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Latest ZFP from WFO RIW
	
National Weather Service Local Forecast for Star Valley Ranch
Updated: 21 Aug 05:47 am MDT

Today... Sunny, with a high near 87. Light and variable wind
becoming west 5 to 8 mph in the afternoon. 

Tonight... Mostly clear, with a low around 50. West wind 5 to 9
mph becoming light and variable. 

Thursday... Mostly sunny through mid morning, then becoming
cloudy, with a high near 81. Light and variable wind becoming west 5
to 10 mph in the afternoon. 

Thursday Night... Mostly clear, with a low around 49. West wind
5 to 8 mph becoming calm  in the evening. 

Friday... Sunny, with a high near 81. Light and variable wind
becoming west 5 to 10 mph in the afternoon. Winds could gust as high
as 21 mph. 

Friday Night... Mostly clear, with a low around 52. West wind 5
to 9 mph becoming calm. 

Saturday... Mostly sunny, with a high near 82. South wind 5 to
10 mph becoming west in the afternoon. Winds could gust as high as 24
mph. 

Saturday Night... Partly cloudy, with a low around 52.

Sunday... Sunny, with a high near 78.

Sunday Night... Clear, with a low around 47.

Monday... Sunny, with a high near 78.

Monday Night... Clear, with a low around 46.

Tuesday... Sunny, with a high near 79.

	

Latest AFD from WFO RIW
	National Weather Service Riverton WY
527 AM MDT Wed Aug 21 2019

.SHORT TERM...Today through Thursday
Issued at 350 AM MDT Wed Aug 21 2019

Today will be similar to yesterday with areas west of the Divide and
the southwest staying warm and dry with RH values in the teens to
possibly single digits. Winds are slightly stronger today but not
high enough to warrant any highlights. East of the Divide will once
again have slightly higher RH values. A shortwave along with
moisture advection will increase precipitation chances in the
afternoon hours, mainly in and near the Absaroka and Bighorn
Mountains. Some of these storms could be strong with gusty winds
being the main threat. Models are conflicting a bit with the
indices. GFS currently seems the most reasonable with areas of CAPE
at 1400 J/kg across the north in the early afternoon, then bringing
in CAPEs of 2000 J/kg later. Dew points look to be in the 45 to 50
degree range at peak heating. NAM has been the most aggressive and
HRRR is somewhere in the middle. We leaned more towards the GFS.

Tonight into Thursday morning an upper level trough will begin to
move into the Pacific Northwest. This trough will bring a cold front
across the area east of the Divide during the day Thursday. This
front will once again kick off afternoon showers and thunderstorms
in the north. Thursday will also see and increasing pressure
gradient and strong gusty winds across southern Wyoming from
Southern Lincoln County to the Green Mountains. This combined with
relative humidities in the low teens to single digits has resulted
in the issuance of a Fire Weather Watch for Thursday afternoon and
evening.

.LONG TERM...Thursday night through Wednesday
Issued at 350 AM MDT Wed Aug 21 2019

By Friday, the midlevel trough will be sweeping across northern
WY. Latest model runs have been a bit deeper and slower with the
trough, which may linger it long enough to spark a few showers for
the northern mountain ranges. The trough will sweep northeast
Friday evening, leaving zonal flow into the weekend. Dry air will
remain in place into early next week, so rain chances remain
slight. Longer range models continue to draw the western edge of
the ridge up the west coast, with troughing diving into the
northern US. Models are differing on how deep this trough dives,
so confidence is still kinda low on any airmass changes into the
middle of next week so far.

&&

.AVIATION...For the 12Z TAFS through 12Z Thursday
Issued at 0527 AM MDT Wed Aug 21 2019

Isolated showers will remain possible through the predawn hours
across Johnson County. A moist, easterly surface flow could result
in low clouds (MVFR) developing/advecting westward into Johnson and
Natrona counties between 10Z and 13Z. If low clouds indeed form and
become widespread enough, they could last through midday (~17Z).
This would impact the KCPR terminal. Due to the widespread rainfall
east of Natrona County this evening will introduce MVFR ceilings for
Wednesday morning.

The focus shifts to robust afternoon and evening thunderstorms
developing along and east of the Divide. Looks like widely scattered
thunderstorms will develop over/near the Absaroka/Wind River
mountains in the early afternoon and shift eastward through the
afternoon and evening. The best chances for thunderstorms will be
terminals near the mountains (KCOD and KLND), but will have VCTS at
all terminals. Brief MVFR/IFR conditions are possible with any
convection.
&&

.FIRE WEATHER...
Issued AT 350 AM MDT Wed Aug 21 2019

...Multiple Fire Weather Watches for Thursday afternoon across
southwest Wyoming...

Conditions today will be similar to Tuesday with isolated to
scattered thunderstorms returning mainly over the mountains during
the afternoon. Some storms may be strong with gusty winds being the
main threat. West of the Divide will remain hot and dry this
afternoon, with poor RH recovery tonight. Winds will be stronger
today than Tuesday but not to the point of causing fire concerns.
Thursday will see a cold front push across Wyoming east of the
Divide. This will bring more afternoon showers and thunderstorms
east of the Divide, and increase winds in the still very dry areas
west of the Divide. A Fire Weather Watch has been issued for many
fire zones along and west of the Divide for Thursday afternoon and
evening.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
Fire Weather Watch from Thursday afternoon through Thursday
evening for WYZ277>279-288-289.

&&
	

Latest GFS MOS for JAC
	KJAC   GFS MOS GUIDANCE    8/21/2019  0600 UTC
DT /AUG  21      /AUG  22                /AUG  23             /
HR   12 15 18 21 00 03 06 09 12 15 18 21 00 03 06 09 12 15 18 00 06
X/N              86          43          81          40       78
TMP  45 55 73 84 82 68 55 48 44 54 72 79 77 63 52 46 42 51 67 76 52
DPT  37 39 41 32 30 34 35 36 36 40 41 36 34 32 32 34 35 37 38 31 33
CLD  CL CL CL SC SC FW CL SC BK BK OV OV BK CL CL CL CL CL CL CL CL
WDR  01 01 20 20 25 35 36 36 36 23 20 22 22 22 36 36 01 19 20 25 03
WSP  05 02 04 07 08 10 08 06 04 02 10 16 15 09 05 04 03 03 05 11 04
P06         0     6     2     0     0     0     0     0     1  1  2
P12               6           2           1           0        1
Q06         0     0     0     0     0     0     0     0     0  0  0
Q12               0           0           0           0        0
T06      5/ 0 20/ 0  7/ 0  4/ 0  4/ 0 31/ 3 10/ 1  1/ 0  1/ 0  2/ 0
T12                 21/ 0        9/ 2       31/ 3        2/ 0  9/ 0
CIG   8  8  8  8  8  8  8  8  8  8  8  8  8  8  8  8  8  8  8  8  8
VIS   7  7  7  7  7  7  7  7  7  7  7  7  7  7  7  7  7  7  7  7  7
OBV   N  N  N  N  N  N  N  N  N  N  N  N  N  N  N  N  N  N  N  N  N



791
FOUS26 KWNO 210600

-----------------

KJAC   GFSX MOS GUIDANCE   8/21/2019  0000 UTC
FHR  24| 36  48| 60  72| 84  96|108 120|132 144|156 168|180 192
WED  21| THU 22| FRI 23| SAT 24| SUN 25| MON 26| TUE 27| WED 28 CLIMO
X/N  86| 43  80| 41  79| 40  81| 48  84| 47  83| 37  75| 36  74 40 76
TMP  83| 45  76| 43  76| 42  80| 51  81| 48  81| 38  72| 38  72
DPT  31| 35  37| 34  28| 32  32| 35  28| 35  26| 26  29| 30  28
CLD  CL| PC  PC| CL  CL| CL  CL| CL  CL| CL  CL| CL  CL| CL  CL
WND   7| 14  17| 15  10| 10  17| 19  24| 23  21| 17  13| 14   8
P12   5|  4   1|  1   1|  3   4|  5   6|  7   5|  7   8| 11  11999999
P24    |      4|      1|      4|      6|      7|     10|     16   999
Q12   0|  0   0|  0   0|  0   0|  0   0|  0   0|  0    |
Q24    |      0|      0|      0|      0|      0|       |
T12  20|  9  29|  9   6|  4   9|  8   8|  6   9|  7  12| 10  14
T24    | 20    | 29    |  6    |  9    | 11    | 10    | 18

	
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