Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 04/15/19
Area Forecast Discussion
National Weather Service State College PA
1047 PM EDT Sun Apr 14 2019
Low pressure over the Ohio Valley will track across upstate
New York tonight, as the trailing cold front pushes through
Pennsylvania. Upper level ridging is expected over the region
during the middle of the week, then a slow-moving cold front
will likely push into the region late Friday into early
.NEAR TERM /UNTIL 7 AM MONDAY MORNING/...
Tornado Watch continues for most of the area, but the far NW
where the best instability has passed through as the main line
of damaging convection pushed past. Still strong shear and some
D-CAPE to be dealt with. Many spinning cells thus far, but no
specific reports of actual tornadoes. Big line is breaking up a
bit, but also accelerating. Thus, the threat for wind damage is
still on-going. The threat for tornadoes may be a little lower,
now, as the instability has waned, but the threat for tors
along/inside the main line remains high.
Expect sct shra thru the next few hours in the NW, but action
has shifted to the east. Expect the tiny cells over the central
counties to fill in and perhaps organize a bit - esp if they are
more in the north where the shear is best. Main shortwave which
forced the earlier convection in the SE has push most of that
to the NE and out of the area.
The main line should pass through the far SErn counties by
07-08Z right around end time of the watch. Will trim the watch
.SHORT TERM /7 AM MONDAY MORNING THROUGH 6 PM MONDAY/...
Blustery and much cooler conditions are expected Monday, as
strengthening low pressure passes north of Pa. Passage of upper
trough will likely produce scattered rain/snow showers across
the Allegheny Plateau. However, surface temps should remain too
warm for any snow accumulations. A downsloping westerly flow
should result in dry weather across the Susq Valley. However,
cold temps aloft will likely result in a good deal of stratocu.
Bukfit soundings support wind gusts Monday afternoon close to
40kts across southern PA, so later shifts may need to consider
a possible wind advisory.
.LONG TERM /MONDAY NIGHT THROUGH SUNDAY/...
Left mentioned of some showers in for later Tuesday into Thursday.
Much of this time will be dry.
The main issue will be another huge weather system by Friday.
Showers and some thunderstorms will be associated with this
For now, just minor adjustments.
For later Saturday into early next Monday, the risk of showers
tapers off. GFS and EC still different from run to run and day
to day, on how the upper level trough may split apart, and dig
southeast. This will make a difference on how things linger past
Either way, not looking quite as cold as it did several days
ago. Thus the chance of any snow showers on the back side of the
storm is less now.
.AVIATION /03Z MONDAY THROUGH FRIDAY/...
A line of showers adn thunderstorms is making its way across
central PA from 02Z until 10Z.
It has caused a period of IFR and lower cigs and vsbys in
thunderstorms. Expect this to occur at all TAF sites at times
overnight. Light showers are out ahead of the line which will
mainly affect IPT and MDT.
An area of showers behind the front will drop cigs and vsbys
Behind the front which is occurring at BFD.
Westerly flow will pick up with a period of gusts to 30-40 mph
Monday along with ceiling restrictions that will be mainly
confined to the western/northern terrain.
Mon...AM Rain and restrictions. Becoming windy.
Tue...Trending VFR; winds subsiding.
Wed-Thu...Chance of a shower. Mainly VFR.
Fri...Widespread restrictions likely with showers and
Main line has passed through the NW, but additional rainfall is
possible. Watch only goes through 2 AM, and rain poss thru then.
Will hold onto it there. Showers finally popping up in between
the SErn cluster and the big line, but not much QPF just yet.
HRRR continues heavy rain with the line, and threat for heavy
rain still goes for most of the night for the SE.
0.75-0.90" of rainfall through the day today over the NW has
things very wet and many of the smallest waterways are likely
high/nearly full. The line of convection to the west is
advancing slower to the east than the elements are moving N/NE.
They could also receive more than one thunderstorm this
evening/early tonight. Felt the threat was much higher than FFG
may reflect there with most of the water not accounted for in
the guidance. Plus, we are solidly in the SLGT risk of excessive
rain per WPC guidance.
The southeastern counties got some heavy rain and patchy
flooding two days ago, and they are starting to pick up some
rain now. There is some thunder embedded in the stuff moving up
from MD/VA. HRRR paints a few stripes of >1" rain in convection
there. The Front and associated thunder/heavy rain does not
arrive until late tonight, and we are always wary of overnight
convection. The deep 60+KT LLJet is loaded with moisture. 1 hr
FFG ranges between one inch and two inches. We will also have to
watch out for the Swatara Creek which is running high and is
arguably the wettest basin around the state right now.
Flash Flood Watch until 2 AM EDT Monday for PAZ004-005-010.
Flash Flood Watch until 6 AM EDT Monday for PAZ036-056>059-
Area Forecast Discussion...Updated
National Weather Service Peachtree City GA
1020 PM EDT Sun Apr 14 2019
Line of showers/storms moving through far east central GA and should
be out of the forecast area by midnight. Wind Advisory has expired.
Winds should remain generally gusty overnight...but remain below
.SHORT TERM /Rest of today through Monday Night/...
While the first prefrontal wave of precip and embedded
severe/tornado potential is exiting over portions of east central
Georgia, the next focus will be with possible convective
redevelopment along a confluence zone in north GA/central TN. SPC
has this area in a meso discussion to where the shear and
some increasing instability with previous clearing could allow for
another round of strong to severe storms capable of hail, damaging
winds, and tornadoes. The HRRR and Nam Nest models have
consistently indicated such convection occurring over the last 2
days of runs. Cannot rule out another Tornado Watch in the next
hour or two.
Otherwise drier air will build in tonight through Monday Night
into midweek as a strong ridge builds in.
.LONG TERM /Tuesday through Saturday/...
Forecast looks largely on track with next storm system still in
the late Thurs/Friday period and lingering upper trough influence
going into the weekend. No changes made and previous discussion
.LONG TERM /Monday Night through Saturday/...
Extended forecast starts with high pressure over the area, lasting
through mid week. Next system moves in late Thursday, and have
backed off pops Wednesday given the slightly later model
solutions. Strong frontal system looks well organized and brings
the next chance for severe storms. SPC already highlighting the
area for Day 6 and 7 severe threat risk, and so this system will
certainly be the forecast concern through the latter half of the
A secondary wave swings through the long-wave trough Friday night
into Saturday, keeping chance pops in the forecast. High pressure
returns to the state late Saturday. Saturday, expect the coolest
temperatures for the week, with highs only in the 60s, and lows
largely in the mid to upper 40s by Sunday morning.
Line of showers/thunderstorms moving into east and central GA
will affect KAHN and KMCN within next few hours. After that only
expect a few showers overnight across the area. Ceilings should
lower to mvfr before 06z and improve to vfr after 14z. Gusty
SW winds overnight will become NW and gusty after 12z.
//ATL Confidence...00Z Update...
Medium on overnight cigs.
High on all else.
.PRELIMINARY POINT TEMPS/POPS...
Athens 76 45 67 45 / 100 30 0 0
Atlanta 76 45 66 48 / 100 30 0 0
Blairsville 71 37 59 40 / 100 40 0 0
Cartersville 78 42 65 45 / 100 30 0 0
Columbus 79 47 71 48 / 100 20 0 0
Gainesville 74 44 64 45 / 100 30 0 0
Macon 79 47 69 46 / 100 20 0 0
Rome 77 42 66 44 / 90 30 0 0
Peachtree City 78 43 68 45 / 100 20 0 0
Vidalia 83 52 72 49 / 80 40 0 0
Area Forecast Discussion
National Weather Service Grand Forks ND
1009 PM CDT Sun Apr 14 2019
Issued at 1007 PM CDT Sun Apr 14 2019
First area of showers moving into the DVL basin with a few more
showers west of that toward Minot and also extending toward
Bismarck. HRRR and other CAMs indicate best shot of showers
tonight remain along and north of Hwy 2...but did extend pops a
tad farther south. But precip is falling from mid cloud deck so
not expecting more than a few hundredths. Temps as clouds thicken
and precip moves in will be above freezing and suspect more liquid
than anything, but some wet snow mix may occur.
.SHORT TERM...(This afternoon through Monday night)
Issued at 323 PM CDT Sun Apr 14 2019
Showers associated with WAA ahead of mid level shortwave trough
beginning to move from western ND into central ND. This activity
should overspread our CWA tonight, with main track favoring
locations north of Highway 2 closer to axis of better/more organized
forcing. Potential for showers still extends across much of our
CWA, but overall would be more isolated. P-type still most likely
rain or snow and any snow accumulations would be light (less than
one inch). This activity should exit the region to our
east/northeast Monday morning, with dry westerly flow overspreading
our CWA Monday.
Where precip occurs temps may hover just above freezing, and winds
may also help mix low levels even in areas with good clearing
holding overnight lows up. Temps will be quite mild Monday and
depending on clearing, strength of westerly flow, and impact of
lingering snow pact, locations as far east as the Red River could
reach 60. Areas over snow pack may still hover in the 40s Mon.
.LONG TERM...(Tuesday through Sunday)
Issued at 323 PM CDT Sun Apr 14 2019
Another storm system is posed to bring widespread rainfall to the
region by the middle of the work week. Luckily, temperatures will
see a warming trend through the week that will promote rainfall over
snow. Additional light rain chances are possible by the end of the
week and into the early weekend.
Fairly benign weather is anticipated on Tuesday as temperatures
continue to warm into the 50s and low 60s across the region. Cloud
cover will gradually increase Tuesday night into Wednesday.
Wednesday through Thursday...
Model guidance has come into fairly good agreement that another high-
amplitude upper level trough will propagate into the central Plains
by Wednesday. Unlike the previous storm that brought snow to the
region last week, weaker differential vorticity advection over a
deepening lee cyclone will allow for an overall weaker and more
elongated surface low as it moves into the eastern Plains/upper
Midwest region. The implication of this is that sub-freezing arctic
air is not as likely to surge southward as in the previous storm.
This, along with a relatively warmer airmass already in place, will
help promote mainly rain as the likely precip type.
Rain is expected to begin across the Dakotas Wednesday morning
before spreading eastward through the day as broad synoptic lift
associated with the main upper level wave overspreads the region.
Generally, rainfall chances and amounts increase southward from the
international border towards the ND/SD/MN tri-state region. Recent
deterministic guidance, and several GEFS members, are beginning to
suggest relatively high QPF amounts (in the 0.5 to 1 inch range) are
possible roughly south of the Highway 2 corridor. These higher QPF
amounts are being driven by a strong 850-700mb frontogenesis signal
and may be augmented across the tri-state area by weak mid-level
instability. Given the synoptic pattern this scenario is possible,
but the placement of the higher QPF amounts will largely be
dependent on the track of the low.
Although rain is going to be the primary precip type, a bit of snow
can`t be ruled out as the system slowly exits the region from west
to east on Wednesday night/Thursday morning. This snow is mainly
being driven by diurnal cooling and likely won`t lead to any
impactful accumulation amounts. Temperatures rebounding into the 50s
on Thursday will help melt any potential snow accumulation.
Friday through Saturday...
Temperatures will once again slowly climb back into the upper 50s
and low 60s for Friday and Saturday. Upper level ridging over the
Plains on Friday will help direct an upper level shortwave over the
Canadian Rockies and across the international border region. An
attendant surface trough/weak cold front will likely propagate
through the region late Friday and into early Saturday. Scattered
rain is likely along this front, but widespread heavy rainfall is
not expected at this time.
.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 647 PM CDT Sun Apr 14 2019
VFR thru the pd as extensive high and mid level cloud cover move
thru in association with the 500 mb vort. South-southeast winds
will remain mostly in the 10 to 20 kt range thru the night, though
lighter BJI area.
Issued at 950 PM CDT Sun Apr 14 2019
North Dakota Tributaries: The Sheyenne River at Kindred and the
Maple River at both Enderlin and Mapleton are expected to rise to a
secondary crest later this week as snow melt will combine with
expected rainfall. River levels will continue falling at West Fargo
and Harwood along the Sheyenne River. Rainfall forecast will be
monitored closely in the coming days as there is the potential for
heavier rainfall for the southern portions of the Red River Valley
towards mid week.
Northwestern Minnesota Tributaries: The latest forecast for
northwestern Minnesota Tributaries has the South Fork Buffalo River
at Sabin rising once more to a secondary crest this week. This is
mainly in response to the melting of snow from last weeks winter
storm. Additionally, we will see rises along the Buffalo at both
Hawley and Dilworth as well as the Red Lake River at Crookston. The
Wild Rice, Sandhill, and Marsh Rivers are all on track to continue
falling through the week. It is worth noting that another weather
system will be bringing precipitation chance back to the region,
thus there is a possibility for additional rises or a slowdown in
the fall of river levels.
Red River and Wild Rice at Abercrombie: The Red River is expected to
continue slowly falling this week at Halstad. All other Red River
locations will see rises in response to the snow melt from last
weeks winter storm. Secondary crests are expected from Wahpeton to
Fargo, then in East Grand Forks. Oslo will see a very slow fall
through the week with river levels only falling about half a foot
over the next 7 days. Further north, crests have not yet been
reached and river levels will continue to rise through weeks end.
Additional water contribution from expected rainfall this week could
cause additional rises across the area, especially for the southern
Red River Valley.
Areal and river point flood warnings continue across portions of
the region. Refer to the latest flood warnings and statements for
detailed information on specific locations.
Area Forecast Discussion
National Weather Service Grand Rapids MI
1102 PM EDT Sun Apr 14 2019
Issued at 326 PM EDT Sun Apr 14 2019
- Snow will continue tonight...heaviest northwest of a South Haven
to Alma line.
- Sunny Monday.
- Thunderstorms likely Thursday, some potentially strong.
Issued at 1100 PM EDT Sun Apr 14 2019
Deformation zone snow is hanging tough with occasional flare ups
of heavier intensities still being seen on radar. Latest HRRR
guidance still shows snow pulling away after 06Z and ending late
tonight, so additional accumulation should be generally an inch or
less. However with temperatures falling below freezing overnight
hazardous travel conditions may continue through the morning
commute despite the snow being over.
UPDATE Issued at 541 PM EDT Sun Apr 14 2019
Based on snowfall reports and the 88D precip/snow accumulation
algorithm, a band of rather heavy snow accumulations in excess of
6 inches has set up this afternoon from the Muskegon/Whitehall
areas, northeast across Newaygo and White Cloud, to Big Rapids
and Stanwood, and up toward Clare.
Muskegon has reported 2 inch per hour snows in their ob, and the
concern moving forward this evening with still more snow to fall
and northeast winds gusting to 25 mph is that the power outage
potential will be increasing over the next few hours within this
Just in the last hour or so the Consumers Energy outage map shows
outages increasing in Muskegon and Newaygo counties.
Fortunately, per latest short term model guidance, the heaviest
snows should be exiting to the northeast in the next couple hours,
followed by generally lighter snowfall rates after 00Z.
.DISCUSSION...(This evening through next Sunday)
Issued at 326 PM EDT Sun Apr 14 2019
A moderate band of snow stretches from north of STL across the
central CWA to Saginaw Bay. Mixed rain and snow is falling over the
southern cwa. An inch or so of really wet slushy snow has created
hazardous driving conditions with many accidents reported on area
highways. The snow is going to continue through midnight or so as
low pressure moves across the Ohio Valley. Additional accumulations
of an inch or two are possible after 00z, even over the southern cwa
where the rain will turn to snow toward evening.
A warm front moving north Tuesday will generate some light rain
which may mix with freezing rain and/or snow over the northeast cwa.
This precipitation will linger into Wednesday as the warm front
becomes nearly stationary.
The main weather story for the week, though, is the potential for a
strong low to develop over western Wisconsin. There are a lot of
dynamics with this storm such as a strong accompanying short wave,
50kt llj, and strong shear. Instability has been a limiting factor
recently as thunderstorms tried to develop, but it may not be
Thursday. After the stationary boundary lifts north as a warm front,
Li`s fall to -2c and surfaced based cape rises to around 500 j/kg as
the trailing cold front moves east during peak heating. Given strong
inflow of moisture from the Gulf and we may see an abundance of
thunderstorm activity Thursday afternoon and a few of the storms
could be strong and perhaps severe across the southern cwa.
The ecmwf/gfs show the low lingering over Michigan through Saturday
so light rain showers look possible.
.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 802 PM EDT Sun Apr 14 2019
Widespread IFR and icing threat continuing this evening, with
areas of LIFR vsbys in snow/heavy snow around MKG and GRR.
Precipitation is still mostly rain south and east of GRR, but
expected to mix with and change to snow shortly before ending
later this evening. IFR conditions giving way VFR early Monday
from northwest to southeast. North-northeast winds 15-25 kts
becoming northwest and diminishing to around 10 kts overnight.
Issued at 326 PM EDT Sun Apr 14 2019
The gale warning will expire at 00z for the southern marine zone. A
small craft advisory will be in effect for the entire nearshore
through 12z Monday and for the southern 3 zones through mid day due
to higher waves.
MI...Winter Weather Advisory until 4 AM EDT Monday for MIZ037>040-
LM...Small Craft Advisory until 8 AM EDT Monday for LMZ847>849.
Small Craft Advisory until 2 PM EDT Monday for LMZ844>846.
Area Forecast Discussion
National Weather Service Greenville-Spartanburg SC
827 PM EDT Sun Apr 14 2019
A strong system will bring more widespread storms to the area on
this afternoon and tonight, with severe weather possible. Dry
weather conditions will prevail through mid-week, with showers and
thunderstorms returning at the end of the week with an approaching
.NEAR TERM /THROUGH MONDAY/...
As of 800 PM...Have allowed Tornado Watch #62 to expire over our NC
PIedmont. Meanwhile, a line of tstms along a sfc cold front
continues to slowly cross the western third of the FA within Severe
Tstm Watch #66. That watch was expanded a little east across the
rest of our NE GA zones and also Anderson and Greenville counties in
SC. The latest HRRR hints that an uptick in the convection is likely
over the next 2-3 hours, thus the watch expansion. From there,
instability should really start to decrease, and the low-level jet
max seems to be racing east ahead of the slow-moving convective
line. With that said, cannot rule out another Severe Tstm Watch at
02z (10 PM), if the convection continues to look robust. Otherwise,
the wind headlines look okay. Not seeing as many gusts in the 35-40
kt range as earlier, but plan to let the headlines ride. PoPs are
lining up well with the convection so far.
The front should clear the area to the east by around 06z. Gusty NW
winds and rapidly dropping temps expected behind the front in the
high terrain late overnight. Strong gradient winds along and
immediately behind the front will continue especially across the
mountains, but will let the High Wind Warning expire at 02z. Gap
winds overnight coming off the higher elevations may lead to some
minor wind concerns in the Piedmont. Moisture and CAA may result in
some light snow at the higher elevations, but not enough for an
advisory of any sort. Much cooler tonight behind the front, a good
20 degrees cooler than this morning`s lows, and freezing in the
mountains (frost/freeze program not turned on up there). Strong CAA
will result in highs 5-10 degrees below normal on Monday, breezy
.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/...
As of 215 PM EDT Sunday: Ridging aloft and high pressure near the
surface will provide quiet weather with mostly clear skies and light
winds through the short term, Monday night through Wednesday
evening. Surface high pressure over the region Monday night will
likely support below normal lows in the mid 30s to mid 40s, warming
nicely into the upper 50s (mtns) to 60s to near 70 east of the mtns
Tuesday under nearly full April sunshine. Surface high pressure
pushing off the east coast will allow weak southerly return flow
Tuesday night into Wednesday. This along with high clouds possibly
streaming through the region will support lows in the mid 40s to
possibly mid 50s by early Wednesday morning rising well into the 70s
and possibly near 80 (depending on amt of high clouds) Wednesday
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
As of 220 PM EDT Sunday: ...From previous discussion due to
ongoing severe weather... Latest guidance continues to come into
better agreement on the timing of another approaching cold front
towards end of the work week. Per latest guidance, with sfc high
pressure offshore, sfc low over the central Plains will continue to
strengthen as it very slowly propagates northeastward towards the
Upper Midwest through into Friday. Aloft, southern stream trough
will strengthen and deepen as it shifts eastward, joining the
northern wave energy and becoming an upper closed low. Nearly
expanding across most of the CONUS, the center of this feature will
eject into the upper Midwest into Friday night, while at the sfc,
the parent low`s cold front will already be in the process of
pushing eastward through the FA in the morning hours. Given how far
out this feature is, there`s still plenty of time for temporal and
spatial changes, but overall anticipate shower and thunderstorm
chances to return as early as Thursday. Ahead of the front where the
Southeast will once again be well in the warm sector, it`ll be
another Spring-like system on tap for the last weekend in April,
with dewpoints nearing 60 degrees and high temperatures on Thursday
ranging from the mid 70s to near 80 degrees south of the I-85
corridor and in and around the Charlotte Metro area. Behind the
exiting system, upper troughing will linger and swing overhead
Saturday and Saturday night, with lingering precip along the TN
border possible, where elsewhere, a drying trend will be already
occurring. Though temperatures will drop to below normal behind the
exiting front, do anticipate temperatures attm to remain above
freezing in the mountains, thus do not anticipate any mention of
.AVIATION /01Z MONDAY THROUGH FRIDAY/...
At KCLT and elsewhere: Main concern is timing line of slow-moving
convection still west of the Upstate TAF sites at time of 00z TAF
issuance. The latest high-res models seem to be initializing this
well, and so the timing of tempo groups for TSRA is based mostly on
them. Not as confident how well the activity will hold up by the
time it reaches CLT, but will keep a tempo for the 03-05z time frame
for now. Once the front pushes thru to the east, winds will shift to
SW, then WNW Monday morning. Winds will be gusty thru the evening,
with some lull possible overnight, then becoming gusty again late
Monday morning (although not as strong as earlier today). Skies
should clear out, with some stratocu banking up against the western
slopes of the mountains, which are not expected to reach KAVL.
Outlook: VFR conditions will continue through mid-week. The next
cold front bringing moisture and potentially strong storms will
approach the area late Thursday thru Friday.
00-06Z 06-12Z 12-18Z 18-00Z
KCLT High 91% High 100% High 100% High 100%
KGSP High 93% High 100% High 100% High 100%
KAVL High 89% High 100% High 100% High 100%
KHKY High 89% High 100% High 100% High 100%
KGMU High 96% High 100% High 100% High 100%
KAND High 98% High 100% High 100% High 100%
The percentage reflects the number of guidance members agreeing
with the scheduled TAF issuance flight rule category. Complete hourly
experimental aviation forecast consistency tables and ensemble forecasts
are available at the following link:
GA...Wind Advisory until 10 PM EDT this evening for GAZ010-017-018-
NC...Wind Advisory until 10 PM EDT this evening for NCZ033-035>037-
High Wind Warning until 10 PM EDT this evening for NCZ033-
SC...Wind Advisory until 10 PM EDT this evening for SCZ001>014-019.
Area Forecast Discussion
National Weather Service Wilmington NC
1039 PM EDT Sun Apr 14 2019
A cold front accompanied with showers and a few thunderstorms
will clear the Carolina coasts late in the pre-dawn Mon hrs by
before daybreak. Dry high pressure will follow and build across
the area late Monday through the midweek period. The next cold
front will slowly cross the Carolinas late this week or early
Sat with a round of showers and thunderstorms possible. High
pressure will follow and build in from the southwest late next
weekend thru early next week.
.NEAR TERM /THROUGH MONDAY NIGHT/...
As of 1005 PM Sunday...The Tor Watch has been cancelled. Tstorm
Kinematics are quite engaging but unfortunately the instability
is lagging. Some additional dynamics are progged to push across
the FA overnight, but will it be enough to overcome and work
with what little instability remains given the low level SE-S
flow from off the Atlantic the past few days. There may be
enough elevated instability to work with as that next area/line
of convection and associated dynamics pushes east. Nevertheless,
still agree showers and a few storms will be possible during
the pre-dawn Mon hrs and thus will not completely lower POPs.
The latest HRRR and HiResW continue their increased coverage re-
intensification of tstorms overnight but just downstream and
east of the ILM CWA and waters. Have "re-done Pops and Wx
for late this evening and overnight and have also tweaked
overnite min temps by a degree or 2 at most.
As of 700 PM Sunday...TOR Watch in effect for the entire land
based ILM CWA thru 06Z. Based on latest 88d trends and HRRR
model runs, POPs and WX have also been updated to account for
the best chances and locations to experience T and especially
T+ during the TOR Watch period ending at 06Z. The earlier thick
Cirrus overcast and the low level SE to S flow (ie. Maritime
Stable Atlantic Air) of the past 1 to 2 days, have combined to
limit instability across the FA. Basically it`s a Low Cape
and High Shear Environment with discrete cells with Tornadic
signature type storms being favorable, hence the Tor Watch in
effect. Once the influence from this low level stable maritime
air is overcome somewhat from additional upstream dynamics, an
increase in tstorm coverage should fire up with models hinting
this possibly occurring during the pre-dawn Mon hrs, possibly
after 06Z. At and after 06z, the majority of this convection
should be downstream of the ILM CWA. With HRRR and HiResW
indicating this possibility.
As of 300 PM Sunday...An approaching cold front will move
through the area tonight preceded by scattered showers and
thunderstorms. A few storms could become severe with the
potential for damaging winds and large hail. The rain will taper
off from west to east overnight and should come to an end
completely by about daybreak Monday. Clearing skies and cooler
weather is on tap for Monday and Monday night. Minimums tonight
should fall to the upper 50s to lower 60s. Temperatures won`t
rebound a lot on Monday with highs expected to reach the upper
60s to lower 70s. Mins Monday night will fall the the mid 40s to
.SHORT TERM /TUESDAY THROUGH TUESDAY NIGHT/...
As of 300 PM Sunday...High pressure overhead on Tuesday, will
shift off the coast overnight. Mid to upper ridge will be
aligned up through the Southeast with plenty of dry air and
subsidence to keep a rain-free forecast. Light and variable
winds will come around to the S as return flow develops around
the high. The cooler air mass in place will modify with the
warmer and more humid air making its way in Tues night into Wed.
Dewpoint temps in the 30s Tues aftn will end closer to 50 by
Wed morning. Overall, expect dry weather with just below normal
temps and plenty of sunshine, making it feel warmer in the sun
and cooler in the shade on Tues. Temps should reach into the
lower 70s most places on Tues and fall into the low to mid 50s
.LONG TERM /WEDNESDAY THROUGH SUNDAY/...
As of 300 PM Sunday...Air mass will warm and moisten in
southerly return flow around exiting high pressure Wed into
Thurs. This will introduce aftn cu and only a very low end chc
of a localized shower on Thurs as ridge holds overhead most of
the day. Overall, expect cirrus to filter out the full sunshine
and some flat cu developing.
Moisture will increase further on Fri as air mass destabilizes
in warm and humid air mass ahead of front. This cold front will
march across the Carolinas Fri into Fri night. Southerly winds
will begin to increase as gradient tightens as early as Thurs
eve. Expect fairly widespread clouds and decent coverage of
shwrs and thunderstorms through Fri and could see some strong to
severe thunderstorms. Cold front moves off the coast with drier
and relatively cooler air moving in through Saturday, but deep
mid to upper trough still remains west of the area. As this
shifts east later on Sat, clouds and a chc of shwr will return
with dry air to follow for Sunday as high pressure builds in.
Temps will warm into the 80s most places Wed through Fri with
overnight lows on the warm side, remaining in the 60s. Temps
will begin to cool on Sat, back below normal but will warm again
on Sun in bright sunshine.
.AVIATION /02Z MONDAY THROUGH FRIDAY/...
As of 0Z....Currently MVFR ceilings at coastal terminals (with occasional
IFR at MYR and CRE) and VFR inland. Scattered storms across our area
tonight before main line of precipitation moves across shortly after
midnight with cold front passage. Chance for thunderstorms, and slight
chance some storms may become severe. Non-convective low level wind
shear is likely at coastal terminals between 2z and 7z, with southerly
winds at 2000 ft approaching 50kts. After cold front passage, skies will
clear out and remain clear for rest of TAF period. Strong southerly
surface winds overnight will veer to westerlies by late tomorrow
Extended Outlook...VFR through Thursday. Showers possible Friday.
As of 1015 PM Sunday...SCA for all waters continues. Have
maintained the changes made to winds/seas from the prior update.
The changes for this update are primarily to the POPs and
associated Wx for the remainder of the this evening thru the
overnight across the area waters.
As of 715 PM Sunday...The stable low level maritime Atlantic
air will keep convection from becoming too widespread as well
as reaching or surpassing SVR thresholds. For that reasoning,
the TOR Watch does NOT include the local ILM waters. Have
continued the SCA overnight thru much of Mon as the sfc pg
continues to tighten ahead of the cold front, with it`s passage
slated before daybreak Mon. S to SW 15 to 25 kt G30 will veer to
the West after FROPA and further veer to the NW Mon afternoon.
With CAA added to the mix, the waters will see a bit more
gustiness in the wind field.
As of 300 PM Sunday...Frisky conditions are expected over the
waters tonight with SW winds of 20 to 25 KT with higher gusts.
Isolated to scattered thunderstorms may produce locally higher
winds and waves. Winds will shift to the west shortly after
daybreak Monday and become NW toward evening before becoming
northerly late Monday night. Speeds will diminish from 20 to 25
KT Monday morning to 10 to 15 KT late Monday night. Seas will
build to 6 to 9 feet overnight tonight before subsiding to 3 to
5 FT by late Monday night.
High pressure will move overhead on Tue then shift offshore Tue
night. Offshore flow at the start of the period will gradually
weaken with winds veering from north to east Tue. Reduction in
wind speeds will allow seas to fall from 3 to 4 ft Mon night to
2 to 3 ft Tue and 2 ft or less Tue night. South to southwest
flow Wed and Thu with high off the Southeast coast. Gradient
will keep speeds 10 kt or less through early Thu with seas 2 ft
or less Wed, but increasing to 2 to 4 ft through Thurs aftn as
gradient begins to tighten with approach of cold front. Expect
a further increase in winds and seas Thu night into Fri with
SCA conditions developing around daybreak on Fri. Seas may
reach up to 8 to 10 ft in the outer waters by Fri night in
stiff southerly flow up 20 to 30 kts.
NC...Beach Hazards Statement from 6 AM EDT Monday through Monday
evening for NCZ110.
MARINE...Small Craft Advisory until 5 PM EDT Monday for AMZ250-252-254-
Area Forecast Discussion
National Weather Service Key West FL
1013 PM EDT Sun Apr 14 2019
.CURRENTLY...(Through Late Evening)
Mostly clear skies and warm, muggy conditions exist over the
Florida Keys right now, with temperatures in the lower 80s at 10
pm, and dewpoints in the mid 70s.
Satellite imagery and surface obs nicely depict a cold front
trailing from the Big Bend of Florida down to the Yucatan
Peninsula, with upper level support provided by the upper trough
extending south from the Great Lakes region.
A few showers are currently developing over our far western waters
west and south of the Dry Tortugas. However, the 00z KEY sounding
shows a dry and stable layer between about 4,000 and 8,000 feet,
which will inhibit showers from reaching the Lower Keys until very
late tonight. Indeed, the last two runs of the HRRR have changed
their tune by now keeping these showers away from the Lower Keys
late this evening. So does the 18z NAM. Will be counting on this
initial wave of showers to dissipate about the time they move east
to Rebecca Shoal or the Marquesas Keys.
.SHORT TERM...(Late tonight through Tuesday night)
Upper level support will outrun the cold front over the Gulf late
tonight and Monday. Will be relying on shallow lift created by
low-level convergence near the front to squeeze out any showers.
A few showers could move across the Keys starting as soon as the
pre-dawn hours on Monday. Any chance for showers will end as the
cold front pushes across the islands during the early afternoon.
Shallow lift should be insufficient for any lightning.
Once the front passes, northwest then north winds will develop and
become gusty on Monday PM over the Lower and Middle Keys, where
land-based gusts near 20 mph are expected.
The post-frontal air mass that passes by the Keys on Monday night
and Tuesday will not be substantially cooler, but it will be a
bit drier. Dewpoints will bottom out around sunrise on Tuesday
in the less muggy mid 60s. PW values will drop well under 1" until
Wednesday, which makes a dry forecast from Monday PM through
Wednesday virtually assured. After Tuesday morning, surface winds
will quickly become easterly, bringing a return of higher surface
dewpoints, though the depth of surface-based moisture will remain
shallow under a strong upper high.
.LONG TERM...(Wednesday through Sunday)
From Previous Discussion: A western North Atlantic ridge
extending across the Gulf coast States and the Sunshine State
will slowly shift south and southeastward, as a cold front moves
eastward in the Gulf of Mexico on Thursday into early Friday. With
that, moisture will be on the increase so isolated pops will be
inserted for the island chain beginning Wednesday night with
chance pops starting Thursday night. Thereafter, medium range
guidance and ensemble members differ somewhat on the exact timing
of the cold front clearing our region, so middle of the road
chance pops will be carried despite MOS guidance being higher
until certainty increases. For next weekend, it appears cooler and
drier air will prevail for our entire region. Stay tuned as
changes are likely.
Gentle to moderate southeast breezes this evening will clock
around out of the southwest and west near 10 knots well after
midnight. Winds will increase and clock around to northwest to
north on Monday afternoon following a cold front. Fresh north
breezes northwest of the Lower Keys will build significant wave
heights over the deep southeast Gulf waters as high as 6 feet on
Moderate to perhaps fresh north to northeast winds overspread
most of our marine district by early Tuesday morning. Moderate to
fresh winds with the higher winds on the Straits of Florida are
anticipated during the middle of this week.
A few layers of clouds between 020 and 080 will develop and
increase late this evening and overnight, in advance of a cold
front that will pass the terminals around 17z-19z on Mon. The
possibility of a weak shower peak around sunrise and is reflected
in the TAF with VCSH.
Following frontal passage, a sudden increase in north wind will
occur, posing cross-wind issues on the east-west runways at EYW
and MTH. Northerly gusts of 15-19 knots appear most likely on
Monday PM. Skies will also clear out following front passage.
In 1940, the daily record low temperature of 58 degrees was
recorded in Key West. Temperature records date back to 1872.
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Updated for 00Z Aviation Forecast Discussion below.
.PREV DISCUSSION... /issued 322 PM CDT Sun Apr 14 2019/
DISCUSSION...Surface analysis this afternoon places a surface low
over Southwest Ohio with a trailing cold front over East Tennessee
then back through Alabama and the Florida Panhandle. Cloudy skies
persist over the Mid-South this afternoon as GOES-16 satellite
trends still indicate an upper level low gradually rotating
through the Middle and Lower Mississippi Valleys. KNQA WSR-88D
radar trends along with area observations suggest some light rain
showers or sprinkles occurring across portions of West Tennessee
as of discussion. As of 3 PM CDT, temperatures across the Mid-
South are predominantly in the 40s at most locations with a few
lower 50 degree observations near the MS/AL border.
Clouds should begin to decrease across the forecast area tonight
as the upper level low pushes away from the Mid-South into the
Ohio and Tennessee Valleys. Clearing skies combined with light to
nearly calm winds along with temperatures dropping into the
middle 30s with decent radiational cooling is expected to be
conductive for the formation of frost tonight, predominantly
across West Tennessee. Consequently, I`ve issued a Frost Advisory
across the above mentioned area.
Rain free weather is expected to persist across the Mid-South
through Tuesday with temperatures averaging slightly below normal.
Long term models continue to indicate an upper level trough moving
through the Central/Southern Plains into the Middle/Lower
Mississippi Valleys Wednesday night into Thursday. The potential
for strong to severe thunderstorms still look possible during this
timeframe and have left mention in the Hazardous Weather Outlook.
This will continue to be monitored in subsequent forecasts with
potential threats being mentioned as this potential event draws
closer. Stay tuned...
Some wrap around moisture associated with the upper level trough
axis will bring a chance of rain showers for Friday into Saturday
along with a return of slightly below normal temperatures.
Broken high MVFR ceilings will give way to clear skies as thermal
trof around FL050 lifts east this evening, and surface temps
A surface pressure ridge center will track east across southern
MS overnight, with an inverted ridge axis extending north through
the Midsouth. Under clear skies, expect calm surface winds for
at least part of the overnight. Short range guidance from the
HRRR suggests no fog, but MKL NAM Bufr sounding shows some
potential for fog. Given saturated soils, climatology suggest at
least a chance of MVFR VSBY developing at MKL and perhaps TUP.
TN...Frost Advisory from 1 AM to 8 AM CDT Monday for Benton TN-