Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 04/13/17
Area Forecast Discussion
National Weather Service Columbia SC
926 PM EDT Wed Apr 12 2017
.SYNOPSIS...
A weak cold front in the forecast area tonight will be diffuse and
just south of the area Thursday. High pressure moving into the
Northeast States will ridge southward and into the forecast area
Friday. The high will continue to dominate over the weekend as it
slides southeastward to a position off the Southeast Coast Sunday.
Another cold front approaching from the northwest will be near the
area Monday supporting a chance of showers and thunderstorms.
&&
.NEAR TERM /THROUGH THURSDAY/...
The evening isolated showers and thunderstorms were hindered
because of the dry air near the surface and in the mid levels.
Nocturnal cooling has helped cause dissipation. The high-
resolution models indicated increased low-level convergence in
the piedmont late tonight associated with the interaction of the
weak front and well inland protrusion of the sea breeze front,
but additional development will probably not occur because of
nocturnal cooling and lift ahead of the upper trough shifting
east of the area. The HRRR did not indicate additional showers.
The temperature forecast was on track and expect lows in the
middle and upper 50s. Cooling and light wind may lead to fog
toward sunrise but because of the dry near-surface layer expect
any fog would be mainly confined near bodies of water and the
few locations that had rain during the afternoon or evening. The
SREF indicated low fog probabilities. The NAM and GFS MOS
confined fog mainly to the river valley sites of AGS and OGB.
Forecasted just patchy fog during the early morning hours.
&&
.SHORT TERM /THURSDAY NIGHT THROUGH FRIDAY NIGHT/...
A weak cold front will drop south and east of the area Thursday
morning, with veering winds through the day as high pressure
builds from the Mid-Atlantic coast. As the low-level flow
becomes more northeasterly late in the morning and during the
afternoon, moisture will begin to advect into the region from
the Atlantic. Weak surface convergence, mainly in the vicinity
of the eastern Midlands and lower CSRA, could support isolated
to perhaps scattered showers/thunderstorms from late morning
through the afternoon in those areas. The northeasterly flow and
added cloud cover during the day should keep temperatures from
rising much above the upper 70s or lower 80s.
Any lingering showers/thunderstorms into Thursday evening will
quickly dissipate with the loss of daytime heating. Clearing
skies, light winds and some left over low-level moisture could
result in some patchy fog late Thursday night. Lows will be in
the 50s across the area.
For Friday and Friday night, strong upper-level ridging will
build over the area from the northern Gulf Coast region as
surface high pressure shifts into the western Atlantic. Strong
subsidence and limited moisture will result in a abundant
sunshine during the day and mainly clear skies at night. Highs
will generally remain in the upper 70s to lower 80s, with
nighttime lows in the 50s.
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
The upper-level ridge will shift across the Florida Peninsula
Saturday, with some weak short wave energy rounding the top of
the ridge and passing across the area. Meanwhile, surface high
pressure over the western Atlantic will allow for a
southeasterly/onshore flow, which will not only increase low-
level moisture but should allow the seabreeze to penetrate into
the eastern Midlands. The GFS continues to indicate the
potential for isolated showers across the eastern Midlands, but
with little support from the other models. While an isolated
shower seems possible, will take mention out of forecast as
coverage will be very limited. Certainly expect an enhanced
cumulus field however.
Dry weather will prevail through Easter Sunday with deep layered
ridging continuing to build into the region from the western
Atlantic. The ridging breaks down Monday as a backdoor cold
front approaches from the north, and eventually shifts into the
area Monday night into Tuesday. The front then appears to lift
back to the north as a warm front Wednesday. Given the presence
of the front, most of the first half of next week appears to be
unsettled, with a 20-40 percent chance of showers and
thunderstorms in the forecast from Monday through Wednesday.
Temperatures through the long-term period appear to remain
slightly above normal.
&&
.AVIATION /02Z THURSDAY THROUGH MONDAY/...
VFR conditions expected through most of the TAF period. Visibility
restrictions possible, mainly at AGS/OGB late tonight/early Thursday
morning.
A weakening surface front will move slowly into the forecast area
tonight, and stall just to our south Thursday. With limited moisture
to work with, there is only a slight chance of showers and
thunderstorms at the TAF sites through early this evening, and again
tomorrow afternoon.
The upper-level trough will move east of the area late tonight,
with clearing of high-level cloudiness expected. However, some
low- to mid-level cloud cover could linger. Because of
uncertainties with regard to cloud cover, and possibly some wind
just behind the frontal boundary, will indicate fog mainly at
the fog prone sites, AGS and OGB.
EXTENDED AVIATION OUTLOOK...Late night/early morning fog/stratus
possible through Saturday.
&&
.CAE WATCHES/WARNINGS/ADVISORIES...
GA...None.
SC...None.
&&
$$
SYNOPSIS...99
NEAR TERM...99
SHORT TERM...99
LONG TERM...99
AVIATION...99
Area Forecast Discussion
National Weather Service Dodge City KS
732 PM CDT Wed Apr 12 2017
...UPDATE TO SYNOPSIS...
.SYNOPSIS...
Issued at 730 PM CDT Wed Apr 12 2017
WV imagery indicates a weak upper level shortwave trough of low
pressure moving eastward across the Desert Southwest. Near the
surface, a near stationary frontal boundary extends from southeast
Colorado northeast into north central Kansas. A line of strong
thunderstorms extends near and along the frontal boundary across
much of western Kansas with some storms producing very heavy
rainfall.
&&
.SHORT TERM...(This evening through Thursday)
Issued at 154 PM CDT Wed Apr 12 2017
There will be a chance for thunderstorms late this afternoon and
early this evening along a surface boundary that will be located
from east central Colorado border to north central Kansas. RAP
and NAM both indicated an inverted V model sounding east of this
boundary at 21z Wednesday and 00z Thursday with CAPE values in
excess of 2000 j/kg. 0-6km shear was forecast to be around 30
knots across southwest Kansas and around 35 knots further north
closer to the Nebraska border. Organized multicells appears to be
the storm mode for early in this event. Also based on the models
soundings the main hazard from developing thunderstorms late today
and early this evening will be wind gusts up to 60 mph. Hail will
also be possible with hail sized mainly one inch or less. Once
developed these storms are expected to move easterly based on the
700mb to 300mb mean winds but as they exit the instability axis
and with the loss of heating this evening these storms are
expected to weaken. Areas north and west of Dodge City this late
today will have the better chance for this scattered convection
with the area favoring the strong winds being west of a Dighton to
Ulysses line.
Models remain in good agreement on a negatively tilted upper level
trough lifting northeast across western Kansas on Thursday. As
this system approaches late tonight and early Thursday the chance
for rain showers will return. This will provide the best chance
for precipitation across south central and portions of western
Kansas. Main concern today is how far west the precipitation will
spread during the day on Thursday. At this time am currently
favoring keeping the better chances for precipitation east of the
700mb to 500mb deformation zone west northwest of the upper
low/trough. Areas that do get this extended period of steadier
rain on Thursday/Thursday night could easily receive anywhere from
1/2 to around 1 inch.
.LONG TERM...(Thursday night through Wednesday)
Issued at 154 PM CDT Wed Apr 12 2017
The ongoing precipitation across western Kansas will taper off
Thursday night as the negatively tilted upper level trough lifts
northeast into eastern Nebraska. A surface boundary, extending
west to northeast across western Kansas at 00z Friday, will lift
northeast as a warm front Thursday night which will shift the
winds from the southeast to a more southerly direction. Low clouds
along with some fog is expected Thursday night but the
combination of a more southerly wind and low level winds speeds
increasing late night confidence is not high for dense fog
developing. The area more favorable for fog and possibly even some
drizzle Friday morning will be in north central Kansas based on
the moisture profiles from the NAM.
Gusty south to southeast winds will develop early Friday as
surface pressure falls along the lee of the Rockies as another
upper level trough approaches from the west. Based on the moisture
return and 0-1km moisture convergence along a surface boundary
there may be a few isolated late day/evening thunderstorms near
the Colorado border but given the warm mid temperatures around the
700mb level the probability appears very low.
Temperatures on Friday should warm up nicely given the expected
mixing depth and mix down temperatures at that level. Highs 80 to
85 still looks on track...could even be a little warmer in far
western Kansas.
A better chance for convection will occur on Saturday as a cold
front crosses western Kansas. A few strong or even severe
thunderstorms will be possible late day along this frontal
boundary as it crosses south central Kansas late Saturday
afternoon/early Saturday evening.
Cooler, more seasonal, temperatures will return to western Kansas
on Sunday as a surface ridge axis crosses the Central Plains and
a cold front stalls out across the Texas Panhandle and Oklahoma.
What little sun that does develop early Sunday will give way to
increase clouds and possibly even some precipitation will develop
late day as moisture and lift improves north of the surface
boundary in northern Oklahoma. Based on the moisture and
isentropic lift in the 295 to 305 levels along with the 850mb warm
air advection the area more favorable for this precipitation will
be south of the Arkansas river from late Sunday through early
Monday. Current Highs forecast Sunday in the 65 to 70 degree range
may be a little too warm given the expected Cloud cover and
probability of precipitation.
A warming trend will begin early next week as a warm front lifts
north across southwest Kansas. Confidence is not high on how
quickly the cooler air will erode on Monday so although did not
stray far from guidance the highs of around 75 on Monday may be a
little to warm if the warm front is slowly to lift north.
&&
.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
Issued at 617 PM CDT Wed Apr 12 2017
Scattered thunderstorms will move eastward across central and
northern portions of southwest Kansas through late this evening,
potentially affecting KHYS, KGCK, and possibly KDDC with brief
MVFR vsbys due to heavy rainfall. Otherwise, VFR conditions are
expected to prevail at all TAF sites through late Thursday
morning. Although a surface low will remain anchored across
southeast Colorado tonight, southerly winds 20 to 30kt will
subside through late this evening with the loss of daytime
heating. Southerly winds are then expected to increase again
toward early Thursday afternoon as the surface low strengthens.
&&
.PRELIMINARY POINT TEMPS/POPS...
DDC 53 67 56 79 / 30 60 50 10
GCK 51 67 53 82 / 40 50 30 10
EHA 50 70 53 82 / 20 40 20 10
LBL 54 68 54 81 / 30 60 30 10
HYS 51 69 56 78 / 60 50 60 10
P28 56 70 58 77 / 30 70 70 20
&&
.DDC WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SYNOPSIS...JJohnson
SHORT TERM...Burgert
LONG TERM...Burgert
AVIATION...JJohnson
Area Forecast Discussion...CORRECTED
National Weather Service Quad Cities IA IL
648 PM CDT Wed Apr 12 2017
...AVIATION UPDATE...
.SYNOPSIS...
ISSUED AT 404 PM CDT Wed Apr 12 2017
GOES IR satellite imagery showed mainly clear skies through much of
the day give way to a mid-level overcast now entering eastern Iowa.
The mid-level clouds will overspread all of E Iowa/NW Illinois and
NE Missouri through the late afternoon and early evening. The
abundant sunshine caused sfc temps to rise into the 60s, and
combined with light winds, led to a very nice day.
An area of convection, with cloud tops colder than -60 C, was noted
over extreme NE Kansas. This region of thunderstorms was producing
cloud-to-ground lightning. Further north into Nebraska, an area
of convection has weakened to just showers within the last hour.
The shortwave trough responsible for these showers and
thunderstorms will impact the local region tonight.
&&
.SHORT TERM...(This Evening through Thursday)
ISSUED AT 404 PM CDT Wed Apr 12 2017
This Evening and Tonight:
A low amplitude mid-level wave will be strong enough to bring a
round of showers and thunderstorms through the CWA tonight into
early Thursday morning. Recent SPC mesoanalysis had a 850mb low-
level jet situated over Kansas and E Nebraska, pumping moisture
northeastward. Models move this feature to the ENE tonight,
placing the area of 925-850mb WAA and convergence over the
northern two-thirds of the CWA. The HRRR has trended slightly
further south with the heaviest rain which will occur toward the
southern edge of the complex of showers - in the overlap zone of
better instability but still sufficient forcing.
Expect a widespread 0.25 to 0.50 inches, and likely a focused
corridor of heavier amounts up to 0.75-1.00 inches. The one
exception is probably the far south/southwest sections of the
CWA. Here rainfall may be under 0.10 inches. Marginal shear and
instability will preclude any threat for severe weather.
Thursday:
Showers and embedded thunderstorms are forecast to decrease in
coverage as the low-level jet wanes. There is a low chance for
isolated showers and thunderstorms redeveloping near a sfc
boundary during the afternoon, mainly south of I-80. The main
story will be the large north-to-south temp gradient from the
upper 50s far north to the mid 70s far south. It could potentially
be colder across the north half of the CWA in a NE sfc flow under
overcast skies, but didn`t want to trend any colder due to some
model disagreement.
.LONG TERM...(Thursday Night through Wednesday)
ISSUED AT 404 PM CDT Wed Apr 12 2017
Thursday Night through Saturday Night:
Next shortwave trough to impact the Midwest. Low-level pressure
fields show a warm front lifting through the area on Friday,
followed by a cold front on Saturday. Expect periodic chances for
showers and thunderstorms. One concern is that a moist air mass
may result in areas of heavy rainfall. NAEFS PWATs exceeding 1.25
inches are 2-2.5 standard deviations above average for the middle
of April. However, the good news is the warm front is not forecast
to stall over the CWA on Friday. Also, the rain on Saturday will
be associated with a transient cold front, decreasing the threat
for excessive rainfall.
At this time, deep layer shear is not favorable for severe
weather.
Sunday and Monday:
High pressure and post-frontal air mass moves into the Midwest -
so drying out and pleasant for the end of the weekend/early next
week.
Tuesday and Wednesday:
Another trough approaches the area. Rounds of showers and storms
are likely, but may hold off until Tuesday night. Rises on area
rivers could become a concern during or after this round of rain.
&&
.AVIATION...(For the 00Z TAFS through 00Z Thursday Evening)
ISSUED AT 640 PM CDT Wed Apr 12 2017
Scattered showers ahead of an upper level disturbance may produce
sprinkles at CID, BRL and MLI in the evening. Overnight, another
round of showers is likely as a weak system sets up a frontal
boundary over southern Iowa. There is a low potential for
thunderstorms, which is no longer included in the terminal
forecasts. Conditions are expected to deteriorate to IFR due to
lowering ceilings as low clouds setup along and north of the
surface front. Ceilings are likely to lift to MVFR during the day
Thursday, but confidence is low in the timing.
&&
.DVN WATCHES/WARNINGS/ADVISORIES...
IA...NONE.
IL...NONE.
MO...NONE.
&&
$$
...corrected for formatting...
SYNOPSIS...Uttech
SHORT TERM...Uttech
LONG TERM...Uttech
AVIATION...Sheets
Area Forecast Discussion
National Weather Service Sioux Falls SD
1037 PM CDT Wed Apr 12 2017
.SHORT TERM...(This evening through Thursday)
Issued at 338 PM CDT Wed Apr 12 2017
Afternoon water vapor imagery shows strong signature of jet streak
diving into eastern SD this afternoon, with main lift currently
shifting into far northeastern CWA near KMML. At the surface, weak
low pressure centered over northern Nebraska with warm front
southeast toward I-80. Curiosity of the day has been the persistent
area of smoke which has streamed northward from eastern Kansas, and
has been caught up in convergence zone over heart of the CWA from
KYKN to KFSD and east into far northwest Iowa. Even with rainfall
passing through, the smoke persisted with the strengthening of the
inversion, which finally should start to mix and advect out as flow
turns more northeast at low levels.
With synoptic scale subsidence in wake of the passage of PV maximum
pushing into southwest MN, have a little doubt that more mesoscale
lift forcing in the lower- to mid-level warm advection across areas
near/east of I-29 very late afternoon into early evening will be
strong enough to overcome the larger scale subsidence component.
Presence of convection between I-80 and I-70 is not a positive
factor either, as will help to veer low-level winds as well. HRRR
and especially NAM have been quite bullish with redevelopment of
showers/isolated T across northwest Iowa during the early evening, and
actually showing a backing of this warm advection zone further
westward. Will maintain some modest chance PoPs over mainly
northwest Iowa into southwest MN through early evening, at least
until lingering low-level jet veers even further eastward.
Main issue heading forth after the ending of precipitation this
evening will be potential for stratus/fog with persistent
east/northeast surface flow through Thursday. At this point, a
fairly strong consensus for stratus to develop across parts of
southern MN and northern IA during the later evening, then spread
west and southwest across much of the area through Thursday morning.
Not sure how much would be fog vs. stratus, and have kept fog at
more patchy levels compared to a greater coverage of lower clouds,
which should reach a maximum sometime in the mid morning. While
models are fairly insistent that clouds will fully mix out by early
afternoon on Thursday, am more confident of this occurrence across
areas west of I-29 downstream of ridge axis, with some areas perhaps
lingering into a broken ceiling state much longer toward southwest
MN and northwest IA. There should at least be some sunshine in all
areas during the afternoon, and will help temperatures reach near 60
in cloudier eastern zones, and perhaps mid to upper 60s in the
Missouri River valley.
.LONG TERM...(Thursday night through Wednesday)
Issued at 338 PM CDT Wed Apr 12 2017
Models in better agreement today bringing a compact shortwave
through the CWA early Friday. Instability continues to look meager
with this system as it moves through, but will continue to indicate
a minimal thunderstorm risk. Subsidence behind this wave should keep
things at bay in the afternoon and early evening. With the LLJ
intensifying a bit after midnight, still anticipated renewed
convection along the stalled boundary early Saturday morning. Still
a questionable risk for a few strong storms early Saturday.
Drier air sweeping southeast should push the risk for convection
into Iowa by the afternoon hours. A very nice day is in store for
Sunday, with another cold front arriving Monday morning.
A very active pattern continues into next week, with a progressive
wave moving into the Northern Plains quickly by Tuesday morning.
Return flow and broad warm advection ahead of this wave could spark
an increasing elevated shower risk late Monday into Monday night,
with higher thunderstorms risks overnight into Tuesday morning as a
front sweeps through. Some considerable differences remain in
extended range guidance, more in the specifics than the general
pattern, so timing of rain chances is likely to change.
&&
.AVIATION...(For the 06Z TAFS through 06Z Thursday night)
Issued at 1022 PM CDT Wed Apr 12 2017
Main aviation concern overnight will be impending stratus and
fog. Northeasterly flow will cause stratus and fog currently
present across southwest Minnesota to spread across southeast
South Dakota and northwest Iowa. FSD and SUX will likely be
impacted. Left visibility or ceiling restrictions out of the HON
TAF due to lower confidence in stratus or fog reaching that
terminal. Conditions should recover by early afternoon Thursday.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...None.
MN...None.
IA...None.
NE...None.
&&
$$
SHORT TERM...Chapman
LONG TERM...Dux
AVIATION...Ferguson/JM
Area Forecast Discussion
National Weather Service Goodland KS
849 PM MDT Wed Apr 12 2017
.UPDATE...
Issued at 846 PM MDT Wed Apr 12 2017
Just completed an update. Per new model output and collaboration
with my neighbors, increased cloud cover over the western portion
of the area to account for the expected overnight stratus. Per
latest observational trends, made adjustments to the overnight
temperatures. Moisture, a little stronger winds, and cloud cover
will affect the southeast portion of the area first so increased
the lows there. Lighter winds and less cloud cover for longer will
make for cooler lows over the northwest half, and lowered those
temperatures. Current pops and development of overnight fog look
good and made little if any adjustments.
&&
.SHORT TERM...(This afternoon through Thursday)
Issued at 203 PM MDT Wed Apr 12 2017
Two distinct mid level shortwave troughs are splitting around our
CWA. A weaker ripple within the mid level flow may be moving over our
CWA based on RAP analysis (though this isn`t showing up in WV
imagery). WV shows dry/subsident air mass just northwest
spreading south and east. At the surface a weak cold front has
pushed into the far northwest part of our CWA, with a prefrontal
trough axis near Tribune extending just southeast of Hill City. A
CU field has developed along the area of covergence near this
surface trough in our southeast (mainly outside of our CWA).
This afternoon-evening: Latest mesoanalysis shows axis of ML cape in
the 10-1500 J/KG range along and south east of surface trough in our
SE CWA where CIN is beginning to weaken. High resolution models show
thunderstorm activity developing along this covergence zone/axis of
instability. Tendency will be for this activity to remain just
southeast of our CWA, but I can`t rule out this activity developing
just within our CWA. Better instability and shear would be east-
southeast, but there may be enough for an isolated/organized cell.
Based on near term convective allowing models this activity should
transition southeast of our CWA with mean flow and should end early
this evening.
Late tonight-Thursday morning: Low level flow shifts to the
southeast and will be responsible for increasing BL moisture and a
long fetch of upslope. BL winds may increase enough to limit dense
fog potential, however stratus and light fog are still possible.
This also complicates lows, and I could see a situation where parts
of our CWA do not drop out of the 50s if cloud cover fills in quick
enough this evening.
Thursday: A stronger negatively tilted mid level trough swings over
our CWA. Model soundings show PWATS just under 1" and strong forcing
combined with this moist air mass should support increasing shower
coverage across our east and the possibility for moderate rainfall
amounts Thursday afternoon. Track could limit potential with dry
slot/subsident region across our west. There should be enough
instability for embedded thunderstorms, maybe even a stronger storm.
I`m not particularly confident as in this as models show a fairly
high spread (possibly dependent on clearing skies. Best instability
on NAM is actually in subsident region. Models may be running high
for daytime temps if shower/thunderstorm coverage is better in the
east as consensus seems to indicate, so I trended highs down
slightly during this update.
.LONG TERM...(Thursday night through Wednesday)
Issued at 201 PM MDT Wed Apr 12 2017
The pattern remains active throughout the long term with multiple
disturbances passing near the area. Temperatures look to stay near
to above normal.
The first wave continues to move across the area Thursday night,
exiting Friday morning. With some instability and increasing
moisture, showers and thunderstorms are possible, mainly east of
the Colorado border.
Precipitation chances shift east of the region Friday morning.
However, another disturbance enters the High Plains from the west
and chances for showers and thunderstorms persist during the
afternoon and evening. A few strong to severe thunderstorms could
develop during this time, with the main threats as large hail and
damaging winds.
Dry weather is currently anticipated for most of the weekend. A cold
front pushes through on Saturday and southwesterly flow aloft turns
zonal. Precipitation chances return Sunday night into Monday when a
shortwave traverses the region.
Unsettled weather continues into next week as periodic shortwaves
move through the flow, generating on and off chances for showers and
thunderstorms. Will need to wait for better agreement among guidance
to nail down timing and locations impacted.
Temperatures peak at the start of the period with highs mainly in
the low 80s. A cold front pushes through on Saturday dropping
temperatures into the upper 60s/70s for the rest of the long term.
Lows will generally be in the 40s and 50s.
&&
.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
Issued at 522 PM MDT Wed Apr 12 2017
VFR conditions prevail through the first portion of the TAF period
for both sites. Winds will remain in the 5 to 8 kt range through
much of the night and into Thurs morning. Winds will gradually
shift easterly to southeasterly tonight, ushering in better
moisture values as we head into Thursday morning. This will allow
for potential fog and stratus development through the early
morning hours at both KGLD and KMCK. IFR to LIFR conditions could
become a possibility at KMCK with MVFR to IFR possible at KGLD
around or just after 12Z.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...NONE.
CO...NONE.
NE...NONE.
&&
$$
UPDATE...BULLER
SHORT TERM...DR
LONG TERM...JBH
AVIATION...TL
Area Forecast Discussion
National Weather Service Jacksonville FL
903 PM EDT Wed Apr 12 2017
.UPDATE...
Tonight...Weak High pressure ridge will linger at the surface
while a weakening upper level trof will cross the region and
produce a period of upper level clouds through the night but no
precip is expected. This trof axis, along with its clouds will
keep atmosphere mixed a bit and lessen the risk of fog towards the
morning hours and have removed the patchy fog from the current
forecast as latest HRRR forecast runs have removed any reductions
in visibilities across inland SE GA late tonight. Lows still
generally in the 50s inland and near 60 along the coast.
Thursday...High pressure will re-build just NE of the region over
the Carolinas and will send a NE surge of winds into the region
along with some Scattered to Broken Strato-Cu field off the Atlc
Ocean that will push across coastal areas in the morning and
spread across the rest of the inland areas with normal diurnal
heating. NE winds will be closer to 15G25 mph at the coast and
10-15G20 mph further inland with this renewed surge. Models still
show this new airmass too dry to support much in the way of any
shower activity, but it may shave a couple of degrees off Max
Temps compared to this afternoon with mid/upper 70s along the
coast and lower 80s further inland.
&&
.AVIATION...
Still another mainly VFR forecast. Overnight expect just mainly a
few high clouds with trof axis aloft, although strato-cu offshore
will start to come closer to the coast by morning. The NE surge of
winds is expected to push SCT-BKN strato-cu onshore during the
morning hours after 12z, and for now have advertised 3500 ft CIGS
but could be a brief MVFR CIG at the coast during the morning
hours. NE winds will increase to 12-14G20kts by the late morning
or early afternoon hours.
&&
.MARINE...
ENE winds at 10-15 knots will shift NE and increase slightly with
surge on Thu with some 15-20 knot speeds over the offshore waters
and SCEC headlines will be possible. Seas 2-4 ft tonight will
increase to 3-5 ft tomorrow.
Rip Currents: Moderate risk in the continuing onshore flow.
&&
.PRELIMINARY POINT TEMPS/POPS...
AMG 54 83 57 82 / 0 0 0 0
SSI 62 75 63 74 / 0 0 0 10
JAX 56 79 60 79 / 0 10 0 20
SGJ 61 76 64 76 / 0 0 0 30
GNV 55 81 57 82 / 0 0 0 20
OCF 56 82 57 83 / 0 0 0 10
&&
.JAX WATCHES/WARNINGS/ADVISORIES...
FL...None.
GA...None.
AM...None.
&&
$$
Hess/Nelson/Walker
Area Forecast Discussion
National Weather Service Chicago/Romeoville, IL
624 PM CDT Wed Apr 12 2017
.SHORT TERM...
225 PM CDT
Through Thursday...
High pressure will continue east as will the thin layer of cirrus
over much of the region. Winds will turn east across the forecast
area and increase to 10-15 MPH this evening. Cloud cover also
thickens ahead of the next system.
An upper level disturbance over the northern plains will move over
the region Thursday. Showers and isolated to scattered embedded
thunderstorms are expected early Thursday morning. Guidance still
differs widely on how quickly precip will spread east. The GFS,
ECMWF, and a couple of hi-res models have the quicker solutions that
bring precip through at least the I-55 corridor by 7AM CDT. Slower
solutions like the NAM and RAP only have the precip along and west
of a McHenry to Peru, IL line by 7AM CDT. I`m thinking it will take
time for the column to saturate tomorrow, so went with a slower
solution than the GFS and ECMWF, but still faster than the NAM and
RAP. While my confidence is high in showers, it is medium in
exact timing. I also have medium confidence in my thunderstorm
forecast. We`ll be working with minimal values of elevated CAPE so
I chose to keep a slight chance across the forecast area through
Thursday morning.
Precip shifts south and festers along a stationary boundary south
of I-80. Models have CAPE increasing near the front, but
soundings still only feature elevated CAPE so I kept thunder as a
slight chance.
While lows tonight will be about 10 degrees warmer than last night
away from the lake, cloud cover will limit warming tomorrow. Have
high temps ranging from the mid 50s along the IL/WI state line to
around 70 across the far southern portions of the forecast area.
Onshore flow will once again keep lakeside temps in the upper 40s.
JEE
&&
.LONG TERM...
225 PM CDT
Thursday night through Wednesday...
The period will begin Thursday night with low clouds and possibly
some showers across the area as a surface frontal boundary stalls
out over central Illinois and Indiana. Some modest isentropic
ascent is forecast to continue Thursday night along and north of
this frontal boundary, and this may continue to result in some
rain showers across portions of the area into Friday morning.
However, this frontal boundary is expected to shift back northward
across the area later Friday and Friday evening in response to a
decent mid-level short wave shifting over the Upper Mississippi
Valley and Western Great Lakes region. This feature is likely to
drive a better chance of showers and thunderstorms over the area
into Friday evening. Temperatures during the day will again be
much cooler along the lakefront in Illinois due to the onshore
flow, but temperatures may end up warming during the evening as
the surface warm front shifts the winds offshore.
Once the warm front shifts north of the area Friday night,
conditions look to become quiet warm and breezy across the region
in the warm sector Saturday. Temperatures at 925 MB are progged to
reach near 20 C, which could yield temperatures right around 80
degrees across portions of the area. Gusty southwest winds up
around 30 MPH during the day will also likely prevent lake breeze
development. Therefore, these very warm conditions are likely to
reach the lake front areas.
While conditions should be dry across the area Saturday, another
round of showers and thunderstorms is likely to impact the region
Saturday night into early Sunday morning, as a storm system
tracking over the Upper Midwest, drives a cold front across the
area. Cooler weather is likely to set up in the wake of this front
for early next week. This will especially be the case for areas
near Lake Michigan, where the presence of high pressure over the
Great Lakes region will favor persistent onshore flow early next
week.
The next chance of showers and thunderstorms looks to be
late Tuesday and Tuesday night, when another storm system looks to
impact the central portion of the country.
KJB
&&
.AVIATION...
For the 00Z TAFs...
624 pm...Forecast concerns include showers developing by sunrise
Thursday morning and cigs lowering into ifr Thursday morning and
possibly to lifr by Thursday evening.
Showers will spread across northern IL after midnight and short
term/hi res guidance has been speeding up the arrival time...
possibly in the 07z-08z time period at rfd and by 11z at the
Chicago terminals but further tweaks to timing can be expected
with later forecasts as trends emerge. These showers and maybe a
more prolonged period of rain will continue through late Thursday
morning...tapering off to drizzle in the afternoon. Limited
instability aloft should keep thunder chances isolated and also
mainly south of the terminals...so no mention with this forecast.
Mid clouds this evening will gradually lower through the night
and once precip arrives...mvfr cigs will develop. Only medium
confidence on how fast these mvfr cigs will lower but eventually...
they should lower into ifr by mid/late Thursday morning with ifr
cigs expected Thursday afternoon. Guidance suggests cigs could
lower further into lifr by Thursday evening... but low confidence
on cig trends that far out with this forecast. Winds will remain
generally easterly through the period around 10kts. cms
&&
.MARINE...
241 PM CDT
Easterly winds are expected to continue over much of Lake Michigan
through Friday as surface high pressure remains dominate over the
Upper Great Lakes and southern Canada. Wind speeds of 15 to 20 KT
are expected over southern Lake Michigan late tonight into
Thursday as the surface gradient tightens in response to a weather
disturbance moving across the area. These winds are likely to
result in waves building to 2 to 5 feet in the Illinois near
shore waters for Thursday. At the present, this appears to be
just below small craft advisory criteria, so we will hold off on
a headline.
A warm front is expected to shift northward over the lake Friday
night into Saturday. This will allow the winds to shift south-
southwesterly for Saturday. Given the strong gusty offshore winds
over Illinois and Indiana, wind speeds up to 30 KT may occur over
the southern Lake Michigan near shore waters. However, lighter
winds are expected over the open waters of the lake due to stable
conditions. A cold front is then expected to shift over the lake
Saturday night into Sunday. A period of showers and thunderstorms
is likely to accompany this front, followed by a westerly wind
shift.
KJB
&&
.LOT WATCHES/WARNINGS/ADVISORIES...
IL...None.
IN...None.
LM...None.
&&
$$
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Area Forecast Discussion...UPDATED
National Weather Service Memphis TN
933 PM CDT Wed Apr 12 2017
.UPDATE...
Other than scattered cirrus, skies were clear across the Midsouth
at midevening. With light winds and dewpoints in the 40s and 50s,
temps had cooled a little quicker than earlier forecast. Expect
temps to level off a bit during the overnight. In earlier
updates, have adjusted hourly trends and dropped overnight lows
slightly.
HRRR and SREF guidance suggest limited potential for overnight
fog, but could still see some reduced visibilities in river
valleys and near other bodies of water.
PWB
&&
.PREV DISCUSSION... /issued 652 PM CDT Wed Apr 12 2017/
UPDATE...
Updated for 00z Aviation Discussion.
DISCUSSION... /issued 311 PM CDT Wed Apr 12 2017/
Skies remain mostly sunny across much of the forecast area this
afternoon with temperatures mainly in the 70s. High pressure is
over lower Michigan this afternoon. The high will keep dry weather
and mild temperatures over the region tonight with lows Thursday
morning from the mid 50s to around 60 degrees. Thursday will be
another nice day with dry weather above normal temperatures with
highs in the upper 70s to lower 80s. Thursday night will be warm
and dry with lows Friday morning in the upper 50s to lower 60s.
Friday will see some isolated thunderstorms possible in the
afternoon hours. Temperatures will remain warm on Friday with
highs in the lower 80s. Dry weather will return for Friday night
and Saturday as temperatures remain above normal.
By Saturday night, a cold front will move across the central
plains and the Mid-Mississippi valley. Thunderstorms are expected
to form ahead of the front with some of this activity possibly
moving into northern sections of the forecast area. As the front
moves closer to the region on Sunday, there will be a better
chance of thunderstorms over the forecast area. The cold front
will move into the forecast area Sunday night and into north
Mississippi Monday morning. More thunderstorms are expected for
both periods.
The cold front stalls out over north Mississippi for Monday night
and Tuesday. This will mean there will still be a chance of
thunderstorms for both periods. By Tuesday night, the front will
start to lift slowly north as a warm front and will be just east
of the forecast area by next Wednesday. This will mean there will
still be a chance of thunderstorms for both Tuesday night and
Wednesday. Temperatures will remain a few degrees above normal for
the period from Monday through next Wednesday.
ARS
&&
.AVIATION...
00Z TAF set
VFR conditions expected at TAF sites through the period. Light
winds will become south winds around 5 kts on Thursday.
CJC
&&
.MEG WATCHES/WARNINGS/ADVISORIES...
AR...None.
MO...None.
MS...None.
TN...None.
&&
$$
Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
1051 PM CDT Wed Apr 12 2017
.SHORT TERM...(This evening through Thursday)
Issued at 340 PM CDT Wed Apr 12 2017
The short term concern is the overall extent of light rain showers
tonight into Thursday morning. Then the cloud/temperature trends
into Thursday.
Latest radar loop showing banded area of rain lifting east/northeast
across the cwa. It matches well with the isentropic forecast using
295K. We do like the latest HRRR handling the rain into the evening.
Looks similar to the overall 12z GFS trend. We will lift area with
its categorical/likely PoP east across the region mainly through 06z
Thu, then trend dry but remaining cloudy. Rainfall amounts should
remain generally one quarter inch or less as it moves through.
Clouds will likely linger into much of Thursday after some more fog
in the morning. Lower level boundary layer flow remains moist under
the influence of the surface ridge. Temperatures should remain in
the 50s much of the area once again...with a 60 degree reading out
west if clouds break up enough.
.LONG TERM...(Thursday night through Wednesday)
Issued at 340 PM CDT Wed Apr 12 2017
Confidence remains high that rain will fall at most locations on
Friday into Friday night. It also appears that precip will linger
through Saturday. Another storm system will bring showers and
possibly some thunderstorms across Minnesota and Wisconsin on
Tuesday, but there is considerable disagreement between the models.
Did not make any changes to the temperatures but did increase clouds
and winds on Sunday as it appears gusts near 30 mph are possible
during the afternoon with deep mixing and cold air advection.
Forecast models are in remarkable agreement with an upper level wave
developing over the Texas panhandle and lifting up through the
Midwest. This will lead to an area of showers and thunderstorms that
will overspread the region on Friday. GEFS has over 90% probability
of measurable precip, and no operational model is dry. Therefore
felt obligated to increase precip chances for late Friday despite
the timing and location difference with the heaviest QPF.
Southwest flow continues which support rising air and prolonged
period for rain as there is some low level convergence ahead of a
passing cold front. Forecast soundings show very little MUCAPE, so
do still have mention of thunder, but not anticipating any severe
weather, which agrees with the SPC outlook. Looking ahead, another
wave will bring precip across the region on Tuesday. The GFS 12.12
goes crazy and develops a deep surface cyclone, while the ECMWF and
GEM are more progressive with the wave. All the models do support
increased chances for showers and possible some thunderstorms, with
snow to the north of the low track.
&&
.AVIATION...(For the 06Z TAFS through 06Z Thursday night)
Issued at 1051 PM CDT Wed Apr 12 2017
The main concern overnight deals with the timing on low MVFR/IFR
ceilings and visibilities in the wake of the light rain this
evening. Confidence is highest for the lowest conditions at KAXN,
KRWF and KSTC, which are near the back edge of the clouds as well
as in conjunction with high levels of low level moisture. Further
east, VFR clouds are more extensive with low MVFR/IFR ceilings
developing late in the night. The visibility may not lower past
MVFR due to increasing wind associated with an inverted surface
trough developing across the area. The wind could also impact how
low visibilities go for the western terminals as well. Confidence
is decreasing on ceilings lifting to VFR Thursday afternoon
across WI and dropped them back to 025-030. Mainly east winds
less than 10 knots.
KMSP...MVFR ceilings and visibilities developing shortly after TAF
issuance with a period of ceilings below 010 still expected around
daybreak. Confidence is decreasing some on ceilings becoming VFR
Thursday afternoon but left them at BKN035 at this point.
/OUTLOOK FOR KMSP/
Fri...AM VFR. PM MVFR SHRA/TSRA. Wind SE 10-15 kts.
Sat...MVFR SHRA/TSRA likely. Wind SW 5 kts becoming NW.
Sun...VFR. Wind W 10-20 kts.
&&
.MPX WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
&&
$$
SHORT TERM...DWE
LONG TERM...JRB
AVIATION...RAH
Area Forecast Discussion
National Weather Service Pendleton OR
756 PM PDT Wed Apr 12 2017
.SHORT TERM...Tonight and Thursday...A moist southwest flow over the
forecast area this evening with widespread rain. This is all
occurring ahead of an approaching cold front that will sweep across
the forecast area late overnight and exit Thursday morning.
Precipitation will decrease west to east behind the cold front with
some increase of westerly winds. A cooler unstable airmass will move
in behind the cold front which will lead to instability showers
Thursday afternoon with the possibility of some thunderstorms
producing small hail.
&&
.PREV DISCUSSION... /issued 211 PM PDT Wed Apr 12 2017/
SHORT TERM...A low pressure system over the e pac will continue
to pump moisture into the two state area overnight. 5h/mb
divergence aloft should further enhance the shower activity that
is expected to expand in coverage and intensity into this evening
and some rivers may approach bankfull. A cool front is forecast
to race across the region tonight with some drier air to follow on
a westerly downslope wind over portions of the basin by Thursday
morning. Some rap around moisture will move into the region that
could become convective and produce an isold tsra mainly over the
eastern half of the region Thursday afternoon. Meanwhile another
wave of moisture will increase pops over our southern zones into
Thursday aftn/night. A further challenge will be lowering snow
levels and a few inches of snow is possible above 3k feet into
Friday morning especially over the blue/wallowa mtns. The bulk of
the moisture should drift away of the region and a weak ridge of
high pressure should build into the two state area Friday night.
LONG TERM...Saturday through Wednesday. Mainly dry conditions with
seasonal temperatures are expected Saturday and most of Sunday as a
ridge of high pressure moves through the region. A low pressure
system is expected to open and move across from south to north over
the area Sunday night through Monday with another round of showers.
A large area of low pressure will remain off the west coast through
the mid part of next week with several disturbances rotating around
the trough and will keep the showery conditions through much of next
week. Temperatures will be below normal through the weekend and
then moderate to near normal through the week. 93
AVIATION...00z Tafs. Mainly VFR conditions will continue through
Thursday with several rounds of showers moving through as a low
pressure area drifts north along the Washington/Oregon coast.
Heavier showers will cause periods of below VFR conditions at KYKM,
KDLS, KRDM and KBDN. Winds will be 10-15 kts. 93
&&
.PRELIMINARY POINT TEMPS/POPS...
PDT 45 57 38 52 / 100 40 40 30
ALW 47 59 41 54 / 100 40 40 40
PSC 46 61 41 58 / 100 20 20 20
YKM 44 60 36 57 / 100 20 20 20
HRI 45 60 40 57 / 100 20 20 20
ELN 41 55 36 52 / 100 20 20 20
RDM 35 51 27 49 / 90 50 40 20
LGD 44 53 34 47 / 100 70 80 50
GCD 41 51 32 46 / 100 40 60 40
DLS 45 58 41 56 / 100 20 30 20
&&
.PDT WATCHES/WARNINGS/ADVISORIES...
OR...None.
WA...None.
&&
$$
91/91/91
Area Forecast Discussion
National Weather Service Tampa Bay Ruskin FL
607 PM EDT Wed Apr 12 2017
.UPDATE (Overnight and Thursday)...
23Z water vapor and H4 RAP analysis shows a well-defined
mid/upper level shortwave evolving slowly eastward along
the northeast Gulf Coast this evening. Shortwave is a fairly
potent spin via NWP analysis...but does not extend any
lower than about 700mb...virtually undetectable at 850mb.
This impulse, despite its appearance from a abs vort/PV
perspective, is highly lacking in moisture and not
translating much influence into surface based sensible
weather. Seeing a few thunderstorms under the cooler core
aloft toward the western FL panhandle/southern Alabama, but
these should diminish with the setting of the sun and loss
of diurnal heating.
Closer to home...have seen a few speed convergence showers
over far south FL the past few hours within a zone of
slightly deeper moisture along and south of Lake
Okeechobee, but this activity has been struggling to reach
the I-75 corridor. Will likely still see a few brief showers
in Lee/Charlotte/Sarasota/Desoto/Highlands counties in the
next few hours...but this activity should be widely
scattered and brief for any locations lucky enough to see a
showers. Keeping overall rain chances on the low side and
will end all PoPs after 03Z.
During the overnight and early portion of
Thursday...shortwave aloft mentioned above will slowly pivot
to the southeast and over the FL peninsula while beginning
to shear out. Therefore, do not expect much if any impact
form this energy on our forecast. By Thursday
afternoon...the sheared out trough axis will be to our east,
followed by the arrival of a swath of NVA and further mid-
level drying. With this in mind...the potential for any late
day showers to the south of the I-4 corridor is even lower
on Thursday. North of the I-4 corridor the rain chances are
about zero.
Temperatures the next 24 hours will be seasonable. Winds
shift back offshore at the coast this evening and remain
from the east to northeast through the overnight/morning
hours of Thursday. Sea-breeze will struggle to move onshore
again on Thursday...with a wind shift to the northwest in
the afternoon limited to areas within a couple miles of the
coast.
&&
.AVIATION (12/23Z THROUGH 14/00Z)...
Prevailing VFR conditions with no significant aviation
concerns expected through the duration of the TAF period.
SCT-BKN clouds with bases between 5-8KFT this evening may
produce a brief shower for KPGD/KFMY/KRSW...but not
restrictions expected. Where winds have shifted onshore they
will shift back to the east by 01-03Z and remain from the
E/NE through Thursday morning. Sea-breeze will again make
limited inland penetration Thursday afternoon, with
KTPA/KPIE/KSRQ seeing best potential for a brief winds shift
to an onshore direction after 19Z.
&&
.Prev Discussion... /issued 237 PM EDT Wed Apr 12 2017/
SHORT TERM (Tonight - Thursday)...
A short wave trough over the northern Florida peninsula tonight
will dampen out as it drifts southeast along the Florida east coast
on Thursday and into the Bahamas Thursday night as upper level
ridging over the central Gulf re-builds slowly east in its wake.
At the surface high pressure over the Atlantic offshore the mid
Atlantic coast will maintain a northeast to easterly wind flow
over the region through the period.
For tonight any ongoing showers across central and southern
locations and the adjacent Gulf waters associated with a westward
moving inverted trough will end or shift west over the Gulf waters
after sunset with mainly dry conditions expected overnight.
Temperatures tonight will be near seasonal levels with lows in the
upper 50s north, and lower to mid 60s central and south.
On Thursday upper level ridging over the central Gulf will build
and expand slowly eastward during the day as the aforementioned short
wave trough dampens out along the Florida east coast and over the
Bahamas. Drier air (Pw`s less than 1 inch) advecting in from the
Atlantic during the day within the modest northeast to easterly wind
flow will support a warm and mainly dry day across the forecast
area with ample sunshine expected. The exception to this will be
across southwest Florida where slightly higher moisture combined
with the weak sea breeze may support a few showers late in the
afternoon where a low 20 percent pop mention will be advertised.
Temperatures on Thursday will continue to run a few degrees above
normal with highs climbing to around 80 to the lower 80s
along the coast, and mid 80s inland.
LONG TERM (Thursday Night - Wednesday)...
High pressure at the surface will be building into the region from
the NE as upper ridging over the Gulf shifts east over the state
through Saturday. The upper ridge will then become more zonal for
Sunday through Wednesday as the surface high settles south over the
west Atlantic ridging back across the state. Conditions will remain
mostly dry, with a few afternoon showers becoming possible for late
in the period Tuesday and Wednesday afternoons. Winds will be
generally E/NE through the period with some evening surges possible.
Temperatures will remain above normal through the period.
MARINE...
Surface high pressure offshore the mid Atlantic coast will get
reinforced by another ridge of high pressure moving offshore the
northeastern states late in the week and during the upcoming
weekend. The high will maintain an elevated northeast to easterly
wind flow (10 to 15 knots near shore and around 15 knots
offshore) over the Gulf waters through the period with
cautionary wind surges (in the 15 to 20 knot range) likely
during the evening and overnight time frames.
FIRE WEATHER...
Some pockets of humidity values below 35 percent will be possible
over interior sections of the forecast area during the next few
days, otherwise sufficient low level moisture should keep
humidity values above critical levels through the end of the
week and into the upcoming weekend with no Red Flag conditions
expected.
&&
.Preliminary Point Temps/PoPs...
TPA 65 82 63 84 / 10 0 0 0
FMY 65 83 63 85 / 30 20 10 0
GIF 62 82 61 84 / 10 0 0 0
SRQ 64 82 62 84 / 10 10 0 0
BKV 58 83 57 84 / 0 0 0 0
SPG 67 81 66 83 / 10 0 0 0
&&
.TBW WATCHES/WARNINGS/ADVISORIES...
FL...None.
Gulf waters...None.
&&
$$
UPDATE/AVIATION...Mroczka
PREVIOUS DISCUSSION...MCMICHAEL/HUBBARD