Forecast Discussions mentioning any of
"HRRR" "RAP" "RUC13" "RUC" "RR" received at GSD on 03/09/17
Area Forecast Discussion
National Weather Service Austin/San Antonio TX
535 PM CST Wed Mar 8 2017
.AVIATION...
MVFR CIGs have spread into the San Antonio area will eventually
spread to Austin and Del Rio. CIGs and VIS will drop further to IFR
later this evening and overnight. Improvement Thursday will slow with
MVFR likely by late morning and VFR by mid-afternoon.
&&
.PREV DISCUSSION... /ISSUED 336 PM CST Wed Mar 8 2017/
SHORT TERM (Tonight through Thursday Night)...
Temperatures have warmed up nicely into the upper 60s to mid 70s for
most of the region despite relatively few breaks in the clouds this
afternoon, with only a few spots along the Edwards Plateau remaining
in the mid 60s where clouds have not broken out. Weak warm air
advection and relatively strong moisture advection continue across
the region north of a dissipating frontal surface located near Laredo
and Corpus Christi, resulting in dewpoints increasing into the mid
50s to lower 60s. Gravity waves are also now visible on satellite
imagery as previously suspected given some wavy cloud features seen
by many across the region. These features suggest the boundary layer
inversion is robust enough to prevent deeper convection from
developing, but a few model soundings suggest some more surface-
based instability may be realized for a brief window late this
afternoon and early evening. In addition, the HRRR generates some
convective showers and perhaps a rogue thunderstorm along the I-35
corridor from San Antonio to San Marcos. Thus, have left in a slight
chance of showers and thunderstorms over these areas and the Rio
Grande Plains through 9 pm, but this is a very conditional threat.
Showers should end this evening with the main weather impact for
tonight being patchy to widespread advection fog as low temperatures
only dip into the lower 60s for most areas given continued moisture
and warm air advection. Winds should remain southerly at 5 mph to
keep the threat for dense fog relatively low aside from localized
low-lying areas, but if calm conditions develop this could become a
bit more widespread particularly over the Edwards Plateau. All fog
should lift by mid-morning, but clouds should persist for most of the
day similar to today given the weak, but broad isentropic ascent and
moisture over the region. Temperatures should warm up into the mid
to upper 70s tomorrow as any frontal remnants to the south should
completely dissipate. Similar to today, isolated to scattered showers
should generally remain over the Rio Grande Plains and southern
counties, but a few brief thunderstorms cannot be ruled out in the
late afternoon and evening, particularly in the Rio Grande Plains.
LONG TERM (Friday through Wednesday)...
The current zonal flow pattern aloft will become more amplified
through Friday as the broad upper level trough off the coast of Baja
California slowly slides to the east. The ECMWF consistently develops
a weak leading shortwave compared to the GFS which has a weaker
representation of this feature, but both models support a back door
cold front approaching the region from the northeast Friday afternoon
and evening. This additional surface forcing should result in more
scattered to widespread showers and thunderstorms across the area,
but have still kept POPs in the 30-50 percent range due to timing
issues. The hi-res Texas Tech WRF depicts more widespread showers
and thunderstorms approaching from the southwest, giving confidence
to the ECMWF solution with the stronger leading shortwave, so POPs
remain elevated through Friday night into Saturday. High temperatures
should remain in the mid to upper 70s unless the front holds
together into our area and keeping temperatures on Saturday.
A stronger shortwave digging into northeast Texas and Louisiana
should help push a front through the region late Saturday night into
Sunday morning. Model agreement is fairly good on this timing, but
rainfall coverage varies a bit more as the best dynamics will
probably be to our northeast which will have better upper-level
divergence closer to the right entrance region of the polar jet and
the left exit region of the subtropical jet. Northerly winds should
help filter in drier air behind the front to allow for one day of
below normal high temperatures in the 60s with partly cloudy skies. A
gradual warm up begins Monday for next week despite northwest flow
aloft and northerly flow at the surface being reinforced by a weak
front that quickly moves through on Tuesday.
&&
.PRELIMINARY POINT TEMPS/POPS...
Austin Camp Mabry 64 79 66 79 63 / 10 20 20 40 30
Austin Bergstrom Intl Airport 65 79 66 79 64 / 10 20 20 40 30
New Braunfels Muni Airport 64 79 65 78 64 / 20 20 20 40 30
Burnet Muni Airport 60 77 63 75 60 / 10 20 20 30 30
Del Rio Intl Airport 63 79 63 78 61 / 20 30 30 30 30
Georgetown Muni Airport 62 78 64 77 62 / 10 20 20 40 30
Hondo Muni Airport 62 79 63 79 62 / 30 20 20 40 30
San Marcos Muni Airport 64 79 66 79 63 / 20 20 20 40 30
La Grange - Fayette Regional 64 79 66 79 64 / 20 20 20 50 40
San Antonio Intl Airport 65 79 65 79 64 / 20 20 20 40 30
Stinson Muni Airport 65 79 66 79 65 / 20 20 20 40 40
&&
.EWX WATCHES/WARNINGS/ADVISORIES...
None.
&&
$$
Mesoscale/Aviation...05
Synoptic/Grids...Allen
Public Service/Data Collection...33
Area Forecast Discussion
National Weather Service Goodland KS
400 PM MST Wed Mar 8 2017
.SHORT TERM...(This afternoon through Thursday)
Issued at 112 PM MST Wed Mar 8 2017
Early afternoon WV imagery and RAP upper level analysis shows a long
fetch of west northwest flow from the Pacific Northwest, across the
Central High Plains, and into the Central Mississippi River Valley.
At the surface, high pressure is retreated east though it is still
holding influence over our eastern CWA. Lee trough has developed,
however tighter gradient is limited to our NW CWA closer to low
pressure center.
This afternoon (regarding RFW): With weaker surface gradient and
much weaker winds aloft than some guidance had indicated winds have
remained relatively light and variable. There have been increasing in
our NWS and the BL maxima should transition eastward was lee trough
continues to deepen based on latest RAP trends. Even with this RAP
though the window may be closing and the period where we could see
these winds (20-23kt) mix to the surface will be past peak heating
(less likely to tap into this layer then). Confidence we will see
3hr or 25 mph gusts in area of RFW has greatly diminished, but I am
hesitant to make chances as RH values have been in the 14-16% range
and I can`t rule it out yet. No changes planned to RFW at this time,
though we may be able to end it early once we get past peak heating.
West to northwest flow aloft persists tonight, with ridging
developing over the western US Thursday. This pattern will support
continued dry conditions over our CWA through Thursday as a deep dry
air mass persists over the Central High Plains. Lows tonight will be
a little warmer than previous night due to the change in air mass,
and guidance is showing most locations in the 30s. With less wind
and good radiational conditions I could still see a few locations
drop into the 20s overnight.
A shortwave trough will round the large
scale upper low and pass over the northern Mississippi River valley
and kick a backdoor cold front towards our CWA Thursday. Head of
this front will will still see a warmer air mass, and may have a
better period of WAA than current models are indicating. Guidance
continues to support high temps around 70F, and we could see highs
approach the mid 70s in our south deepening on magnitude of
prefrontal WAA.
.LONG TERM...(Thursday night through Wednesday)
Issued at 155 PM MST Wed Mar 8 2017
The extended period starts off with a broad west-northwest flow
aloft across the CONUS while a large and intense upper low holds
over Hudson Bay. A minor embedded trough aloft will slide
southeast across the Central High Plains early Saturday, but the
timing and lack of deep moisture will preclude anything but a
mention of a slight chance of precipitation. Temperatures will
remain above normal in the 50s and 60s for afternoon highs through
Sunday.
Late in the weekend the upper low over Hudson Bay will amplify and
send a couple stronger troughs rotating down into the Mississippi
and Ohio Valleys. This will build an upper ridge in the West and
develop a deepening trough in the East which will bring a Canadian
airmass south into the Plains Monday and Monday night. This will
be a quick push of cold air which will modify rapidly Tuesday and
Wednesday of next week. Guidance differs in the timing and intensity of
upper trough passage with the ECMWF faster than the GFS which
makes forecast timing uncertain. Better chances for any light
precipitation occurring would be in the Sunday night to Monday
night timeframe, and mainly across the northeast half of the
forecast area.
After a quick cool down Monday with highs in the 40s and 50s,
readings will rebound into the 60s areawide by Wednesday.
&&
.AVIATION...(For the 00Z TAFS through 00Z Thursday evening)
Issued at 400 PM MST Wed Mar 8 2017
Conditions...VFR with SCT200-250.
Precip/Wx....None expected.
Winds........For KGLD...SW around 10kts thru 11z Thursday...then
W around 10kts. By 15z Thursday...N around 10kts. For MCK...W
around 10kts thru 16z Thursday...then NNW around 10kts.
&&
.GLD WATCHES/WARNINGS/ADVISORIES...
KS...Red Flag Warning until 5 PM MST /6 PM CST/ this afternoon for
KSZ001>004-013-014.
CO...Red Flag Warning until 5 PM MST this afternoon for COZ252-253.
NE...Red Flag Warning until 5 PM MST /6 PM CST/ this afternoon for
NEZ079>081.
&&
$$
SHORT TERM...DR
LONG TERM...DLF
AVIATION...JN
Area Forecast Discussion
National Weather Service Green Bay WI
524 PM CST Wed Mar 8 2017
Updated aviation portion for 00Z TAF issuance
.SHORT TERM...Tonight and Thursday
Issued at 235 PM CST Wed Mar 8 2017
The latest rap analysis and satellite/radar imagery show a tight
pressure gradient remains in place between strong low pressure over
southern Hudson Bay and high pressure across the Plains. Strong
gusty winds as a result of this pressure gradient appeared to have
peaked during the morning when a few isolated gusts near 60 mph
occurred. Still though, potential will remain for wind gusts
between 50 and 55 mph over central and east-central WI into early
this evening. Snow showers and flurries have also diminished across
the area as well, as retreating clouds have yielded increasing
sunshine over central and east-central WI. This trend should
continue for the rest of the afternoon. Looking upstream, the next
area of clouds is pushing southeast over the Dakotas. Forecast
concerns include the strong gusty winds into this evening, followed
by small snow chances on Thursday morning.
Tonight...Though a surface ridge axis will be lifting northeast
towards the area, a tight pressure gradient up to 850mb will ensure
the strong gusty winds will linger into early this evening.
However, progged soundings indicate that inversion heights will
lower to below 900mb due to increasing subsidence, which
should lead to a diminishing wind trend this evening. As a result,
think that will let the wind advisory go on until the expiration
time. Otherwise, should see a period of mostly clear conditions
this evening before clouds increase from the west once again ahead
of channeled vort energy. This energy combined with a low level
thermal gradient may produce a narrow band of light snow which could
move into southwest WI towards daybreak. Both the nam and arw show
this narrow area of snow approaching central WI, so some uncertainty
with the track, and will include a slight chance of snow from
southern Wood to southern Winnebago counties. Temps falling into
the upper single digits in the north to the middle 20s in the south.
Thursday...The small chance of light snow will linger over the
southern Fox Valley during the morning before the mid-level
convergence slides to the southeast. If the track of the snow does
shift north, perhaps a half inch of accumulations would be possible.
Should see decreasing clouds in the afternoon as the weak system
pulls away with highs ranging from the upper 20s in the north to
middle 30s in the south.
.LONG TERM...Thursday Night Through Wednesday
Issued at 235 PM CST Wed Mar 8 2017
West-northwesterly flow aloft and surface winds from the
northwest to north will stay around through much of the weekend and
into Sunday, resulting in below normal temperatures through the
period. Minimal active weather is expected through this period with
the exception of the far north, which may see a few additional lake
effect snow showers. Temperatures in the north may dip to around
zero for a brief period on Friday morning, coinciding with a few
stronger breezes for negative wind chills around -10 to -20. Wind
chills will likely be a bit warmer in central and east-central
Wisconsin as guidance may still be a touch cool, thanks to a lack of
snowcover.
A more widespread precipitation event will arrive Sunday night into
Monday as a clipper system passes over the area. The exact track of
highest snow totals is still unclear as models disagree on the
degree of influence of the surface high behind the upper trough;
however, widespread snowfall is expected across the region. Models
continue to push for a more southerly track for the low pressure
system with weaker warm air advection, which ultimately continues a
trend of pushing any threat of mixed precipitation out of Wisconsin.
Quiet conditions then return briefly towards the middle of next week.
After the below normal temperatures through the weekend, readings
will return closer to normal early next week.
&&
.AVIATION...for 00Z TAF Issuance
Issued at 524 PM CST Wed Mar 8 2017
Strong and gusty west winds sustained from 15 to 25 knots with
gusts to 35 to 45 knots will be possible through early this
evening. This will produce crosswind considerations at some
airports. Winds will diminish significantly early this evening
with light winds expected later tonight. Other than the winds, VFR
conditions are expected across the TAF sites with with mostly
clear skies tonight. A weak clipper should pass by south of the
taf sites Thursday morning. This should only bring some mid clouds
to the TAF sites Thursday morning with a small chance of snow
across the southern forecast area.
&&
.GRB WATCHES/WARNINGS/ADVISORIES...
Wind Advisory until 7 PM CST this evening for WIZ005-010>013-
018>022-030-031-035>040-045-048>050-073-074.
&&
$$
SHORT TERM.....MPC
LONG TERM......Uhlmann
AVIATION.......Kurimski
Area Forecast Discussion
National Weather Service Melbourne FL
822 PM EST Wed Mar 8 2017
.DISCUSSION...
Current...Two areas of interest over the next few hours relative
to precipitation chances. One clustered up over Volusia County as
part of a meager pre-frontal band segment. The second in vicinity
if I-4 with boundary merger interactions, but likely not very
productive. The HRRR likes an isolated shower chance for both
areas before the modest shifting in focus to the Space and
Treasure Coasts for the overnight. Yet, with the winds slackening
off, that too is no more than an isolated stretch. A general
dampening of convection overall so PoPs remain modest and grids
will undergo only minor tweaks as operational relevance is
essentially unchanged. Front slowing and thinning over CFL.
&&
.AVIATION...Mostly VFR with lowest ceilings BKN040-060 overnight,
especially in proximity of VCSH with pre-frontal band sagging
into Central Florida. Otherwise, chance for 3-5SM BR for inland
sites as winds become 05KT or less. Front sags to South Florida by
00Z.
&&
.MARINE...Southerly winds are expected this evening with north
wind developing after midnight behind the sagging frontal
boundary. Swells will continue to subside some into late tonight
with seas 3 ft near shore to around 4 ft offshore.
&&
.PRELIMINARY POINT TEMPS/POPS...
DAB 62 78 58 82 / 20 20 10 20
MCO 64 83 60 84 / 20 20 10 10
MLB 63 80 60 83 / 20 30 10 10
VRB 61 80 59 83 / 20 30 10 10
LEE 62 83 61 83 / 20 10 10 10
SFB 62 82 60 84 / 20 20 10 10
ORL 65 82 61 83 / 20 20 10 10
FPR 59 80 57 83 / 20 20 10 10
&&
.MLB WATCHES/WARNINGS/ADVISORIES...
FL...None.
AM...None.
&&
$$
SHORT TERM...DS
LONG TERM....RL
Area Forecast Discussion
National Weather Service Tulsa OK
918 PM CST Wed Mar 8 2017
...UPDATE...
.DISCUSSION...
Mostly clear skies along with light southerly winds were common
across Eastern Oklahoma and Northwest Arkansas this evening.
However...to the south across Texas...low level moisture with 50+
degree dewpoints and cloud cover were streaming northward within
the low level flow. This moisture and cloud cover increases are
expected to push into Eastern Oklahoma overnight and over the CWA
Thursday ahead of an approaching frontal boundary...currently over
the Central Plains and Midwest.
In response to the increasing moisture/cloud cover...temperatures
overnight tonight are forecast to remain warmer compared to last
night. Lows in the 40s for most locations are forecast with 50s
possible over Southeast Oklahoma...where greater cloud cover
should be located by Thursday morning. Thus...have added minor
tweaks to temp/dewpoint grids and adjusted sky grids to account
for latest trends.
Latest Rap model runs have tried to indicate some light precip
developing over parts of the region late tonight, while the HRRR
and other short term guidance keeps precip development mainly south
and west of the CWA before 12z. For now will continue with
current forecast and leave precip mention out for tonight with
increasing chances during the day Thursday.
&&
.PRELIMINARY POINT TEMPS/POPS...
TUL 49 77 44 62 / 0 20 20 10
FSM 47 77 53 68 / 0 10 40 10
MLC 51 75 54 68 / 10 10 40 20
BVO 41 78 39 59 / 0 20 20 10
FYV 40 73 46 61 / 0 20 50 10
BYV 47 75 43 57 / 0 30 60 10
MKO 48 77 49 65 / 0 10 30 10
MIO 45 76 40 58 / 0 30 30 10
F10 50 76 49 64 / 0 10 20 10
HHW 55 73 57 71 / 10 20 40 30
&&
.TSA WATCHES/WARNINGS/ADVISORIES...
OK...None.
AR...None.
&&
$$
SHORT TERM...20
AVIATION.....07