Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 10/17/17
Area Forecast Discussion
National Weather Service Charleston SC
1033 PM EDT Mon Oct 16 2017
A strong cold front will move through this evening with dry
high pressure to follow through the upcoming weekend.
.NEAR TERM /UNTIL 6 AM TUESDAY MORNING/...
The strong, secondary cold front will clear the Altamaha Sound
shortly. Cool/dry air continues to advect in from the north
behind the front with dewpoints already down into the lower 50s
across the interior. Most of the rain has pushed offshore, but
some showers will linger near Darien through midnight. Adjusted
pops to reflect this. Breezy conditions will persist through
the night courtesy of post-frontal cold air advection and the
resulting isallobaric rises. Winds could get close to Wind
Advisory criteria for parts of the Georgia coast where gusts
could approach 40 mph at times, so this will have to be watched
carefully, especially in the more exposed Tybee Island area.
Lows will range from the lower 50s inland to the lower-mid 60s
along the Georgia coast where temperatures will be moderated by
the developing northeast, onshore flow.
Lake Winds: As a strong cold front moves across Lake Moultrie
mixing profiles will improve significantly as cooler air moves
across lake waters that are in the upper 70s. Strong low- level
winds along with the air/lake water temperature difference in
the 10-15 degree range should yield winds of 20-25 knots and
some gusts could near 30 kt given winds of 35-40 knots at 925
mb. Thus, a Lake Wind Advisory will run through the night. Waves
will reach 2-3 ft, mainly central and southern parts of the
.SHORT TERM /6 AM TUESDAY MORNING THROUGH THURSDAY/...
The short term will be dominated by high pressure. The broad area of
high pressure is forecasted to be centered to our north.
This high will bring cooler temperatures and dry conditions to our
area, mainly due to northeast flow. Daytime temperature are
forecasted to be below normal Tuesday, then moderating closer to
normal Wednesday and Thursday. Nighttime temperatures will be below
normal Tuesday night with temperatures falling into the mid/upper 40s
inland, and the mid/upper 60s at the immediate coast. Wednesday
night`s temperatures will be closer to normal. The only shower
activity will be over the coastal waters. But it`s not out of the
question that a shower or two could stray onto the beaches,
especially in GA.
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
A deep layered ridge will maintain mostly dry weather and
seasonable temperatures through the weekend. Rain chances may
increase early next week as the high pressure system shifts
offshore and deeper moisture spreads across the area.
.AVIATION /02Z TUESDAY THROUGH SATURDAY/...
* Early risk for showers at KSAV
* Timing for the return of VFR cigs
* Gusty winds
Secondary cold front has cleared KCHS and will cross KSAV by
00z. Risk for showers will continue at KSAV for the next few
hours with even a low probability for a rumble or two of
thunder. Brief stints of sub-VFR vsbys are possible as showers
move through. Suspect most of the activity will be over by 02z,
if not before. May include a TEMPO for MVFR vsbys depending on
radar trends at 2330z. MVFR cigs should only linger at the
terminals this early this evening with VFR conditions expected
to prevail from mid-evening through the day Tuesday. Gusty winds
will also linger with gusts approaching 20-25 kt at times,
especially this evening and again on Tuesday.
Extended Aviation Outlook: VFR.
Tonight: Winds have picked up subtainally across the coastal
waters this evening as post-frontal cold air advection spreads
offshore across the warmer Atlantic waters. RAP 30 meter winds
have been doing an excellent job with the frequent gust
potential so far this evening. Over the past 2 hours, gusts to
33-37 knots have been reported at Buoy 41004, 41029, 41033 and
41008. RAP 30 meter wind progs show winds 36-38 knots for at
least the next 4-6 hours over the Georgia offshore waters and
into the lower South Carolina coast and with water temperatures
generally around 80 across most of the nearshore waters, it
appears the risk for frequest gusts to gale force is becoming
high enough to justify an expansion of the Gale Warning into the
South Carolina nearshore legs. These numbers are also supported
by local research conducted over the summer on post- frontal
cold air events during the fall-winter months. Will keep gales
out of the Charleston Harbor and the Georgia nearshore waters
for now as conditions look too marginal for a warning.
Tuesday through Saturday: High pressure to our north will generate
strong/persistent NE winds. The strongest winds will be on Tuesday,
followed by a gradual downward trend for the rest of the week. For
the waters within 20 nm, Small Craft Advisories will be in effect
through at least Wednesday due to winds/seas. It`s not out of the
question these advisories may be dropped Wednesday night because
models are hinting at improving conditions sooner than what we`re
currently advertising. But opted to leave the end times of the
headlines unchanged until we see another run from the models. For
the GA waters from 20-60 nm out, a Small Craft Advisory will be in
place through the end of the period due to winds and/or seas. For
the Charleston Harbor, the Small Craft Advisory is in effect through
Tuesday evening due to winds. It`s not out of the question this
advisory may be dropped sooner because models are hinting at
improving conditions sooner than what we`re currently advertising.
Again, opted to leave the end time of this headline unchanged until
we see another run from the models.
Strong/persistent northeast winds will push higher water levels
to the coast this week. Minor coastal flooding will be possible
around the times of high tide beginning Tuesday morning and
continuing into at least Thursday. Coastal Flood Advisories will
likely be needed.
Hourly observations and daily climate data from the weather
sensor along Riley Waterfront Park (KCXM) in Downtown Charleston
will not be available until further notice. The cause of the
senor outage is possibly linked to a bad transmitter at the site.
Technicians continue to evaluate the system for a possible
SC...Lake Wind Advisory until 8 AM EDT Tuesday for SCZ045.
MARINE...Small Craft Advisory until 5 PM EDT Thursday for AMZ354.
Gale Warning until 5 AM EDT Tuesday for AMZ350-352-374.
Small Craft Advisory until 8 PM EDT Tuesday for AMZ330.
Area Forecast Discussion
National Weather Service Jackson MS
902 PM CDT Mon Oct 16 2017
Updated for evening discussion.
Forecast remains on track with cooler than average temperatures
expected overnight across most of the area. A few high clouds
remain over the southeastern counties but should gradually push
southeast and out of our area overnight. Winds remain out of the
north and have subsided to generally 5-10 knots across the region
over the past few hours.
Prior discussion below:
Tonight and Tuesday...Latest rap and satellite imagery showed a
strong upper trough moving through the eastern CONUS. This was
dragging a cold front east of the region. Unlike yesterday readings
were more seasonable across the region from the middle 60s to the
lower 70s. Gusty winds of up to 20-25 knots was noted across the
For tonight the winds will diminish to less than 10 mph. It will be
a cool night as high pressure builds in from the northwest with
below average lows from near 40 to the middle 40s.
For Tuesday sunny skies and continued cool conditions will be the
general rule with highs from the lower to middle 70s. The surface
high pressure will build across the region from the northwest as
short wave upper ridging tracks across the region. /17/
Tuesday night through the coming weekend:
Consensus of latest model solutions have come in a little more
stoutly with the warm up and also a little more vigorously with
regard to the upper level trough energy digging toward the south-
central states by the end of the week and through the weekend.
The more pronounced ridging aloft before the trough is the biggest
driver of some slight increases in temperatures (in comparison to
the previous forecast) for the Wednesday through Saturday period.
At least Wednesday and Thursday the atmosphere will remain dry
enough to support large (30+ degree F) diurnal ranges and
overnight hours during this period will still be quite cool and
It is quite possible models still do not have the right idea
concerning south-central states trough evolution toward the latter
half of the period, mainly because this trough is the
manifestation of a large surge of Pacific jet stream energy
cascading through the Pacific Northwest, and then down the lee of
a building ridge near of just offshore of southern California.
Many model solutions have this energy effectively "cutting-off"
near or just to the west of the Lower Mississippi Valley by the
start of next week. If this happens then our region could quickly
get into a cloudy, moist, and rather wet pattern. However, there
is certainly still some potential energy will fail to cut off and
could pass quickly to our north, bringing far less (not to mention
more short-lived) rain chances. For now we have kept from going
too aggressive with rain chances toward the end of the forecast
period (next Sunday/Monday) but basically had little choice but to
at least start introducing some slight rain chances for many
locations by Saturday. At this point the potential for any
hazardous weather through early next week looks pretty low, but I
would not exactly say it is zero either because there is a lot of
jet stream energy that may dig south if model consensus trends
most aggressively for our neck of the woods. For now we are
keeping the HWO clear and will monitor trends in the forecast
00Z TAF discussion:
VFR conditions are expected to prevail for the next 24 hours.
Breezy northerly winds should diminish somewhat, but still remain
around 5-10kts tonight. /28/
.PRELIMINARY POINT TEMPS/POPS...
Jackson 44 74 47 78 / 0 0 0 0
Meridian 44 72 46 77 / 0 0 0 0
Vicksburg 42 74 47 80 / 0 0 0 0
Hattiesburg 46 75 48 77 / 0 0 0 0
Natchez 44 74 49 79 / 0 0 0 0
Greenville 42 72 47 78 / 0 0 0 0
Greenwood 42 73 46 79 / 0 0 0 0
Area Forecast Discussion
National Weather Service Melbourne FL
950 PM EDT Mon Oct 16 2017
Current...After diurnal convection had diminished over the CWA post-
sunset, a few showers initially popped up around Lake County between
before 01Z/9PM, and since then, have really started filling in from
near the westward moving sea breeze over the western peninsula to a
cool front approaching Lake and Volusia Counties from the north.
Otherwise, to the south, skies have cleared save for a few passing
high clouds overhead.
Remainder of tonight...with the approach of the front, residual
instability, coupled with increasing low level convergence and upper
level divergence will support showers and a few storms reaching the
northern CWA after midnight per the solutions of the high-resolution
HRRR and WRF-ARW models. This will necessitate bumping up POPs for
the northern half of the CWA, especially Lake and Volusia Counties
(likely-categorical). While the activity will likely wane some as it
moves into the central CWA late into the overnight period, expect it
will hold together enough to support high chance-likely POPs there.
Flood watch tonight through tomorrow looks like a good call as moist
relatively shallow post-frontal onshore flow spreads about halfway
down the CWA, with gusty onshore flow developing there. Grids will
be adjusted to bump up mainly POPs sky cover through sunrise.
.AVIATION...00Z TAF set that was issued will need to have AMDs for
the northern aerodromes (LEE-DAB-SFB, possibly as far south as ISM-
MCO-TIX) to add some TEMPO SHRA/TS groups, with onset most likely
around 05Z (give or take an hour) north and 08Z-09Z farther south.
Convection should produce IFR VSBYs/MVFR CIGs with local wind gusts
to around 30KT or so possible.
.MARINE...No significant changes. Post frontal wind surge will reach
the Volusia waters well after midnight, where SCA begins then spread
south across the Brevard waters through Tuesday. Evening update Will
increase coverage of showers/storms from the Cape northward,
otherwise, winds and seas look fine.
...Potential For Locally Heavy Rainfall Tuesday and Tuesday Night
Along Portions of the Coast...
...Hazardous Boating Conditions Developing Late Tonight and
Persisting into Late Week...
.PREV DISCUSSION... /issued 347 PM EDT Mon Oct 16 2017/
Tuesday...A frontal boundary will gradually move through north
Florida this evening. Ahead of the front, a sea breeze collision is
expected to occur near the Lake/Sumter County border, which may lead
to an increase in convection near to just after sunset, mainly west
of Orlando. As the front pushes southward through the area later
tonight into tomorrow, moisture, cloud cover and rain chances will
continue to increase. A northeast surge behind the front combined
with deep moisture and enhanced region of upper level divergence
near jet aloft will allow for a favorable setup for training rain
bands with locally heavy rainfall, mainly north of the Cape during
Tuesday into Tuesday night. Area totals of 1-3 inches forecast to
occur from late tonight through Tuesday/Tuesday evening across
Volusia and northern Brevard Counties, with locally higher amounts
possible. This may lead to flooding of roadways, as well as low
lying and poor drainage areas, and have therefore issued a Flood
Watch for this area. Elsewhere scattered to numerous onshore moving
showers across expected across the region with periods of moderate
to heavy rainfall expected. Increased cloud cover/rainfall will lead
to slightly cooler conditions Tuesday, with highs ranging from upper
70s across Volusia to low to mid 80s farther south.
Wed-Thu...High pressure situated over the DelMarVa early Wed will
remain situated over the same general area through the end of the
work week with continued onshore winds over the peninsula. The
previous frontal boundary will wash out on Wed, leaving suitable
lingering moisture through midweek for the possibility of showers
primarily along the coastal Cos and southern sections.
Fri-Sun (modified prev)...High pressure along the NE to Mid Atlc
seaboard will continue a general onshore flow pattern with eventual
airmass drying indicated as higher upstream moisture over the Atlc
basin undergoes subsidence related drying. Marine influence will
keep any temperature extremes moderated with 20 to 30 percent chc
precip is indicated by guid during Fri-Sat with best chances
remaining mainly along the coast. Higher moisture returns Sun,
pushing PoPs to 40-50% area-wide. Seasonal highs in the low 80s
along the coast, mid 80s inland, with slightly above average mins in
the low to mid 70s through the period.
.AVIATION...Scattered SHRA/Isold SHRA will move inland toward
interior terminals KSFB/KMCO/KLEE and KISM through late afternoon
with brief MVFR conds possible with convection. Expect a lull in
rain chances from 00z-06z...before SHRA chances increase late
tonight into Tue morning with a frontal boundary approaching nrn
terminals from KLEE-KDAB aft 08z.
Tonight-Tuesday...Frontal boundary moving into the area later
tonight will lead to rapidly deteriorating boating conditions late
tonight into tomorrow, mainly north of Sebastian Inlet with
northeast winds increasing up to 20-25 knots and seas building up to
7-10 feet. A Small Craft Advisory goes into effect for the
Volusia waters beginning late tonight and then expands southward
across the Brevard County waters into late Tuesday morning.
Wednesday-Friday...Ongoing advisory conditions with winds and choppy
seas will start the period Tue and continue with some degree of
headlines for winds and seas likely for the remainder of the work
week. A long duration of brisk onshore winds through mid to late
week will keep higher seas area wide initially then taper to the
outer waters by the weekend. Rough surf and rip currents with minor
beach erosion at high tide will remain an issue as well.
The middle and upper Saint Johns River basin remains in moderate to
major flood stage, and potential for locally heavy rainfall into
tomorrow across Volusia and northern Brevard counties could lead
to some slight rises into mid week. Otherwise, only a slight
decrease in river levels are forecast over the next several days.
.PRELIMINARY POINT TEMPS/POPS...
DAB 73 79 72 82 / 80 80 60 60
MCO 73 82 70 84 / 50 60 40 50
MLB 74 83 73 84 / 30 70 60 60
VRB 73 84 72 84 / 30 70 60 60
LEE 72 80 67 84 / 50 50 30 30
SFB 72 81 70 84 / 50 70 50 50
ORL 73 82 71 84 / 50 60 40 50
FPR 73 84 71 84 / 30 70 60 60
FL...Flood Watch from late tonight through late Tuesday night for
Coastal Volusia County-Inland Volusia County-Northern
AM...Small Craft Advisory from 4 AM Tuesday to 4 AM EDT Wednesday for
Flagler Beach to Volusia-Brevard County Line 0-20 nm-
Flagler Beach to Volusia-Brevard County Line 20-60 nm.
Small Craft Advisory from 10 AM Tuesday to 4 AM EDT Wednesday
for Volusia-Brevard County Line to Sebastian Inlet 0-20 nm-
Volusia-Brevard County Line to Sebastian Inlet 20-60 nm.
Area Forecast Discussion
National Weather Service Tulsa OK
1104 PM CDT Mon Oct 16 2017
The discussion for the 06Z TAF forecast can be found below.
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM/KROG.
No major changes made to the 00Z forecast, with one exception.
High pressure will remain in control over the region and VFR
conditions will be predominant. The one exception is the
possibility of some fog in the lower Ark river valley near KFSM
during the overnight and into early Tuesday morning. Both the NAM
and HRRR hint at the possibility, and recent obs have mentioned
some patchy fog nearby. Will include a tempo IFR vsby at that
The surface ridge slides east just enough to allow for some
increase in south winds on Tuesday, though it appears that winds
should stay blo 15 kts.
.PREV DISCUSSION... /Issued 909 PM CDT Mon Oct 16 2017/
Surface high across the region will lead to another chilly night
with light winds and largely clear skies. Patchy frost still
appears possible, especially in the favored cool spots in
northwest Arkansas and southeast Oklahoma. Winds have returned to
a light southerly direction in parts of northeast Oklahoma that
typically get locally cooler so think that frost is less likely
tonight than it was earlier this morning. All of this agrees with
the previous forecast, and as such, no update is planned this
PREV DISCUSSION... /Issued 551 PM CDT Mon Oct 16 2017/
The discussion for the 00Z TAF forecast can be found below.
CONCERNING TAF SITES KTUL/KRVS/KBVO/KMLC/KXNA/KFYV/KFSM/KROG.
Surface high pressure will maintain VFR conditions thru the TAF
period. The ridge axis is expected to shift far enough east by
Tuesday afternoon to bring slightly stronger south winds to NE OK,
where gusts could top 15 kts.
PREV DISCUSSION... /Issued 354 PM CDT Mon Oct 16 2017/
Surface high pressure was centered across Eastern Oklahoma to
Southern Illinois this afternoon. Underneath the high...clear
skies and light/variable winds were common across Eastern
Oklahoma and Northwest Arkansas.
Overnight tonight...light winds and mostly clear skies are
expected to continue as the surface high begins to shift eastward.
These conditions will again aid in temps getting down into the mid
30s to mid 40s for much of the CWA. The cold spots tonight look
to be over parts of Northwest Arkansas as they remain on the
westward side of the high pressure center. In response...some
valley locations could see temperatures dip down close to the
freezing mark along with patchy areas of frost. Will hold off on
any frost/freeze headlines for now due to the isolated/patchy
Southerly winds return to the CWA Tuesday and Wednesday and
become breezy Thursday and Friday as an upper level ridge develops
over the Central U.S. At the same time...a slow warming trend is
forecast to begin Tuesday and continue through the week with
possible highs back in the upper 70s/low 80s by Friday.
In the extended forecast...latest model solutions continue to
agree with a wave moving onto the West Coast Thursday night/Friday
and into the Plains over the weekend. Most recent model runs have
begun to indicate the potential for an upper level impulse to
eject into the Southern Plains Friday/Saturday ahead of the main
approaching wave. For now will hold off on introducing pops to the
forecast for Friday to see if indications continue to show up in
later model runs...and will continue with small pops Saturday
ahead of the approaching waves associated cold front. Also ahead
of the approaching cold front...gusty southerly winds are forecast
Friday and Saturday.
Showers and thunderstorms become likely Saturday night for the CWA
as model consensus continues to forecast the cold front across the
region Saturday night into Sunday. As of this forecast...with the
timing of the boundary to be during the overnight/morning
hours...overall severe potentials could be limited. Thunderstorm
potentials look to weaken behind the front and could exit the CWA
Sunday morning with perhaps some rain chances continuing into
Sunday...kind of how the front/precip developed this past weekend.
Will continue to monitor latest data as this forecast will likely
change and will be updated through the week.
.PRELIMINARY POINT TEMPS/POPS...
TUL 44 74 49 77 / 0 0 0 0
FSM 43 73 46 77 / 0 0 0 0
MLC 41 73 45 77 / 0 0 0 0
BVO 38 74 42 77 / 0 0 0 0
FYV 34 69 39 73 / 0 0 0 0
BYV 40 71 43 75 / 0 0 0 0
MKO 43 72 45 77 / 0 0 0 0
MIO 41 71 46 75 / 0 0 0 0
F10 42 72 47 77 / 0 0 0 0
HHW 42 73 45 78 / 0 0 0 0