Potential for low risk
for portions of the local coast Saturday due to offshore flow and
.PRELIMINARY POINT TEMPS/POPS...
AMG 39 69 45 67 / 0 0 0 0
SSI 48 69 51 66 / 0 0 0 0
JAX 47 71 48 68 / 0 0 0 0
SGJ 49 70 51 68 / 0 0 0 0
GNV 48 72 47 70 / 0 0 0 0
OCF 49 73 48 72 / 0 0 0 0
AM...Small Craft Advisory until 11 PM EST this evening for Coastal
waters from Fernandina Beach to St. Augustine FL out 20 NM-
Coastal waters from St. Augustine to Flagler Beach FL out
20 NM-Waters from Altamaha Sound GA to Fernandina Beach FL
from 20 to 60 NM-Waters from Fernandina Beach to St.
Augustine FL from 20 to 60 NM-Waters from St. Augustine to
Flagler Beach FL from 20 to 60 NM.
Area Forecast Discussion
National Weather Service Marquette MI
724 PM EST Fri Nov 24 2017
.SHORT TERM...(This evening through Saturday)
Issued at 400 PM EST FRI NOV 24 2017
WV imagery and RAP analysis indicated a mainly zonal mid/upper level
flow across the nrn CONUS with a shortwave trough into n cntrl MN.
At the surface, a 986mb low was located just sw of James Bay with a
cold front extending into nw WI. Radars indicated some sct -shra and
virga into cntrl Upper Michigan with greater rain coverage
upstream from wrn Lake Superior and far wrn Upper Michigan into nw
WI, along and just behind the front.
Tonight, expect the band of rain showers, supported by 800-600 mb
fgen, to advance across the cwa this evening (between 21z-03z) with
the dry slot moving in overnight. Although there may a brief
period of moderate rain, overall amounts should be light,
generally a tenth of an inch or less. CAA will increase overnight
with 850 mb temps dropping to around -10C by 12z. Forecast wet-
bulb zero heights suggest that pcpn will be mainly snow by the
time any lake effect pcpn develops. Instability (water temps near
5C) will be marginal for LES by with favorable 850-750 mb moisture
and inversion heights around 5k ft, some light accumulations,
under an inch, will be possible for nw flow favored locations.
Saturday, the LES will gradually diminish as inversion heights drop
to around 3k-4k ft. However, 850 mb temps to around -13C over ern
Lake Superior will support more widespread -shsn with the potential
for accumulations around an inch. Otherwise, temps will drop closer
to seasonal averages with highs in the lower to mid 30s.
.LONG TERM...(Saturday night through Friday)
Issued at 156 PM EST FRI NOV 24 2017
...No widespread precipitation but could be breezy at times...
Strong west to east jet stream over the northern tier of the Conus
will persist through next week leading to a progressive and overall
warmer pattern. Could still be brief intrusions of cooler air this
weekend and again middle of next week with some light lake effect
but for most part a lower impact and quiet period is expected in
terms of larger scale systems. As a more stronger west to southwest
flow develops aloft next weekend downstream of deep trouging over
the western Pacific/western Conus, does appear a more prolonged
period of warmer weather could develop for the first full week of
December per CFS H5 height/H85 temp anomalies and latest 6-10/8-14
day outlooks from CPC.
To close the weekend expect broad ridge over western North America
with downstream troughing over eastern North America. Brief cold air
shot that brings lake effect early this weekend wanes Sat night but
another shot of colder air will move back in on Sun. May be a brief
period of gusty winds over 30 mph near Lk Superior as that cold air
moves in. Only shallow moisture shown in forecast soundings on Sun
but could be light lake effect over east. May end up only seeing
drizzle though as moisture only extends to temps of -8c which is
borderline to introduce ice in moist layer. Will keep it simple
with just mention of rain and snow showers attm. Any light precip
shuts down Sun night with winds shifting offshore as sfc high
brings in warmer south flow.
Sfc high moves to lower Great Lakes on Mon while stronger shortwave
over western Canada leads to deepening sfc low blo 990mb over the
Canadian prairies. South winds btwn the two sfc features will lead
to warmer conditions over Upper Michigan on Mon. Could be a lot of
mid and even lower clouds around (NAM shows more low clouds trapped
beneath inversion) but even so should see temps similar to what
occurred today (solid mid to upper 40s with even some low 50s). As
bulk of warmest air arrives late in the day on Mon maybe some light
rain could develop over the north. GEM more widespread with light
qpf compared to GFS and ECMWF. May turn breezy ahead of cold front
tied to the low. Strongest winds from southwest would be late Mon
into Mon night. Once cooler air works in Tue aftn and Tue night
could see lake effect for NW flow areas. GFS soundings are pretty
dry blo cloud base and H85 temps around -8c are marginal so any lake
effect looks very light. Gusty northwest winds over 30 mph could
develop along Lk Superior late Tue into Tue night. Temps will bounce
back quickly on Wed, then another shot of colder air moves back in
Thu-Fri of next week. Even with the changeable temps, quick moving
flow aloft looks to prohibit any big systems. However, there is a
hint especially from last few runs of ECMWF of a southern stream
rain/snow system lifting through on Thu with enough cold air behind
for light lake effect.
.AVIATION...(For the 00Z TAFS through 00Z Saturday evening)
Issued at 702 PM EST FRI NOV 24 2017
Rain accompanying a cold frontal passage has resulted in MVFR to
IFR conditions at the TAF sites this evening. Lowest conditions
are at KCMX in an upslope westerly wind flow behind the front.
Behind the front, winds will become gusty at each of the TAF
sites with the strongest winds (to 35 mph) at the more exposed
KCMX site. Light lake effect snow will be possible late tonight
into early Saturday morning; however, ceilings and visibility
restrictions should be limited with continued MVFR conditions.
Expect improvement to VFR Sat afternoon at all sites.
.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 400 PM EST FRI NOV 24 2017
West winds 20 to 30 knots veering nw with a few gale force gusts to
35 knots are expected tonight. Additional gale force gusts of 35
knots are possible on colder northwest flow into the area late
tonight and Saturday. Winds are expected to remain in the 20 to 30
knot range through at least mid weak.
Area Forecast Discussion
National Weather Service San Diego CA
803 PM PST Fri Nov 24 2017
Cooler weather will gradually build from the coast to inland areas
through the weekend. A fast moving low pressure trough will bring
much cooler but nearly seasonable temperatures on Monday with a
chance of light rain showers for all areas except the deserts. As
marine influenced air returns, areas of dense fog could return to
coastal areas this weekend. Gusty westerly winds will develop
over the mountains and deserts Sunday night through Monday night,
turning offshore again by Tuesday morning as the trough passes to
the east. A stronger Santa Ana weather pattern with strong winds
and low relative humidity could develop around Wednesday and
persist through Friday next week.
.DISCUSSION...FOR EXTREME SOUTHWESTERN CALIFORNIA INCLUDING ORANGE...
SAN DIEGO...WESTERN RIVERSIDE AND SOUTHWESTERN SAN BERNARDINO
Tranquil conditions continue across Southern California this
evening after another very warm day. More records were broken yet
...HIGHEST MAXIMUM TEMPERATURE RECORDS BROKEN OR TIED ON NOV 24 2017 ...
LOCATION NEW RECORD OLD RECORD PERIOD OF RECORD
VISTA 89 TIED 89 IN 1975 1957
ALPINE 86 TIED 86 IN 1959 1951
EL CAJON 92 89 IN 1995 1979
BIG BEAR 70 68 IN 1970 1960
CAMPO 88 85 IN 1970 1948
BORREGO 90 87 IN 2012 1942
Satellite imagery shows a mainly clear sky with just a few high
cirrus clouds moving in from the west. Some low clouds have
developed off northern Baja and even just off the southern San
Diego County coast. HRRR shows most of this remaining offshore or
just along the beaches as a weak eddy develops with S-SE winds
keeping most of the low clouds and/or patchy fog just off the
coast overnight, but then moving a bit inland Sat morning. So
some low clouds forecast especially near the San Diego County
coast by Sat morning. No significant changes were made to the
forecast this evening. See previous discussion below for further
...Previous Discussion (Issued at 318 PM PST Fri Nov 24 2017)...
Thin high clouds streaming across Central and Southern California
this afternoon from the subtropics with some wave clouds noted on
the hi-res satellite loops over the Tehachapi Mountains. Far
Southern California remains mainly sunny however.
Temperatures have been trending a few degrees cooler today
although inland and mesa areas remain significantly warmer than
normal for late November with Miramar one of the warmest locations
recently hitting 94 degrees.
The high pressure ridge predominantly responsible for the recent
heat wave will gradually shift SE and replaced with a troughy
pattern through early next week. Gradually cooler conditions will
develop over the weekend with the coolest day likely to be Monday
when a vigorous upper level trough originating from the Gulf Of
Alaska passes through Central California into the Great Basin
through Tuesday. This system could bring some light rain showers
to all areas from Monday morning in Orange County through Monday
afternoon, with chances for rain added to all areas except the
Brief offshore flow still looks to occur Tuesday morning in the
wake of the upper trough with gusts in favorable offshore canyons
and coastal slopes of 30 to 40 mph possible. At this time the
magnitude of this event looks to be moderate at best and only last
for about 12 hours.
Medium range forecaster confidence becomes quite poor Wednesday
and beyond with the EC indicating the potential for another Santa
Ana event but the strongest gradients well to the NE for Thursday
and Friday. A cutoff low may develop off the SoCal coast and
persist through the end of the work week which makes the forecast
of Santa Ana related weather conditions highly difficult this far
out. However without an upper level ridge temperatures will warm a
bit above normal but not likely to be significantly above normal.
250400Z...Coast...Low stratus and dense fog will likely develop near
the beaches late tonight and early Saturday morning with possible
cigs below 400 feet MSL and vis below 1 mile. The chance is low for
a cig at KSAN, KCRQ or KSNA through at least 12Z Sat, though the
risk increases some between 12Z and 16Z Sat for KSAN/KCRQ. Low
stratus/fog could linger along the beaches Sat afternoon and then
spread a few miles inland Sat night. KSAN, KCRQ and KSNA could have
VLIFR or LIFR conditions Sat night.
Valleys, Mountains and Deserts...Mostly sct clouds above 20000 feet
MSL will prevail with unrestricted vis through Sat night.
Areas of dense fog may develop over the coastal waters late tonight
and Saturday morning with a greater chance Saturday night.
Visibility may be reduced to 1 NM or less at times.
A trough of low pressure moving through on Monday will bring
northwest winds gusting 20 to 25 kt over the outer waters.
Skywarn activation is not requested. However weather spotters are
encouraged to report significant weather conditions.
PUBLIC...Gregoria (Update)/Brotherton (Prev Discussion)