Latest ZFP from WFO RIW

		
National Weather Service Local Forecast for Star Valley Ranch
Updated: 20 Jan 00:31 am MST

Overnight... Snow likely, mainly before 3am.  Cloudy, with a
low around 28. South wind around 8 mph.  Chance of precipitation is
60%. Total nighttime snow accumulation of 1 to 3 inches possible. 

Sunday... A 50 percent chance of snow.  Cloudy, with a high
near 37. South southwest wind 7 to 9 mph.  New snow accumulation of
less than a half inch possible. 

Sunday Night... Snow.  Low around 28. South wind 5 to 8 mph. 
Chance of precipitation is 80%. New snow accumulation of 1 to 3 inches
possible. 

M.L.King Day... Snow, mainly before 11am.  High near 30. South
southwest wind 6 to 11 mph becoming north northwest in the afternoon. 
Chance of precipitation is 80%. New snow accumulation of 1 to 3 inches
possible. 

Monday Night... A 30 percent chance of snow before 11pm. 
Mostly cloudy, with a low around 3. North northwest wind 5 to 9 mph
becoming light north. 

Tuesday... Mostly sunny, with a high near 18. Calm wind
becoming west around 6 mph in the afternoon. 

Tuesday Night... A 30 percent chance of snow, mainly after
11pm.  Mostly cloudy, with a low around 9. West southwest wind around
5 mph. 

Wednesday... Snow showers likely.  Cloudy, with a high near 24.
Chance of precipitation is 60%.

Wednesday Night... Snow showers likely, mainly before 11pm. 
Cloudy, with a low around 16. Chance of precipitation is 60%.

Thursday... A 20 percent chance of snow showers.  Mostly
cloudy, with a high near 27.

Thursday Night... Mostly cloudy, with a low around 14.

Friday... Mostly cloudy, with a high near 26.

Friday Night... Mostly cloudy, with a low around 11.

Saturday... Mostly sunny, with a high near 27.

		

Latest AFD from WFO RIW

		farther north will see less upslope enhancement. Riverton could
see 3 inches of snowfall and Shoshoni in the Owl Creek snow shadow
could see 1 to 2 inches as sfc nne winds increase.. These, of
course, are all preliminary amounts. The Big Horn mtns will get
their share but not as much as the Winds or Casper Mtn. The least
amount of snow will likely occur in the Big Horn Basin. We will be
issuing a winter storm watch in this afternoons package to
address this.

Snowfall will diminish after 06Z Tuesday. Tuesday will be dry.
Temperatures will cool during and behind this weather system.

.LONG TERM...(Tuesday night through Saturday)

A strong, relatively moist northwest flow is expected through the
long term. A couple clipper systems will push southeast across
the region enhancing snow chances at times. Currently, it appears
the first one would impact the area Wednesday into Wednesday
night, and another one possibly on Friday. The former system seems
to impact much of the forecast area while the one on Friday
appears to mainly impact areas along and east of the Divide. Due
to the relatively moist northwest flow, some snow showers could
continue across the northwest/northern mountains in between
clipper systems.

Temperatures look to be slightly below average for much of the
extended, but nothing brutal with the coldest day in the extended
looks to be on Tuesday.

&&

.AVIATION...(For the 06Z TAFS through 06Z Monday)

West of the Continental Divide (KJAC, KRKS, KPNA, KBPI)

Snow will occur in northwest WY, mainly north of an Afton to
Pinedale line through 18Z, then lingering light snow will occur in
the northwest mountains through 00Z Mon. Expect MVFR to IFR
conditions with mountains frequently obscured. After 00Z Mon, snow
will begin to increase in NW WY once again. In southwest WY through
18z, areas of MVFR ceilings will occur, then VFR conditions will
prevail through 06Z Mon.

East of the Continental Divide (KCPR, KCOD, KRIW, KWRL, KLND)

Over northern WY through 18Z, scattered light snow will occur along
with MVFR to IFR conditions. KCOD may see a brief period of snow
from 12Z to 18Z but for now will keep VCSH in the terminal forecast.
Johnson county will see the best coverage of snow from 09Z to 18Z.
After 18Z, VFR conditions will prevail in northern WY.

In the central area, from KLND to KCPR, VFR conditions will prevail
through the period. A gusty wind will continue at KCPR until 12Z,
then less wind through 18Z, then the gusty wind returning around
19Z.

&&

.FIRE WEATHER...

Another weather system will approach the west today and bring
additional snow through Sunday, with the steadiest tonight. Areas
East of the Divide should remain mainly dry through the day today,
tonight and Sunday. Breezy to windy conditions are likely in the
lee of the Absarokas and from the Red Desert through Natrona
County through sunday, mainly during the daylight hours.
Significant snow is expected on both sides of the Divide Sunday
night through Monday night. Mixing and smoke dispersal will be
generally fair to poor.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
Winter Storm Watch from late Sunday night through late Monday
night for WYZ028>030.

Winter Storm Watch from Monday morning through late Monday night
for WYZ007-015-017>020-022.

Winter Weather Advisory until 5 AM MST Sunday for WYZ012-013.

Winter Storm Watch from Sunday afternoon through Monday
afternoon for WYZ001-002-012-013-023-024.

Winter Storm Watch from late Sunday night through Monday evening
for WYZ003>006-008>011.

Winter Storm Watch from Sunday evening through late Monday night
for WYZ027.

&&
		

Latest GFS MOS for JAC

		KJAC   GFS MOS GUIDANCE    1/20/2019  0000 UTC
DT /JAN  20            /JAN  21                /JAN  22          /
HR   06 09 12 15 18 21 00 03 06 09 12 15 18 21 00 03 06 09 12 18 00
X/N                    39          27          30           2    19
TMP  31 33 34 33 35 37 35 33 32 32 31 27 28 27 26 23 17 12  6  9 17
DPT  28 29 31 30 29 28 28 28 28 29 29 27 24 21 17 13  7  3 -1  2  6
CLD  OV OV OV OV OV BK OV OV OV OV OV OV OV OV OV SC SC SC FW CL OV
WDR  20 20 20 19 19 19 18 19 19 19 22 35 34 35 35 36 01 36 01 18 20
WSP  10 13 10 08 10 13 16 13 09 05 09 08 13 20 18 14 13 10 06 03 07
P06        72    50    18    80    86    79    50    10     4  5  5
P12                    51          89          84          10     6
Q06         1     1     0     2     2     2     1     0     0  0  0
Q12                     1           3           2           0     0
T06      0/ 0  0/ 0  0/ 0  0/ 0  0/ 0  0/ 0  1/ 0  0/ 0  0/ 0  0/ 0
T12            0/ 2        0/ 0        0/ 1        1/ 0     0/ 1
POZ   3  2  2  1  1  1  0  1  1  1  0  0  0  0  0  0  0  0  0  0  0
POS  97 94 98 97 96 91 96 97 94 95 95100100 99100100 99100100100100
TYP   S  S  S  S  S  S  S  S  S  S  S  S  S  S  S  S  S  S  S  S  S
SNW                                 6                       1
CIG   4  4  4  3  5  8  6  5  3  4  3  3  4  6  7  8  8  8  8  8  6
VIS   4  3  2  1  5  7  5  3  2  2  2  1  2  5  7  7  7  7  7  7  7
OBV  BR BR BR BR BR  N HZ BR BR BR BR FG BR  N  N  N  N  N  N  N  N




233
FOUS23 KWNO 200000

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

KJAC   GFSX MOS GUIDANCE   1/20/2019  0000 UTC
FHR  24| 36  48| 60  72| 84  96|108 120|132 144|156 168|180 192
SUN  20| MON 21| TUE 22| WED 23| THU 24| FRI 25| SAT 26| SUN 27 CLIMO
X/N  39| 27  30|  2  19| 12  25| 19  32| 13  28|  8  27|  1  29  6 29
TMP  35| 31  26|  6  17| 16  24| 23  29| 16  27| 13  25|  5  26
DPT  28| 29  17| -1   6| 10  19| 19  23| 13  18|  7  14|  2  12
CLD  OV| OV  OV| OV  PC| OV  OV| OV  OV| OV  OV| OV  CL| PC  CL
WND  16| 16  20| 18   7| 11  11| 14  10| 12  10| 10  10|  7   7
P12  51| 89  84| 10   6| 27  61| 66  32| 25  16| 18  15| 11  13999999
P24    |     92|     17|     68|     73|     30|     25|     20   999
Q12   1|  3   2|  0   0|  0   2|  2   1|  0   0|  0    |
Q24    |      4|      0|      1|      2|      0|       |
T12   0|  0   1|  0   0|  0   0|  0   0|  0   0|  0   0|  0   0
T24    |  0    |  1    |  0    |  0    |  0    |  0    |  0
PZP   3|  1   1|  0   1|  1   1|  2   1|  1   1|  1   1|  1   1
PSN  85| 88  86| 97  96| 95  94| 91  94| 93  93| 93  96| 93  95
PRS  12| 10  13|  3   3|  4   5|  8   5|  6   6|  6   4|  6   4
TYP   S|  S   S|  S   S|  S   S|  S   S|  S   S|  S   S|  S   S
SNW    |      8|      0|      4|      2|      0|       |