Area Forecast Discussion
Issued by NWS Dodge City, KS

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FXUS63 KDDC 290902

402 AM CDT Tue Jul 29 2014

...Updated Short Term and Long Term sections...

.SHORT TERM...(Today and tonight)

A significant, excessive rainfall event appears more and more likely
across portions of southwest, west central, and south central
Kansas. lower-mid tropospheric frontogenesis will increase
substantially in the 00-06Z Wednesday time frame, thanks to coupling
dynamics for ascent from the exiting Midwest jet and perturbed
monsoon flow from northern Arizona rotating anticyclonically into
Colorado. There was a fairly well-defined vorticity anomaly moving
north-northeast into southern Utah, with greatest area of potential
vorticity advection (and subsequent mid-tropospheric ascent) moving
into western Colorado as of 08Z this morning. Every numerical
weather prediction we can get our hands on shows the same thing: a
swath of 2 to 5 inches of storm total QPF, with much of it falling
in the 06-18Z time frame Wednesday. The question still remains where
the important 850-750mb mean frontogenesis will set up. There has
been a slight trend to the north with the frontogenetic zone in the
GFS and now the latest 29.06Z run of the NAM12.

There are a couple things that are concerning for a flood/flash
flood threat: 1) the monsoon influence. Water vapor satellite loop
shows a fairly large area of fairly high content water vapor
(tropical in nature) all across the Desert Southwest into the
Southern Rockies and into far western Kansas. 29.00Z RAOB at Grand
Junction, CO and Albuquerque, NM both show deep tropical moisture
up above 500mb (500mb mixing ratio at or just above 4 g/kg). 2)
orientation of 750-850mb zone of frontogenesis with deep
tropospheric mean flow. The frontogenetic zone will setup in a
west-northwest to east-southeast orientation during the time frame
in question late tonight through the first half of Wednesday,
which will be nearly parallel to the 850-300mb thickness field,
which is usually a good indication of MCS motion in this
environment. Training of storms in a high-precipitation effeciency
environment is definitely a strong possibility. This will
certainly lead to some areas seeing excessive rainfall over a short
period of time. Per collaboration with AMA, OUN, and PUB, we
decided to all join in on a Flash Flood Watch. The official QPF
grids will reflect storm total amounts in excess of 2 inches over
a large portion of the area south of roughly a Scott City to
Jetmore to Pratt line. There will likely be a band or two of 4 or
even 5-inch amounts when all is said and done, but this level of
detail cannot be forecast at this time. All indications are that
the atmosphere will be capable of this excessive rainfall total,
though, and we will mention this in the Flash Flood Watch product.

.LONG TERM...(Wednesday through Monday)

Little overall change was made to the forecast elements in the days
2 and 3 timeframe with respect to the meteorological elements.
Following the models, some downward adjustment in PoPs was made for
Wednesday afternoon when convection and stratiform rain should be
winding down across south central Kansas as the mid level
frontogenetic zone weakens and moves south of the region. The GFS
advertises the highest amount of QPF, on the order of 3 to 5 inches
on Wednesday, which could easily be achievable with training storms
in this MIDLEVEL tropical relatively warm collision-coalescence
environment. The consensus of models continue to indicate cool
temperatures  in the the upper 60`s where the heaviest deep cloud
layer produces rain cooled air through the day.  Beyond Wednesday,
the region will be under the influence of northwest flow aloft with
a signal for late afternoon convection along the Palmer divide and
sangre de cristo mts, occasionally moving into extreme sw Kansas by
early evening. High temperatures should moderate through the 80s
though the weekend and into next week.


.AVIATION...(For the 06Z TAFS through 06Z Tuesday night)

Light winds will continue through the night and into the morning
hours Tuesday, with winds increasing to 12 to 15 knots thereafter
from the south-southwest. The best precipitation chances will hold
off until Tuesday evening, and we will introduce some PROB30
thunderstorms for DDC and GCK terminals at the end of the forecast
period (Tuesday evening).


DDC  81  63  68  60 /  30 100  90  50
GCK  81  63  69  57 /  30 100  90  40
EHA  77  62  72  60 /  40  90  70  40
LBL  78  63  72  61 /  30 100  90  50
HYS  84  63  73  61 /  10  60  70  30
P28  85  65  69  62 /  20  90  90  50


FLASH FLOOD WATCH from this evening through Wednesday afternoon
FOR KSZ043-044-061>064-074>081-084>090.



SHORT TERM...Umscheid
LONG TERM...Russell
AVIATION...Umscheid is the U.S. government's official web portal to all federal, state and local government web resources and services.