Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 03/27/17
Area Forecast Discussion
National Weather Service Bismarck ND
933 PM CDT Sun Mar 26 2017
.UPDATE...
Issued at 933 PM CDT Sun Mar 26 2017
A slight increase in POPs for the far north central was the only
adjustment made to the forecast. Chances for isolated showers
should dwindle down within an hour.
UPDATE Issued at 644 PM CDT Sun Mar 26 2017
Based on radar trends and current HiRes models, a slight chance
for rain was extended to 02Z. Sky cover was also adjusted/pulled
back to reflect current observations. Otherwise, current obs were
blended into the forecast and no other changes were made.
&&
.SHORT TERM...(This evening through Monday)
Issued at 237 PM CDT Sun Mar 26 2017
The main challenges for the short term will be precipitation
chances across the west this afternoon and overnight fog tonight
and into Monday morning.
This afternoon, a CU field had developed over much of western and
parts of central North Dakota. Very steep low level lapse rates
were located over the western third of the state, with some modest
MUCAPE (~250 J/kg) over the northwest. A few light radar echoes
have been pulsing on radar, so the thought is that isolated to
scattered convective showers will develop through the afternoon.
While a lightning strike or two is not out of the question,
confidence is too low to put thunder in the forecast at this
time. The latest runs of the HRRR and other CAMs all tend to agree
with this afternoon convective activity. As the sun goes down,
any lingering showers should begin to dissipate.
Overnight we are looking at favorable conditions for fog again
over the east, especially the James River Valley. Gradually
clearing skies, high soil/surface moisture, and very light winds
should aid in the development of areas of fog over the James River
Valley, with patchy fog possible further west and north.
.LONG TERM...(Monday night through Sunday)
Issued at 237 PM CDT Sun Mar 26 2017
The longer term features more of the same, a generally progressive
pattern with periodic chances of light precipitation. The best
chance for precipitation will likely be Tuesday night and into
Wednesday. The ECMWF had been the most bullish about precip
amounts, but even its latest 12z solution has settled down quite a
bit. Other waves bringing chances for light precipitation will
approach the area by the end of the work week and the weekend, but
there is still considerable uncertainty between the global
models with regards to timing. Above normal temperatures will
continue through the forecast period, with highs mainly in the 50s
and 60s.
&&
.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 644 PM CDT Sun Mar 26 2017
KJMS is the aviation concern for the 00Z TAF period. Fog is forecast
to develop in eastern areas of the state by 08Z. VLIFR visibilities
and ceilings are expected to impact KJMS through Monday morning.
Though fog may nose into KBIS, and perhaps KMOT, VFR conditions
are expected in western and central areas.
&&
.BIS WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...AC
SHORT TERM...ZH
LONG TERM...ZH
AVIATION...AC
Area Forecast Discussion
National Weather Service Caribou ME
1043 PM EDT Sun Mar 26 2017
.SYNOPSIS...
High pressure will move east of the area tonight as low pressure
approaches from the Great Lakes. Low pressure will cross the area
Monday into Tuesday.
&&
.NEAR TERM /THROUGH MONDAY/...
1035 PM Update...
Made some adjustments to the pops to bring percentages up across
the southern sections such as sw Piscataquis County and southern
Penobscot County. 00Z UA showed high pres ridge axis still well
w of the region w/dry air in place. Satl imagery showed
mid/high clouds across the north while clouds deck was lowering
this evening. Latest radar trends showing returns showing up
across the western section edging ene. Most of the activity was
aloft as llvls very dry. The latest run of the HRRR mesoscale
model doing well w/the precip placement. A frontal boundary was
in place across the region and radar returns were lining up
along this boundary per the 00z sfc analysis. Temps look like
they are going to be warmer than previously forecast and
adjustments were made to bring them overnight. Will monitor
the coast as some freezing precip is possible during the morning
hrs before going over to rain in the afternoon.
Previous Discussion...
Mainly clear skies this evening will give way to increasing
clouds tonight in advance of an approaching warm front. The air
mass across the region is very dry with dew points down around
zero across most of the region as of mid afternoon. The very low
dew points and light winds will allow for some radiational
cooling this evening before clouds thicken up after midnight.
The coldest reading are likely to be across far northeast
Aroostook County and the St John Valley where lows are expected
to fall into the single digits above zero before clouds thicken
later tonight. With the very dry low level air in place, it will
also take a while for precipitation to reach the ground, so not
expecting precipitation to develop until well after midnight
across the west and probably not until around or a bit after day
break across Northeast Aroostook and the St John Valley.
Overrunning precipitation will continue overspread the region
early Monday. Across the north the precipitation should remain
mainly snow much of the day. Across central and interior
downeast areas, expect snow to mix with sleet and freezing rain
by afternoon. Across the downeast coast, expect a brief period
of mixed precipitation in the morning to transition to plain
rain by afternoon. A weak area of low pressure developing along
the front to our south will cross the gulf of Maine during
Monday afternoon, keeping the low level cold air in place. Thus,
have leaned with cooler mos numbers for highs on Monday. Winter
Weather advisories have been issued for all of Northern Maine
for Monday. With the low level cold air expected to hang tough
into the afternoon, have also included the Penobscot region and
greater Bangor region, as well as all of interior downeast in
the Winter Weather Advisory. There could be a mix even along the
downeast coast into Monday morning, but thinking there may be
enough warming for a transition to all rain by afternoon, thus
have not included in the advisory at time. Highs on Monday are
expected to range from the upper 20s across the north to the low
to mid 30s along the coast.
&&
.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY/...
A large but poorly organized storm system will be moving into the
area Monday evening with one low center along the coast and another
to our west. Temperatures Monday evening will be warm enough for
some light rain and drizzle Downeast. A mix of snow, sleet and
freezing rain is likely across the north with all snow possible
across the far north near the St. John Valley. Precipitation will
generally be light, and will diminish late at night as one low
center near the coast moves east and another remains back across
Quebec. As the Quebec low crosses the area on Tuesday, some rain
showers will be scattered over the region. Any showers may be mixed
with some sleet or snow pellets across the far north with little or
no accumulation expected. Some light rain, and snow showers across
the north, may continue into Tuesday night as a weak occlusion
crosses the area. Drier air should then begin moving into the region
on Wednesday. However, low pressure consolidating south of Nova
Scotia will have an inverted trough extending back across New
Brunswick on Wednesday. If this inverted trough sets up further
west, some scattered rain and snow showers could be possible. For
now, will only have sight chance of snow or rain showers on
Wednesday.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
Low pressure will move away to the east Wednesday night into
Thursday as gusty northwesterly winds follow. The air will only be
moderately cooler with highs Thursday expected to be in the 30s
north and 40s Downeast. High pressure will then build over the area
Friday into Saturday bringing plenty of sunshine. Low pressure will
be tracking off the Mid-Atlantic coast on Saturday, but should track
far enough south to miss our area. Generally dry and mild weather is
then expected late next weekend as upper level ridging along the
east coast combined with low pressure over central Canada brings a
southwesterly flow across the area.
&&
.AVIATION /02Z MONDAY THROUGH FRIDAY/...
NEAR TERM: VFR through most of tonight. Conditions will deteriorate
to MVFR 09z to 12z, then to IFR in a wintry mix on Monday at
all terminals.
SHORT TERM: IFR conditions in low clouds and snow and rain are
expected Monday night through Tuesday. IFR conditions Tuesday
evening may improve to MVFR late at night, then VFR on
Wednesday. VFR conditions are likely on Thursday as high
pressure approaches. VFR conditions in high pressure are
expected on Friday.
&&
.MARINE...
NEAR TERM: Winds/seas will remain below small craft advisory
levels tonight. Winds/seas will begin to increase to small craft
advisory levels by late Monday afternoon. Visibilities will
decrease to 1 to 3 nm in precipitation late tonight through
Monday.
SHORT TERM: A SCA will be needed Monday evening for
southeasterly winds gusting up to 30 kt ahead of approaching low
pressure. Winds will diminish late Monday night into Tuesday.
Some fog may limit visibilities late Monday night into Tuesday
as surface low pressure crosses the waters.
&&
.CAR WATCHES/WARNINGS/ADVISORIES...
ME...Winter Weather Advisory from 5 AM to 10 PM EDT Monday for
MEZ001>006-010-011-015>017-031-032.
MARINE...Small Craft Advisory from 10 PM Monday to 3 AM EDT Tuesday for
ANZ050>052.
&&
$$
Near Term...Hewitt
Area Forecast Discussion
National Weather Service Duluth MN
655 PM CDT Sun Mar 26 2017
.SHORT TERM...(This evening through Monday)
Issued at 251 PM CDT Sun Mar 26 2017
A mid-level shortwave, with an associated sfc low, will advance
across northern Illinois into Michigan tonight. A ribbon of positive
vorticity advection that has supported rain/freezing rain across
portions of the Northland this morning will weaken while the
shortwave translates to the northeast. A secondary shortwave trough
that has developed out of the Four-Corners region this morning will
help push the previous shortwave to the east, while ejecting a
northern stream ribbon of PVA into the Northland later this evening
and overnight. Modest to weak isentropic lift looks to be associated
with this northern stream, so not sold on it supporting any
precipitation. Additional inhibition is provided by a push of drier
850-600 mb layer air, as evident in the latest NAM and RAP model
soundings, which removes the deeper moisture that has been in place
this morning. So, have decided not to include POPs with this
shortwave at this time. Areas of fog are also expected to develop
tonight as a low-level inversion traps boundary layer moisture,
along with light winds in place. Model guidance is hinting at
some of the thickest fog possible over the Iron Range area north
towards the International Border, and along the Gogebic Range
areas of Iron and Ashland counties. Visibilities could reduce to
as low as 2 SM in some spots, but most of the Northland should see
reductions between 3 to 5 SM.
Chances of precipitation should ramp down somewhat later this
evening, but maintaining over northwest Wisconsin overnight as
weak PVA lingers over this area. The northern PVA ribbon looks to
reinforce this lingering PVA. Moreover, deeper moisture should linger
over this area through Monday morning. So, kept chances of rain
showers for the eastern portions of our NW WI forecast area. Some
freezing rain may also develop as temperatures cool down overnight
and Monday morning. However, QPF should not be quite as high as
it was this morning, so not expecting much ice accumulation, if
any at all. Any lingering precipitation should diminish by Monday
afternoon as high pressure builds into the region.
.LONG TERM...(Monday night through Sunday)
Issued at 251 PM CDT Sun Mar 26 2017
Split flow pattern will continue for most of the upcoming week, with
the primary storm storm track remaining to our south from the
central Plains States into the middle Great Lakes, and another
series of fast-moving waves traversing Canada to our north in faster
more zonal flow aloft.
Overall, this will mean generally tranquil weather with a slow
warming trend, although there will be a few small chances for
precipitation with several weak disturbances traversing the region.
Temperatures, especially at night and during the early mornings, may
be sufficiently cold to support some wintry mixed precip, but
overall this should not amount to many significant impacts.
&&
.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 655 PM CDT Sun Mar 26 2017
Low pressure over southern Lake Michigan this evening will
continue northeast tonight and an upper level disturbance will
also move through the region. Light rain from the North Shore into
the Pine City area this evening will continue east through the
evening. The cloud forecast will be quite variable across the
Northland tonight with mostly VFR conditions over far northern
Minnesota this evening and MVFR/IFR ceilings around Lake Superior
and over northwest Wisconsin. VFR conditions will develop further
south through the evening but as the night progresses more MVFR
and IFR ceilings will develop. Fog will also be possible, most
widespread and dense around Lake Superior. As weak high pressure
moves over the region Monday, conditions will gradually improve
for most areas.
&&
.PRELIMINARY POINT TEMPS/POPS...
DLH 32 43 28 47 / 30 10 0 0
INL 30 46 27 48 / 0 0 0 10
BRD 33 54 30 56 / 10 10 0 0
HYR 32 45 26 52 / 30 20 0 0
ASX 31 42 26 45 / 30 10 0 0
&&
.DLH WATCHES/WARNINGS/ADVISORIES...
WI...None.
MN...None.
LS...None.
&&
$$
SHORT TERM...JTS
LONG TERM...Miller
AVIATION...Melde
Area Forecast Discussion...UPDATED
National Weather Service Austin/San Antonio TX
658 PM CDT Sun Mar 26 2017
.AVIATION...
/00Z TAFS/
VFR conditions will prevail across area terminals through late
evening. Clouds will develop along the Coastal Plains and then move
toward the north this evening and over the I-35 sites by midnight
tonight. MVFR cigs are anticipated by 05Z with IFR cigs starting
around 08Z/09Z across Austin and San Antonio airports. There are
indications from several HiRes models and guidance for cigs to go
down as low as LIFR for Austin around the 12Z time frame and have
included this as such for KAUS. MVFR are forecast to linger around
through 16Z for the I-35 terminals with VFR returning by 17Z and
staying that way through Monday evening. Southeasterly winds will
prevail through the forecast period with 5 to 15 knots overnight into
Monday morning and decreasing 5 to 10 knots Monday afternoon.
KDRT should remain VFR through late tonight with MVFR expected by
11Z. There is a chance for cigs to lower to LIFR for an hour or two
just like this morning and have added it to this forecast cycle.
Good mixing takes place out west along the Rio Grande by late morning with
VFR returning by 16Z Monday.
&&
.PREV DISCUSSION... /ISSUED 319 PM CDT Sun Mar 26 2017/
SHORT TERM (Tonight through Monday Night)...
Severe weather risk this afternoon remains non-zero but is still
extremely marginal. Currently, satellite imagery is showing some
bubbling cu from Mason County to Fayette County. Latest LAPS
soundings show a weak cap struggling to hold on this afternoon and
RAP forecast soundings keep it holding on through out the afternoon.
Also of note is the presence of about 20-50 J/KG of CIN working
against heated parcels at the surface. If a surface boundary of some
kind were present, concerns would be much higher for the chance for
CI this afternoon, but with surface dewpoints in the 50s west of I-35
and lack of lifting mechanism present east, think its very unlikely
parcels will be able to tap into the ripe conditions aloft. SPC
mesoanalysis shows LFC heights over 4000m thus surface parcels will
need to overcome inhibition, weak surface moisture, and without any
help to lift it to get to that height. Thus, confidence is extremely
low for the chance for storms.
Should one occur though, effective bulk shear, lots of instability,
and strong mid level lapse rates all mean the possibility for strong
to severe storms with large hail and damaging winds.
LONG TERM (Tuesday through Sunday)...
The focus for the short term will be the prospect of severe weather
with our next upper low Tuesday and Wednesday. SPC has already
outlined marginal to slight risk for large hail, damaging winds, and
tornadoes Tuesday and a day 4 area outlined for the Austin area and
northeast Wednesday. Our best timing for severe potential will likely
be late Tuesday night, and maybe as late as early Wednesday morning
(after midnight) as we inherit a mature system that develops near
Abilene. Latest ECMWF shows convection initiating along the dry line
near the Childress area and unzipping southward to Del Rio by
midnight Tuesday night. Overnight, these cells become more
dynamically driven and likely coalesce into a linear system that
pushes across the CWA from the west and impacts the I-35 corridor by
12Z Wednesday morning. While PWAT values over 1.5" have been
advertised thus far, both GFS and ECMWF quickly exit the system after
18Z Wednesday and should limit flash flooding potential. Should this
system indeed become a linear system as advertised, the principle
threat should be damaging straight line winds and hail.
&&
.PRELIMINARY POINT TEMPS/POPS...
Austin Camp Mabry 67 88 67 84 67 / 10 10 - 20 40
Austin Bergstrom Intl Airport 66 88 67 84 67 / 10 10 - 20 40
New Braunfels Muni Airport 66 88 67 84 67 / - 10 - 20 40
Burnet Muni Airport 63 85 63 80 64 / 10 - - 30 70
Del Rio Intl Airport 60 92 66 87 62 / - 0 - 30 50
Georgetown Muni Airport 66 87 65 81 65 / 10 - - 30 50
Hondo Muni Airport 65 92 66 85 66 / - - - 30 40
San Marcos Muni Airport 66 89 66 84 68 / 10 10 - 20 40
La Grange - Fayette Regional 68 87 67 84 69 / 10 10 - 10 30
San Antonio Intl Airport 67 89 68 84 68 / - - - 30 40
Stinson Muni Airport 67 89 67 84 68 / - - - 20 40
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
Mesoscale/Aviation...17
Synoptic/Grids...Allen
Public Service/Data Collection...Williams
Area Forecast Discussion
National Weather Service Green Bay WI
657 PM CDT Sun Mar 26 2017
Updated aviation portion for 00Z TAF issuance
.SHORT TERM...Tonight and Monday
Issued at 318 PM CDT Sun Mar 26 2017
The latest RAP analysis and satellite/radar imagery show low
pressure spinning along the Illinois/Wisconsin border early this
afternoon. Rain showers continue to wrap around the low across much
of eastern WI. Where its not raining, periods of drizzle are
occurring into north-central WI. Visibilities improved with the
arrival of more persistent showers, but dense fog does exist in
close proximity to the surface low. Looking upstream, broken clouds
prevail all the way into eastern North Dakota. As the low lifts
northeast, precip trends are the main forecast concern.
Tonight...Low pressure will be moving northeast from southern Lake
Michigan to Lake Huron tonight. The most persistent showers will
likely occur over northeast Wisconsin during the evening where the
warm conveyor belt wraps around the upper circulation. Progged
soundings indicate that saturation remains pretty deep up to 700mb
for most areas through the night though, so even if showers have the
highest coverage over the northeast, cannot rule out isolated
showers and/or areas of drizzle elsewhere. Winds will lighten a bit
through the night, which will support lowering visibilities with the
ample moisture in place. However, dense fog appears only possible
near the center of the surface low, that will pass southeast of the
area. So think we may escape without a dense fog advisory, though
it may be close along the lakeshore. Without any semblance of
temperature advection in addition to the widespread low clouds,
expect little fall of temperatures tonight. The warmer temperatures
should confine any freezing precip right near the U.P. border, if
there is any.
Monday...The upper low will exit the region, but will see a weak
shortwave move across northern WI and the Upper Peninsula. This
shortwave will bring a chance of showers, but coverage should be
limited due to weak forcing. Otherwise, cloudy conditions should
prevail for much of the day with little dry air to push out the
moist airmass. North-central WI has chance for partial clearing
late in the day behind the shortwave. Highs will return into the
low to mid 40s.
.LONG TERM...Monday Night Through Sunday
Issued at 318 PM CDT Sun Mar 26 2017
After wet period across the area, the long term will start off on
a drier note, but another system at the end of the week will
bring wet/wintry weather back as another low pressure system
tracks across the Great Lakes. No drastic temperatures swings are
expected, with near to above normal readings.
For Monday night, lingering light showers or sprinkles are
possible as low pressure passes across the Ohio Valley, a mid-
level trough passes across Lake Superior, and a departing upper
jet Monday evening is quickly followed by an approaching upper jet
overnight into Tuesday morning. Think slight chance pops will
cover for the evening hours. Drier air works into the area by
Tuesday, so dry conditions are expected. Tuesday looks to be the
best chance to see some sunshine this week, but forecast
soundings are showing some lingering moisture both at low and mid-
upper levels which could lead to some clouds. Tuesday also looks
to be the warmest day of the week, with highs in the upper 40s to
lower 50s for most locations.
Surface high centered over northern Ontario early Wednesday will
extend/shift south and east into the Great Lakes on Wednesday.
The surface high along with mid-level ridging will provide for a
dry day. An impressive moisture push from the west and southwest
ahead of the next low pressure will bring mostly cloudy to the
area by afternoon as a thick mid layer cloud deck is expected,
with some lower clouds possible too.
Dry weather looks to hold on until early Thursday morning, then
all eyes will be on an approaching low pressure system. The mid-
upper closed low will eject out of southwest U.S. during the day
on Wednesday, then be on our doorstep Thursday morning (GFS a
little slower). The GFS remains farthest south with the system
and only brushes central and east central WI with some precip.
ECMWF/Canadian remain farther north. Other smaller scale
differences exist, especially with where the deformation band will
set up on Friday.
Temp profiles will be critical as the precip arrives on Thursday
(and through the whole day if current trends continue), with the
heaviest precip in the Thursday afternoon/evening timeframe and a
secondary max possible sometime on Friday as the low pressure
passes just to our south/east. The way it looks now, low level
temps and wet-bulb temps look to be just cool enough for
evaporative cooling effects to allow the precip to start off as a
wintry mix Thursday morning, assuming the precip arrives on time.
As the heavy precip moves in later in the day, a change over to
rain is expected for the entire area. That said, the heavier
precip will keep the temp profile very close to the rain/snow
line, so there is a chance the precip could stay a wintry mix
longer, especially over the north. A change over back to a mix is
possible Thursday night as temps cool. This far out a blend of the
models seems reasonable (least confidence in the GFS), but
adjustments will likely be needed as we get closer to the event
and confidence on how low level temps will behave becomes more
clear.
After the system pulls out on Friday, dry weather returns to the
area on Saturday as brief ridging builds across the Great Lakes.
Chances for precip arrives again on Sunday as a fast moving
clipper type system crosses southern Canada, but models differ on
how far south this system will track.
&&
.AVIATION...for 00Z TAF Issuance
Issued at 656 PM CDT Sun Mar 26 2017
IFR conditions will continue through midday Monday or
maybe a bit longer as low pressure moves slowly away from
Wisconsin. Light rain will accompany the low clouds at times.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
SHORT TERM.....MPC
LONG TERM......Bersch
AVIATION.......RDM
Area Forecast Discussion
National Weather Service Jackson MS
930 PM CDT Sun Mar 26 2017
.UPDATE...
Updated for evening discussion.
&&
.DISCUSSION...
Latest surface analysis shows a low over SW Oklahoma with decent
convective coverage in the warm sector and along the dryline. A
closed mid- and upper-level low was centered over W Kansas with an
associated trough extending through the Southern Plains. Surface
ridging along the East Coast has allowed southerly flow to
continue across the CWA ahead of the advancing system out of the
Southern Plains which has helped to keep warm temperatures and
upper 50s to low 60s dewpoints across the region. For the
remainder of the overnight, latest hi-res CAM guidance is in
agreement on weakening and eventually dissipating the organized
convection emanating from the Southern Plains as it moves into an
area of capping and less instability/forcing. This will limit any
convection concerns across the area tonight and into early
tomorrow morning, however an isolated shower or rumble of thunder
cannot be entirely ruled out across the Delta. Some of the hi-res
guidance has been more aggressive in shower/isolated storm
development after sunrise tomorrow morning as a remnant outflow
boundary interacts with increasing moisture and instability,
however given the capping issues confidence is not very high on
more than isolated coverage at the moment. Patchy fog will also be
possible overnight and into tomorrow morning mainly in the
southeast where the best moisture return and calmer winds will be.
Coverage and visiblities are not expected to be great enough to
warrant mention in the HWO at the moment, but will let the next
shift monitor any trends. Otherwise, temperatures will stay on the
mild side area wide with southerly flow and increasing cloud
cover through the period. See the prior discussion below for
information regarding Monday`s severe weather potential. /TW/
Prior discussion below:
Tonight and Monday: WV imagery this afternoon showing impressive
cold core system moving into the central Plains with warm
advection ascent taking shape over TX/OK. Meanwhile in our neck of
the woods, much of the cloud cover from this morning has mixed
away as dewpoints have fallen into the 50s. Better dewpoints are
poised over southern sections to advance northward over the area
again tonight. As this occurs, fog and low clouds will spread in
from the south mainly after midnight.
The HRRR is indicating that currently developing MCS over OK will
grow eastward overnight into AR, but diminish toward sunrise over
eastern AR as it moves into a more capped environment. Some concern
exists for its outflow to help force new convection over northern MS
in the morning, but models soundings continue to show impressive
capping that does not look to weaken until the afternoon. A less
impressive cap will exist over the northeast and it is in this area
that convection may initiate by afternoon. While a damaging wind
threat will exist with the storms, environmental parameters suggest
that large hail will be the primary threat. Cells look to be
scattered in nature during the afternoon and early evening until the
surface cold front moves in later in the evening. South of I20, the
cap strength looks to remain strong enough to only allow for
isolated convection, but severe potential will exist with these
storms as well. The convection will diminish toward late evening
with the loss of daytime heating./26/
Monday night through the week...As the system that should bring
us some potential severe weather departs to the northeast Monday
night, it will leave a cold front draped across the north central
portions of the ArkLaMiss region. Some light showers may linger
along or near this front Monday night but the remainder of the
region will begin to dry out. Upper ridging will move overhead for
Tuesday, but as daytime heating occurs, additional showers/storms
may develop around this stalled front.
The upper ridge will push east through Tuesday night and into
Wednesday but will still have some hold on our area Wednesday. This
will keep conditions warm but mostly dry. The aforementioned stalled
front will move north as a warm front during the day on Wednesday,
which could ignite some warm advection showers across my far
northern counties(or develop completely north of my CWA). Our next
weather system will continue to develop out to our west. By
Wednesday evening, a 998mb surface low will be located across the
Rolling Plains of Texas as the upper trough/closed low will be
located slightly further north across the Texas Panhandle. A dryline
feature will be across the eastern Pineywoods of Texas with storms
along/ahead of this feature in western Louisiana. Across our area, a
rather moist and unstable airmass will be in place with dewpoints in
the lower to mid 60s and temperatures having reached the lower to
mid 80s during the afternoon. During the evening hours, as the
surface low tracks to the north and east and the upper trough starts
to swing east, this line of storms should enter my western
counties/parishes and continue to track east overnight. Our
atmosphere will be rather unstable with steep lapse rates (Vertical
Totals of 28-31C and 7-8C/km mid level lapse rates) and greater deep
layer shear than we saw in previous events (40-45kts 0-6km shear)
and helicities are depicted as being 200-400 m2/s2. All of this
suggests that all hazards will be possible. Conditions look just as
good on Thursday, especially if the overnight line doesn`t work over
the atmosphere. Looks like there could be several rounds of weather
with this event from Wednesday night through Thursday. In addition,
with PW values around 1.5-1.7 inches, there could be some locally
heavy rainfall which perhaps could lead to some isolated flooding
instances given recent rainy conditions. Will continue with the
slight risk as highlighted by the previous shift, but expect that
this will be increased as the event gets closer and more details are
ironed out.
As the system pulls off to the northeast by Thursday evening/night,
rain will move out of the area and upper ridging will again move in
for the early part of the weekend. Springlike temperatures will
continue through the period with highs in the 70s and 80s and lows
in the 50s and 60s. /28/
&&
.AVIATION...
00Z TAF discussion: Very few clouds were noted satl imagery at
2330Z and VFR conds were observed at all TAF sites. VFR conds wl
prevail this evening but MVFR vsby wl be psbl HBG-MEI by 06Z and
lower to IFR by 11Z. MVFR cigs are expected to develop at most
sites by 09Z lowering to IFR by 11Z before improving after 15Z
Mon. TSRA activity wl come in vcty of GLH by 15z and elsewhere Mon
aftn. /22/
&&
.PRELIMINARY POINT TEMPS/POPS...
Jackson 64 83 63 81 / 2 39 37 29
Meridian 62 82 63 81 / 2 42 35 30
Vicksburg 64 83 64 81 / 1 37 35 28
Hattiesburg 64 82 64 82 / 9 34 21 27
Natchez 65 82 66 82 / 2 37 26 27
Greenville 63 79 59 76 / 6 42 36 19
Greenwood 63 81 61 77 / 5 55 58 25
&&
.JAN WATCHES/WARNINGS/ADVISORIES...
MS...None.
LA...None.
AR...None.
&&
$$
TW/22/26/28
AREA FORECAST DISCUSSION...UPDATED
National Weather Service Jackson KY
1054 PM EDT Sun Mar 26 2017
.UPDATE...
Issued at 1054 PM EDT SUN MAR 26 2017
Thunder has ended across the area, and will remove this for the
rest of the night. Some isolated to scattered showers will
continue to linger across the area through the next few hours,
before diminishing. There are some thinner spots in the cloud
cover upstream, and with a slackening pressure gradient expected
through the rest of the night and recent rainfall, will include
some patchy dense fog across the area. Low temperatures will
average in the mid 50s, and have mainly freshened up the hourly
temperature drop off. Updates have been sent.
UPDATE Issued at 813 PM EDT SUN MAR 26 2017
A few clusters of showers and isolated thunder are shifting
northeast across portions of eastern Kentucky early this evening.
One of these will pivot through the I-64 in the next hour, while
another one will exit into West Virginia. The latest HRRR has been
showing additional activity firing up in the next 2 to 3 hours;
however, with the better forcing moving off to the northeast and
the loss of heating, am leaning more towards a gradual weakening
trend, which has been the case upstream. Have freshened up the
POP trends over the next few hours, with thunder chances ending
in the next 1 to 2 hours, as the aforementioned clusters of
convection exit. Have also included some patchy fog, with pockets
of clearing and some locally heavy rainfall having occurred.
&&
.SHORT TERM...(This evening through Monday night)
Issued at 300 PM EDT SUN MAR 26 2017
The short term period will be active, with numerous showers and
isolated thunderstorms moving across the area through around 2Z
this evening. A few of the storms this afternoon could produce
hail and strong wind gusts. The thunder chances should only last
through 23 or 0Z, as any remaining instability and best forcing
should be gone after that. General rain showers are expected
overnight, and these will taper off steadily through 6Z, and
should be gone by around 9Z. After a very brief reprieve, we
should see more showers moving into the area from the south and
southwest between 12 and 13Z on Monday. Isolated to scattered
thunderstorms will be possible again after 17Z on Monday. There
will be a good chance of thunder Monday night as well, as a strong
area of low pressure aloft and a fast moving but weak cold front
both move across the region. Mostly cloudy to cloudy skies will
also be on tap, as ample moisture will continue streaming into the
area from the south. Temperatures through out the period will
continue to run well above normal, with nightly lows in the 50s,
and highs on Monday in the low to mid 70s expected.
.LONG TERM...(Tuesday through Sunday)
Issued at 440 PM EDT SUN MAR 26 2017
The period is expected to begin with a mid and upper level trough
moving through the OH Valley region and into the Appalachians that
shifts east during the day on Tuesday and takes deeper moisture
with it. The associated surface low is expected to move into the
Mid Atlantic states by Tuesday evening and take the cold front
across the area on Tuesday morning. Mid and upper level ridging
should build in behind it, with surface high pressure nosing into
the OH Valley at midweek. This should bring a break in the
unsettled weather with mild and drier weather from late Tuesday
evening through Wednesday night.
The pattern will remain rather active with the next in a series
of upper lows or shortwaves moving from the Southern Rockies
across the Plains and into the mid MS and OH Valleys from Wed
through Thursday evening. There is also some timing and strength
differences with the upper and surface low beyond Thursday. The
general consensus however, is for the upper and surface system to
track to the west and north of the area from Thursday through
Friday night and bring additional rounds of showers and a few
thunderstorms to the area. This system should continue to depart
on Saturday with surface and upper level ridging building in for a
dry end to the weekend.
Chances for showers will be highest to start the period, followed
by a lull at midweek. The next system will bring another period of
unsettled weather with pops in the good chance to likely range
form Thursday into Friday evening. At this point, next weekend is
expected to end on a dry note.
High temperatures should average above normal for most of the
period, although highs on Wednesday and Saturday should be near
normal for late March/Early April. Lows will also be mild and at
this point are not expected to fall below 40 at any point, even in
the normally colder valley locations.
&&
.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
ISSUED AT 813 PM EDT SUN MAR 26 2017
Showers and isolated thunderstorms will gradually come to an end
across the area through 06z. Outside of showers, mainly VFR
conditions will be seen. Some lower stratocu looks to develop
between 06 and 12z, mainly along and north of a line from JKL to
PBX. Patchy fog may also reduce visibilities down to MVFR,
although this will depend on clearing and how light winds become
overnight. Another round of scattered showers and a few
thunderstorms will threaten during the late morning and afternoon
hours on Monday. Winds will remain out of the south and southwest
through the period, averaging between 5 and 10 kts during the day
and around 5 kts at night.
&&
.JKL WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
$$
UPDATE...GEOGERIAN
SHORT TERM...AR
LONG TERM...JP
AVIATION...GEOGERIAN
Area Forecast Discussion
National Weather Service Marquette MI
831 PM EDT Sun Mar 26 2017
.SHORT TERM...(This evening through Monday)
Issued at 320 PM EDT SUN MAR 26 2017
Water vapor imagery and RAP analysis show a mid level low centered
over northern IL. Deep moisture associated with this feature surged
back to the n across Upper MI last night into today, bringing
periods of -ra/-fzra. Upslope e to se flow also resulted in some
patchy dense fog this morning into early afternoon over portions of
the Keweenaw Peninsula...Dickinson and southeast Marquette counties.
Models show the mid-level low and assoc trough lifting ne through
Lower Mi this evening and then into Ontario late tonight/Mon
morning. With movement of the mid-level trough the 850mb trough and
weak isentropic ascent also shifts e tonight, so expect pcpn over
mainly the central and eastern fcst area to diminish. However with
abundant moisture, developing nnw upslope flow and approaching weak
shortwave, some -ra/-fzra will remain possible over the w tonight.
Sfc temps should slip back to around freezing over the w and n
central, so there may still be a little bit of icing at some
locations late tonight. However, accumulations should be minor so no
statement will be issued at this time. Expect some fog as well.
Weak northerly flow between sfc low over eastern Ontario and sfc
high building into south central Canada will result in murky weather
conditions with some fog and possible light drizzle or freezing
drizzle Mon morning mainly over upslope locations of west and north
central U.P. Forcing from incoming northern stream shortwave could
enhance upslope pcpn turning dz/fzdz to -ra/-fzra for a time late
morning into mid aftn. NAM soundings suggest could even be brief
period of sleet or snow mixing in over west and northwest with
evaporative cooling aloft. Limited moisture depth as noted on NAM
soundings will not warrant anything more than slight chc to low chc
pops. Expect highs in the mid 30s to lower 40s, warmest e and se
under cloudy skies.
.LONG TERM...(Monday night through Sunday)
Issued at 401 PM EDT SUN MAR 26 2017
Rather benign weather is expected through much of the period as a
slow-moving mid to upper ridge is gradually replaced by a mid-level
low drifting NE from the southern plains.
Lingering low-level moisture may allow for a light wintry mix for
the higher terrain along Lake Superior, and patchy fog across most
of the CWA, Monday night. A fairly shallow and sharp inversion may
keep low clouds across the area well into Tuesday afternoon, but
gradual mixing through the day should erode most of the clouds by
the evening. Dry conditions are then expected through Wednesday with
the ridge settling over Lake Superior and northern Ontario. N to NE
winds will likely keep temps in the mid 30s both Tuesday and
Wednesday along Lake Superior.
The NW extent of a somewhat closed mid-level low will then brush
mainly the SE half of the CWA Thursday night into Friday night.
Again, precip type will be in question with cloud-layer temps aloft
only slightly below freezing. However, marginal upper-level cloud
seeding and the absence of a pronounced warm layer should limit the
amount of freezing rain.
Inconsistencies in the model guidance develop by next weekend, with
mixed signals regarding a weak mid-level trough traversing the area
Saturday night. Will maintain chance PoPs at this point.
&&
.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 822 PM EDT SUN MAR 26 2017
Abundant low-level moisture over the area should lead to prevailing
LIFR conditions at KIWD/KCMX/KSAW through tonight. Some
-FZRA is still possible but temperstures are expected to remain at
or just above freezing. Fog late tonight may be low enough to drop
vsby near landing minimums at KSAW. Drier air moving in on Monday
will result in improving conditions during the morning into the MVFR
range at KIWD and KCMX. IFR cigs should still linger at KSAW into
the afternoon.
&&
.MARINE...(For the 4 PM Lake Superior forecast issuance)
Issued at 320 PM EDT SUN MAR 26 2017
With no signIficant weather systems affecting the Upper Great Lakes
this week, no gales are expected on Lake Superior. In fact, winds
will mostly be under 20kt.
&&
.MQT WATCHES/WARNINGS/ADVISORIES...
Upper Michigan...
None.
Lake Superior...
None.
Lake Michigan...
None.
&&
$$
SHORT TERM...Voss
LONG TERM...Kluber
AVIATION...JLB
MARINE...Voss
Area Forecast Discussion
National Weather Service Omaha/Valley NE
628 PM CDT Sun Mar 26 2017
.SHORT TERM...(Tonight through Wednesday)
Issued at 305 PM CDT Sun Mar 26 2017
Main forecast concerns are in regards to precipitation timing and
location tonight into Monday morning, then precipitation chances
returning Tuesday and continuing into the long term.
Upper air charts from 12Z this morning had the following main
features of interest. A jetstreak of over 100 knots at 300 mb was
moving toward the northern CA coast. At 500 mb, one closed low was
near the IA/MO/IL border and another was over southeast CO. The
second low had 12 hour height falls of up to 100 meters at KABQ.
As of mid afternoon, that feature was moving into southwest KS.
Like yesterday, there was some convection right near the center of
the low with the cold pocket. Convection also noted over OK in
part of the baroclinic leaf that had formed ahead of the low. At
the surface - low pressure was over the OK panhandle, while a
warm front extended east from the low toward the MO/OK/KS border
area. Dewpoints in the 50s F were streaming northward south of the
front. Closer to home, a weak surface ridge was over eastern NE
and western IA with temperatures in the 40s and dewpoints in the
upper 30s/lower 40s.
Tonight...we should see an increase in showers into the southern
parts of the forecast area. Trend from previous forecast was good,
just modified timing, northward extent of POPs and also increased
those POPs a little near the KS and MO borders. A fair amount of
weight was given to the RAP, experimental HRRR and NAM output.
General consensus is that amounts should be mostly less than 0.25
inches, although the 12Z GFS suggested there could be some
amounts higher than that. Convective potential seems best south of
our area, so did not mention thunder at this time.
Showers should linger in the southeast part of the forecast area
Monday morning, then we look for a dry period from Monday
afternoon into Tuesday morning. By 12Z Tuesday, a new mid level
closed system should have moved into the four corners region, with
modest diffluent flow over the central Plains. That low is
expected to track into western Oklahoma by Wednesday evening.
Increasing moisture and forcing should result in development of
light rain or showers over our western counties by late Tuesday
afternoon. The 12Z GFS was just a bit faster than the 00Z ECMWF,
so there are some timing differences that will need to be resolved
the next few shifts. But by Tuesday night, most model guidance
brings rain into our area. Right now, think that precipitation
amounts from Tuesday Night into Wednesday should be from 0.25 to
0.75 inches. The ECMWF does show a bit more than that though.
.LONG TERM...(Wednesday night through Sunday)
Issued at 305 PM CDT Sun Mar 26 2017
Rain should linger Wednesday night and then decrease from west to
east on Thursday as the mid level system moves east and the
deformation zone weakens. Heaviest rain, potentially over an inch,
should be across southeast NE into southwest IA. Most if not all
of the precipitation should be in liquid form, but did allow for a
very short window of a rain/snow mix west of highway 81 in
northeast NE late Wednesday night into mid morning Thursday.
The period from Thursday night into Friday evening looks mainly
dry, but another system could bring rain for at least parts of
the area next weekend. Model agreement is not great by that time,
so confidence does drop to normal or below normal by Day 7. The
ECMWF is a bit wetter than the GFS, especially Saturday into
Saturday Night.
&&
.AVIATION...(For the 00Z TAFS through 00Z Monday evening)
Issued at 612 PM CDT Sun Mar 26 2017
MVFR/patchy IFR cigs will prevail overnight tonight with a large
area of low level moisture in place. May also see some patchy MVFR
vsbys with fog. Mid-level cyclone over western Kansas will track
across eastern Kansas through tonight. The better low level
forcing will remain to the south of the TAF sites although there
is some mid and upper level forcing which will try to spread some
of the light rain toward southeast Nebraska. Forecast soundings
are hinting that as the storm system exits the area in the
afternoon that we will see the clouds scatter out. Trended these
improving conditions into the TAFS 18-21Z.
&&
.OAX WATCHES/WARNINGS/ADVISORIES...
NE...None.
IA...None.
&&
$$
SHORT TERM...Miller
LONG TERM...Miller
AVIATION...Zapotocny
Area Forecast Discussion
National Weather Service Spokane WA
435 PM PDT Sun Mar 26 2017
.SYNOPSIS...
One storm system will bring light rain and mountain snow tonight
into Monday morning. Showery weather is expected through Tuesday
then a widespread moderate precipitation event will arrive on
Wednesday and Thursday. Friday will bring a dry break period
before more unsettled weather for next weekend.
&&
.DISCUSSION...
Tonight through Monday night: A moist frontal system will pass through
the region tonight and Monday delivering periods of light rain
and mountain snow. There is a decent moisture fetch tied to the
system however the dynamics will be weak and splitting with the
strongest lift tracking south into Oregon and most locations will
receive less than a quarter of an inch from this system. The
exception will be along the Cascade Crest, Blue Mtns, and into the
Camas Prairie where upward of half an inch will be possible.
As of 2PM...we were monitoring the first band of rain associated with
the warm front expanding into Ern WA and N ID. Rainfall amounts
have been light and on the order of a few hundredths or less.
Several runs of the HRRR indicate the potential for a brief break
in the rain behind the warm front however a cold front currently
on the WA Coast will limp through the region allowing a line of
precipitation to redevelop overnight. Satellite imagery also
indicates a strengthening jet digging down the backside of the
trof. Not only will this serve to split the energy south but also
slow the entire system down...thus the slow cold front passage.
The front will also loosen its thermal packing or frontal
structure, all factors contributing to a rather light
precipitation event.
The front will begin to clear east of the region Monday morning then
cooling aloft will aid to destabilization and likelihood for
convective showers. Just about all locations will have a chance
for an afternoon shower but westerly flow will keep the lee of the
Cascades at a slight risk and rising terrain of Ern WA and N ID,
greatest. There is a slim chance for an isolated t-storm as well
Monday afternoon but with marginal CAPE of 150-400 J/kg and 0-6km
shear less than 15 kts, felt the threat was too low to include in
the forecast at this time. SREF guidance did increase toward 20%
probability for a lightning strike across SE WA and NC ID but the
best sunshine may be in the southwestern Basin...so too early to
call where a rogue strike or two may actually occur.
Temperatures tonight will remain mild and generally above freezing
for most lowlands due to an abundance of cloud cover and light
rain. Highs on Monday will be warming into the upper 40s to 50s
just a few degrees shy of March 27th normal`s. Monday night will
feature a better chance for temperatures to dip in the lower 30s
coupled with patchy fog. /sb
Tuesday through Sunday...Models are in reasonably agreement in
depicting a continued active and progressive spring pattern
featuring at least one and maybe two more good atmospheric river
hosings punctuated by a brief dry interlude.
Tuesday will start out dry and seasonably cool...but the next feed
of deep moisture will become favorably oriented during the day
with an onset of light rain mainly over the mountains north of
the basin and possibly the Idaho Panhandle...but for the most part
Tuesday will be the increasingly cloudy moistening period before
the main event.
Tuesday night and Wednesday...the next atmospheric river will be
favorably directed into the forecast area and enhance into
universal light rain and high mountain snow through
Wednesday...first along a warm front and then along the trailing
cold front. At this time at appears the deep basin will pick up a
third of an inch of rain from this system with amounts increasing
as one moves east culminating in around three quarters of an inch
in the eastern basin zones and Idaho Panhandle valleys...with
around an inch in the mountains but much of this will fall as snow
above 4500 to 5000 feet. this will be good for building up late
season high elevation snowpack especially in the Cascades and
mountains along the Canadian Border.
This further shot of moderate to heavy widespread rain will
likely cause a response on area rivers draining eastern
Washington and north Idaho late this week...possibly delaying the
recession below flood stage on the St. Joe and quite possibly
promoting another minor flood spike on the Little Spokane by
Friday. Other mainstem rivers may rise but levels are now receding
to low enough to handle this storm without flooding. The areal
flood/small stream issues around the region will either be
aggravated somewhat or at least temporarily halted from improving
significantly.
Wednesday night and Thursday...The cold front passage of
Wednesday will herald the arrival of a cool upper level trough
depicted by all the latest model runs. This suggests continuing
showers driving into the Idaho Panhandle...and the possibility of
scattered showers over the eastern half of the forecast area with
a basically dry deep basin in a typical spring-time unsettled
and seasonably cool regime.
Friday and Friday night...The trough moves east and a quiet
upper level ridge takes over providing guarded confidence of a
much needed dry day on Friday.
Saturday through Sunday...Model agreement deteriorates this far
out with the GFS and Canadian models maintaining a flat ridge
over the region...but not the nice and quiet kind of dry ridge.
this will be a ridge which is welcoming another atmospheric river
into it`s westerly flow which implies another round of light
rain...largely skipping the deep basin but enhancing over the
eastern zones and focusing on the northeast and Idaho Panhandle
mountains. The ECMWF model brings a short wave disturbance through
the region. So which ever model is correct...increasing pops for
this period looks quite plausible.
Through the next week the flow regime will remain
progressive...with little opportunity for different transient air
masses to become established. Thus a temperature regime
characteristic of a polar maritime air mass is a safe
bet...warmer than normal low temperatures rarely and only locally
dipping below freezing and slightly cooler than normal high
temperatures impacted by the frequent presence and proximity of
rain or at least significant cloudiness. /Fugazzi
&&
.AVIATION...
00Z TAFs: A warm front followed by a cold front passage shorty
after tonight/tomorrow morning will allow for a prolonged interval
of generally light precipitation over the aviation area. MVFR
ceilings and visibilities associated with the precipitation
(lowland and valley rain with snow generally above 3500 feet MSL)
will linger at times with improvement most likely after 17Z
Monday. /Pelatti
&&
.PRELIMINARY POINT TEMPS/POPS...
Spokane 38 50 34 49 39 50 / 80 40 20 40 60 100
Coeur d`Alene 37 48 34 46 37 49 / 80 70 30 40 50 100
Pullman 38 49 34 49 39 51 / 80 40 20 20 20 100
Lewiston 43 55 37 55 42 56 / 80 40 20 20 10 70
Colville 36 49 32 48 36 49 / 70 30 10 40 60 100
Sandpoint 34 45 33 45 34 46 / 80 60 20 50 50 100
Kellogg 35 45 33 44 34 46 / 90 90 40 40 40 100
Moses Lake 38 57 37 57 42 57 / 80 20 10 10 60 100
Wenatchee 37 54 36 53 38 54 / 70 20 10 20 70 100
Omak 36 53 33 51 38 53 / 90 20 10 30 70 100
&&
.OTX WATCHES/WARNINGS/ADVISORIES...
ID...None.
WA...None.
&&
$$
Area Forecast Discussion...UPDATED
National Weather Service Norman OK
1034 PM CDT Sun Mar 26 2017
.UPDATE...
A few more thunderstorms will remain possible for the next few
hours in far eastern portions of the fa. However, the severe
potential has decreased across the area. A cold front will
continue to move across the area overnight with cooler air moving
into parts of the fa. Adjusted PoPs, hourly grids, and sky cover
have been adjusted to show current trends. Also lowered minimum
temperatures in northern/western parts of the fa where
temperatures are falling behind the front.
&&
.PREV DISCUSSION... /issued 642 PM CDT Sun Mar 26 2017/
DISCUSSION...
AVIATION...
Severe thunderstorms are expected to move east away from OKC this
evening while other strong or severe thunderstorms move across the
OK-KS border area toward PNC later this evening. A cold front will
sweep northwest to southeast overnight shifting winds to
northwest. MVFR ceilings are expected to follow until around mid-
day Monday. VFR conditions and lighter winds will arrive Monday
afternoon.
PREV DISCUSSION... /issued 258 PM CDT Sun Mar 26 2017/
DISCUSSION...
Cirrostratus continues to stream overhead this afternoon ahead of
the mid to upper low currently centered over SW KS. A few elevated
storms developed within nose of low level moisture plume/WAA over
central OK around 1 PM and have moved east of I35 now. Both the
previously mentioned cloud cover and early moist convection will
have an impact on instability for late this afternoon through this
evening. However, despite cloud cover some CU can be seen through
thin cirrus from near Chickasha to Lawton where an instability
axis resides. This instability axis should slowly start to expand
north and eastward through the late afternoon hours as height
falls commence. The HRRR continues to indicate rapid development
will occur along/ahead of the dryline around 23Z across central
and south central OK. Very large hail and damaging wind gusts over
70 mph (especially east of I35 later this evening) will be
possible. In addition, ~850 mb flow will begin to veer this
evening increasing low level shear specifically along the I35
corridor. LCLs will also continue to lower as dewpoints climb
into the low 60s. Expect highest tornado potential to be some
time around 23-02Z this evening. The storms should quickly exit
our eastern zones before 06Z tonight.
A subtle cold front will accompany the mid to upper low late
tonight through tomorrow morning, with some dry air advection. It
will be a beautiful day tomorrow under the influence of a weak
surface ridge, although some stratus may try to liner over the NE.
The low level flow will then quickly return from the SE Tuesday as
the next upper low traverses the four corners region. A fairly
sharp dryline is expected by Tue afternoon from the NW panhandles
into western north TX. Stout WAA and accompanying stratus may
limit the severe potential Tue to a narrow axis over the SW. Later
through the evening Tue, widespread showers and thunderstorms are
expected with the approach of the closed low. This low will slowly
meander over the central and southern plains through Thu, which
could bust some of the drought. Some locations could receive over
3 inches of rainfall through late Thu. A brief break in rain
chances will occur on Friday before yet another, even deeper,
closed low passes over the southern plains.
&&
.PRELIMINARY POINT TEMPS/POPS...
Oklahoma City OK 52 70 48 71 / 20 0 0 40
Hobart OK 47 71 49 67 / 10 0 0 60
Wichita Falls TX 50 75 52 74 / 0 0 0 50
Gage OK 42 71 47 60 / 20 0 0 70
Ponca City OK 48 67 45 69 / 60 10 0 20
Durant OK 58 75 51 75 / 60 0 0 20
&&
.OUN WATCHES/WARNINGS/ADVISORIES...
OK...None.
TX...None.
&&
$$
25/09
Area Forecast Discussion
National Weather Service Charleston WV
935 PM EDT Sun Mar 26 2017
.SYNOPSIS...
Active, mild pattern continues in a parade of southern stream
systems. One crosses this evening, followed by another Monday
night and Tuesday, and then again Thursday through Friday.
&&
.NEAR TERM /THROUGH MONDAY/...
As of 920 PM Sunday...
Took out thunder for entire area before midnight. Rain showers
gradually decreasing from southwest to northeast after midnight,
confined to far northeast WV by morning.
As of 2 PM Sunday...
The remainder of the afternoon will tell what comes of a
negatively tilted trough axis pivoting through the middle Ohio
Valley, and the left front exit region of a strong jet on the
back side of the trough coming in close proximity of the
diffluent area ahead of the trough axis.
So far, only small breaks in the cloud cover have limited
surface heating. Heating was more evident farther south, beneath
and behind the upper level trough axis, where the first
thunderstorms were firing up in eastern Kentucky early this
afternoon. The WRFs appear to have this pegged as the beginning
of the main shower/thunderstorm activity crossing the area this
afternoon into this evening, as the categorical PoPs in the
forecast depict.
The low level reflection of the upper level trough is a warm
occlusion that will push through the area tonight. Loss of
daytime heating should end the thunderstorm threat tonight,
while the last of the showers should end once the occlusion
pushes through. Compromised between the faster GFS, HRRR and
RUC, and slower NAM and WRFs in winding down the precipitation
overnight tonight. Models depict morning stratus where the
surface occlusion stalls over the middle Ohio Valley on Monday.
The next short wave trough brings an increasing chance for
showers and thunderstorms from the southwest late Monday.
Used a blend of near term guidance for temperatures and dew
points, which did not bring up any major changes from the
previous forecast.
&&
.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY NIGHT/...
As of 4 PM Sunday...
Upper level southern stream short wave trough crosses Monday
night and Tuesday, bringing the next round of showers and
thunderstorms. However, the timing of the system is such that
the strongest thunderstorms will be to the west of the forecast
area Monday afternoon, and then to the east on Tuesday
afternoon.
The system pulls out Tuesday afternoon and evening, but is
likely to leave low level moisture behind in the form of stratus
overnight Tuesday night into Wednesday morning. High pressure
sails across to the north of the area Wednesday, followed by a
southeast flow developing in its wake by Thursday morning,
beneath an upper level ridge.
Temperatures close to central guidance and remaining above
normal, even in the wake of the system midweek.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
As of 4 PM Sunday...
The next southern stream upper level low approaches Thursday
through Friday, before passing north of the area Friday night.
This brings a surface warm front, along with an initial round
of rain or rain showers, Thursday afternoon and evening.
The surface cold front crosses Friday evening, as the surface
low passes north of the area Friday night. Models have come in
good agreement on this system. Showers and thunderstorms are
most likely Friday into Friday night, but with the typical
downslope shadow effect west of the mountains Friday in strong
south to southeast flow in the warm sector ahead of the cold
front.
Northwest flow behind the system may bring upslope rain showers
in and near the WV mountains on Saturday, with the latter part
of next weekend more likely to bring dry weather. However,
models are not too divergent on timing of yet another southern
upper level low approaching late next Sunday.
Temperatures close to central guidance and lower than the MEX.
&&
.AVIATION /02Z MONDAY THROUGH FRIDAY/...
As of 920 PM Sunday...
An upper level disturbance will continue to bring showers into
the night time hours, mostly ending from southwest to northeast
by around 13Z Monday. Thunder potential will mostly dissipate
by 03Z with loss of heating. Look for brief MVFR/IFR VSBY in a
few of the heavier rain showers.
15 to 20 kts of southerly flow just above the surface should
generally keep IFR fog from becoming an issue. However,
prevailing VFR ceilings become MVFR ceilings after 06Z, but
with locally IFR ceilings possible mainly higher mountains. No
IFR is forecast for major TAF sites overnight. Expect clouds
lifting to VFR ceilings 3500-4500 feet by 15Z Monday.
The rest of Monday will bring dry VFR weather, with at most a
4-6kft stratocu deck.
Surface flow will become light south tonight, and then southerly
5 to 8 kts Monday afternoon.
FORECAST CONFIDENCE AND ALTERNATE SCENARIOS THROUGH 00Z TUESDAY...
FORECAST CONFIDENCE: Medium
ALTERNATE SCENARIOS: There may be a bit more IFR ceilings
overnight and early Monday morning, and timing of improvement
to VFR on Monday may vary.
EXPERIMENTAL TABLE OF FLIGHT CATEGORY OBJECTIVELY SHOWS CONSISTENCY
OF WFO FORECAST TO AVAILABLE MODEL INFORMATION:
H = HIGH: TAF CONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
M = MEDIUM: TAF HAS VARYING LEVEL OF CONSISTENCY WITH MODELS.
L = LOW: TAF INCONSISTENT WITH ALL MODELS OR ALL BUT ONE MODEL.
DATE MON 03/27/17
UTC 1HRLY 00 01 02 03 04 05 06 07 08 09 10 11
EDT 1HRLY 20 21 22 23 00 01 02 03 04 05 06 07
CRW CONSISTENCY H H H H H H H H H H M L
HTS CONSISTENCY H H H H H H H H M M M L
BKW CONSISTENCY H H H H H H H M M M M L
EKN CONSISTENCY H H H H H M M M M M M M
PKB CONSISTENCY H H H H H H H H H L L M
CKB CONSISTENCY H H H H H H H H M M M L
AFTER 00Z TUESDAY...
Brief IFR possible in thunderstorms Monday night and Tuesday.
&&
.EQUIPMENT...
Radar site KRLX appears to have a faulty component that is
leading to higher reflectivities than what should be observed at
times. So far today and this evening, however, the radar has
performed normally. Further evaluation and monitoring is
expected prior to action being taken.
&&
.RLX WATCHES/WARNINGS/ADVISORIES...
WV...None.
OH...None.
KY...None.
VA...None.
&&
$$
SYNOPSIS...TRM
NEAR TERM...JMV
SHORT TERM...TRM
LONG TERM...TRM
AVIATION...JMV
EQUIPMENT...99
Area Forecast Discussion
National Weather Service Blacksburg VA
710 PM EDT Sun Mar 26 2017
.SYNOPSIS...
Low pressure near Chicago will move northeast through the Great
lakes and weaken as it passes into Ontario tonight and Monday.
A second area of low pressure will move northeast out of the
southern Plains crossing the Mid-MS Valley Monday, and across
the Ohio Valley into the northern Mid-Atlantic Monday night and
Tuesday. These weather features will result in unsettled weather
across the central and northern Appalachians through Tuesday.
Temperatures will remain well above normal through mid week.
&&
.NEAR TERM /THROUGH MONDAY/...
As of 659 PM EDT Sunday...Radar and METARs continue to indicate
ongoing, though weakening rain showers from Roanoke to
Reidsville NC eastward into western portions of Appomattox
County. These showers stand to dissipate per recent HRRR/NAMNest
output. Also watching stronger convective development to the
the west and south of our forecast area, primarily in central
West Virginia, associated with vort max pinwheeling northeast
into southern Ohio around parent upper trough extending
southeastward from the upper Midwest. Past couple HRRR runs,
which have generally handled the spatial coverage of convection
to our west the best since it partly initializes off radar,
continues to suggest that some possible scattered
showers/possible rumble of thunder may slip into Mercer, Summers
and western Greenbrier Counties in WV as well as our southwest
Virginia Tennessee Valley counties next couple hours. As we
progress toward midnight, upper trough lifts to our northeast,
leaving us in shortwave ridging overnight. As forcing becomes
nebulous at best, except for some additional upslope convergence
along the southern Blue Ridge, PoPs should be at their lowest
overnight with shower coverage being even more isolated than
they presently are. Given rather saturated air mass would expect
skies to stay at least mostly cloudy. Lows only fall into the
50s tonight.
Previous near-term discussion issued at 300 PM follows...
Radar indicated a 30 mile wide band of rain showers propagating
east across the central CWA. As of 3PM the leading edge was
along the 220 corridor from Clifton Forge to Martinsville.
Movement was to the east at 20 mph.
Leading rain band was associated with a front aloft, arcing from
NW to SE from Low pressure moving through the Great Lakes.
The actual surface front was over western KY/TN, with additional
bands/clusters of showers and thunderstorms scattered across the
Ohio Valley. The initial rain band over our CWA has outrun any
surface instability and has been weakening with time. Rainfall
amounts have been averaging between a tenth to a quarter of an
inch, but as this band of showers continues to move east, the
overall qpf will diminish with amounts of a tenth of an inch or
less. Timing suggests these showers will reach Highway 29
corridor...Charlottesville, Lynchburg, Danville, between 5-6PM.
Behind the front aloft, some partial clearing was taking place,
the rain only lasting a couple hours in duration. Once this
initial rain area moves east, will have to wait for the
instability driven showers over KY/TN ahead of the actual
surface front to move east. Models suggest most of this activity
will dissipate during the overnight, but until then will
threaten our western CWA (primarily west of I-77 in VA/NC and
west of Lewisburg or highway 219 in WV) this evening with
potential for both showers and thunderstorms and an additional
tenth or two of rainfall before midnight.
As the main upper level low slides by to our northwest overnight,
dynamic support will decrease. The actual surface front is
forecast to wash out before crossing the mountains so this will
maintain a persistent mild southerly flow across the forecast
area overnight. As such, there will be a continued chance of
showers mainly along and west of the Blue Ridge overnight,
although nothing severe per waning instability. Some patchy fog
is also possible, but cloud cover should prevent it from
becoming widespread.
On Monday, a second storm system will be moving northeast out
of the southern Plains, crossing the Mid MS valley during the
day and into the OH Valley Monday evening. Response will be the
development of more showers and thunderstorms with focus
primarily to our west across the OH/TN valleys. Model soundings
suggest some instability driven activity may develop over our
CWA during the afternoon associated with weak convergence near
the Blue Ridge. Attm will advertise chance threat for
showers/storms Monday, but coverage generally less than 50
percent and no mention of severe attm. Certainly can`t rule out
a stronger storm or two if temperatures rise into the 70s permitting
surface based CAPE in the 1000-1500 range.
Temperatures through Monday will remain mild with readings 10
to 15 degrees above normal, and remaining well above freezing.
&&
.SHORT TERM /MONDAY NIGHT THROUGH WEDNESDAY NIGHT/...
As of 300 PM EDT Sunday...
During this portion of the forecast, a Pacific based system is
expected to impact the region. Guidance among the models is in good
agreement of bringing a shortwave trough eastward along the Ohio
Valley and then into the New York City region Monday night into, and
through Tuesday. This track will keep the region on the mild side of
the system until the passage of its associated cold front Tuesday
morning into the afternoon hours.
Scattered showers and isolated storms across the area Monday
afternoon, will lingering into Monday evening. The scattered showers
will continue through the overnight, with coverage increasing
towards daybreak in the west. There may be an initial increase in
coverage across eastern parts of the area through the evening hours,
but decrease to isolated coverage early Tuesday morning.
As the front crosses the region on Tuesday, showers will be in
greatest concentration coincident and just in advance of the cold
front. Instability is progged to increase enough to warrant isolated
to scattered thunderstorms in this same general area, with the best
potential shifting eastward during the course of the day.
Coverage will quickly decrease Tuesday evening with the departure of
the cold front to the east. Some lingering northwest flow upslope
isolated showers are possible across portions of southeast West
Virginia, neighboring counties of southwest Virginia, and south into
the Northern Mountains of North Carolina. Coverage will be greatest
during the evening hours with decreasing coverage as the nigh
progresses.
Wednesday into Wednesday night, an upper level shortwave ridge is
progged to build over the area, all while surface high pressure
noses south along the lee of the Appalachians. Look for any
lingering isolated showers in the west to end by noon. Limited cloud
cover is forecast for all of the region by Wednesday afternoon. As
Wednesday night progresses, low level flow on the west side of the
surface ridge will allow for moisture levels to increase. Anticipate
increasing cloud cover, and eventually some patchy light rain across
areas mainly near the crest of the Blue Ridge from roughly Roanoke,
VA southwest into the Northern Mountains of North Carolina.
Temperatures during this portion of the forecast will trend from
roughly fifteen degrees above normal Monday night into Tuesday to
around five to ten degrees above normal Wednesday into Wednesday night.
&&
.LONG TERM /THURSDAY THROUGH SUNDAY/...
As of 300 PM EDT Sunday...
The lee side ridge of surface high pressure will continue to prevail
on Thursday, although low level flow not too far above the surface
will start to increase as a closed upper low heads eastward through
the central U.S. Look for light rain to increase across the area on
Thursday, especially western and central parts of the region. The
activity will take on more of a showery nature Thursday night as the
upper system draws closer.
On Friday, showers will be likely across most of the region with
isolated thunderstorm possible across the western and southern parts
of the area. The main system will track north of the area Friday
night into Saturday, with its associated cold front across our
region early Friday night. Look for an end of the shower activity
for much of the area by Saturday morning. Lingering upslope showers
on the backside of the system will be possible across southeast West
Virginia and neighboring counties of southwest Virginia.
Saturday night into Sunday, an upper level ridge will build over the
area, allowing for a gradual decrease in the upslope showers in the
west, and limited cloud cover in the east.
Temperatures during this portion of the forecast will be around or
slightly above normal Thursday and Friday, but trend to readings
about ten degrees above normal for Saturday and Sunday.
&&
.AVIATION /00Z MONDAY THROUGH FRIDAY/...
As of 710 PM EDT Sunday...
VFR to VFR/MVFR presently across most of the terminals, and
those conditions should continue through the next couple of
hours. Of note is lower, more widespread MVFR ceilings along the
southern Blue Ridge and into the NC mountains that will
contribute to obscured mountains through much of the TAF period.
Ongoing unrestricted showers from Roanoke and Lynchburg south to
Danville and Reidsville should persist next couple of hours as
well. Limited potential for in-cloud lightning in southeast WV
next couple hours, but not expected to affect any TAF.
Confidence in ceilings is low for the rest of the overnight, but
expect OVC VFR to MVFR to be the primary ceiling conditions for
the terminals. Generally reflected this uncertainty with a
second SCT MVFR cloud group. Light south to southeast winds
overnight.
For Monday...ceilings should begin to become scattered to broken
again. Potential for showers and thunderstorms again for
tomorrow, though would tend to be sporadic/intermittent. Winds
stay southerly around 6-10 kts.
Extended Aviation Discussion...
An active weather period with a series of vigorous upper-level
low pressure areas tracking from west to east across the U.S.
during the week. Areas of sub-VFR cigs/vsbys are possible,
especially during the morning hours, in low clouds and fog.
Coverage of showers and thunderstorms will be the greatest
during the afternoon and evening coinciding with the peak
heating of the day.
&&
.RNK WATCHES/WARNINGS/ADVISORIES...
VA...None.
NC...None.
WV...None.
&&
$$
SYNOPSIS...PM
NEAR TERM...AL/PM
SHORT TERM...DS
LONG TERM...DS
AVIATION...AL/PM