Latest ZFP from WFO RIW

		
National Weather Service Local Forecast for Star Valley Ranch
Updated: 18 Mar 16:30 pm MDT

This Afternoon... Sunny, with a high near 44. Light west
northwest wind. 

Tonight... Patchy fog after 4am.  Otherwise, mostly clear, with
a low around 17. Light and variable wind becoming east around 6 mph in
the evening. 

Tuesday... Patchy fog before 9am.  Otherwise, sunny, with a
high near 43. East wind 3 to 5 mph. 

Tuesday Night... Mostly clear, with a low around 19. East wind
3 to 7 mph. 

Wednesday... Sunny, with a high near 50. East southeast wind 6
to 8 mph. 

Wednesday Night... Mostly clear, with a low around 21. East
wind around 6 mph. 

Thursday... Partly sunny, with a high near 51. East wind around
5 mph. 

Thursday Night... Mostly cloudy, with a low around 26.

Friday... Mostly cloudy, with a high near 47.

Friday Night... Mostly cloudy, with a low around 29.

Saturday... A chance of rain and snow.  Mostly cloudy, with a
high near 44.

Saturday Night... A chance of rain and snow.  Mostly cloudy,
with a low around 28.

Sunday... A chance of snow.  Mostly cloudy, with a high near
42.

		

Latest AFD from WFO RIW

		National Weather Service Riverton WY
219 PM MDT Mon Mar 18 2019

.SHORT TERM...This evening through Tuesday night
Issued at 214 PM MDT Mon Mar 18 2019

Another weak upper level disturbance will move across Wyoming
tonight. Once again it will increase cloud cover and maybe a slight
increase in wind speeds in the east. Cloudiness in the southwest
will slow radiation a bit overnight but there should be enough
cooling to bring another round of patchy fog to the Green River
Basin as well as the western valleys Tuesday morning. Skies will
begin clearing from the north Tuesday morning and progress southward
through the day. The Bighorn Basin will receive the longest period
of heating and thus should be our warmest area tomorrow. We dropped
low temps a bit across the area Tuesday night with clear skies
allowing greater radiational cooling.

.LONG TERM...Wednesday through Monday
Issued at 214 PM MDT Mon Mar 18 2019

On Wednesday, we will see a jump in the high temperatures as the
Alberta Clipper exits tot the southeast and the narrow ridge of high
pressure builds in from the west. Highs will be well into the 50s in
the Big Horn Basin Wednesday and the 40s most everywhere else with
stable air in place minimizing the potential for reaching the max
potential high temps if otherwise totally mixed, along with snow
cover cooling areas that would otherwise mix like Casper. With the
sfc still high over Southwest Wyoming Wednesday morning remaining in
place, would expect to see a repeat of patchy fog along portions of
the Interstate 80 corridor through Sweetwater County, extending up
into the adjacent Upper Green River basin as well.

Then all eyes turn south toward the southern stream energy. Last
night’s 06Z model run differ from yesterdays 12Z run which indicated
a col region separating the ridge building in. Also, earlier runs
had the other solns siding with the GFS punching the southern stream
low  through the “weakness” in the ridge bringing the vertically
stacked weak low right across Central Wyoming. Lat nights 06Z run
wanted to keep the track of the low to the south over Utah and Co
once again with the ridge in tact. The model waffling continues with
this mornings 12Z run showing the GFS soln of tracking the low
northeast across Southeast Wyoming, the Euro actually taking it
northeast into Montana, and the Canadian taking the main low across
southeast Colorado,  with a second circulation across Southeast
Wyoming. With all this uncertainty and lack of , along
with the GFS bias of bringing the system in too fast, will keep low
pops across the southwest and south for now for Thursday through
Friday, with low pops extending as far northeast as the Wind River
Mtns. Then on Friday night, the next upstream Pacific shortwave will
move in from the west and will weaken as it encounters the ridge and
combine with the weak southern stream system to keep chc pops over
the far west as well as the Big Horn Mtns Friday night through
Monday. The level of certainty as to how these two weather systems
track and interact is low at this point in time. Any precip that
does fall will likely be snow in the mtns along with rain/a rain
snow mix/wet snow in the lower elevations.

&&

.AVIATION...For the 00Z TAFS through 00Z Tuesday afternoon
Issued at 214 PM MDT Mon Mar 18 2019

VFR conditions will occur at the terminal sites through 18Z
Wednesday. Patchy mid level clouds will track southeast across
Northern and East Central Wyoming through Tuesday morning. Patchy
fog is possible at KBPI and KRKS late tonight and Tuesday morning.

&&

.FIRE WEATHER...
Issued AT 214 PM MDT Mon Mar 18 2019

Mainly dry and settled weather will continue. A weak weather system
will continue to move through o Wyoming tonight. However, it has
little moisture to work with. As a result only light mountain
showers are expected and even these will be few and far between.
Wind should remain light to moderate with relative humidity
remaining above critical levels. Mixing and smoke dispersal will be
generally fair to poor. Mainly dry weather should continue for most
locations through Wednesday. Patchy fog is expected during the
morning hours in Southwest Wyoming Tuesday and Wednesday.

&&

.RIW WATCHES/WARNINGS/ADVISORIES...
NONE.
&&
		

Latest GFS MOS for JAC

		KJAC   GFS MOS GUIDANCE    3/18/2019  1800 UTC
DT /MAR  19                  /MAR  20                /MAR  21
HR   00 03 06 09 12 15 18 21 00 03 06 09 12 15 18 21 00 03 06 12 18
N/X              16          45          12          46       18
TMP  34 30 26 23 19 20 33 42 43 31 22 18 14 17 33 43 45 35 28 20 39
DPT  20 20 19 17 16 16 18 16 14 14 14 13 11 11 14 15 14 16 17 16 17
CLD  CL CL CL CL CL CL CL CL CL CL CL CL CL CL CL CL CL CL CL CL CL
WDR  32 01 01 01 01 36 01 33 32 02 01 02 01 01 00 36 35 02 01 01 35
WSP  04 05 06 07 07 04 01 03 03 06 07 06 05 01 00 03 07 07 10 07 02
P06         4     0     0     0     0     0     0     0     1  0  1
P12               4           0           0           1        1
Q06         0     0     0     0     0     0     0     0     0  0  0
Q12               0           0           0           0        0
T06      0/ 0  0/ 0  0/ 0  0/ 3  0/ 0  0/ 0  0/ 0  0/ 0  0/ 0  0/ 0
T12                  0/ 0        0/ 3        0/ 0        0/ 0  0/ 0
POZ   1  1  1  1  0  1  1  0  0  1  1  0  0  2  1  0  0  1  1  0  1
POS  97100 99 96100 94 99 97 91 86 93 91 99 83 92 70 66 77 90 98 79
TYP   S  S  S  S  S  S  S  S  S  S  S  S  S  S  S  S  S  S  S  S  S
SNW                                       0                    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




711
FOUS25 KWNO 181800

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

KJAC   GFSX MOS GUIDANCE   3/18/2019  1200 UTC
FHR  24  36| 48  60| 72  84| 96 108|120 132|144 156|168 180|192
     TUE 19| WED 20| THU 21| FRI 22| SAT 23| SUN 24| MON 25|TUE CLIMO
N/X  13  46| 11  46| 13  49| 23  47| 26  47| 29  41| 20  47| 23 18 43
TMP  16  43| 13  45| 16  47| 25  45| 27  45| 31  39| 23  45| 25
DPT  14  13| 10  13| 10  17| 23  25| 25  28| 28  24| 20  20| 21
CLD  CL  CL| CL  CL| CL  CL| PC  PC| PC  PC| OV  PC| PC  CL| CL
WND   8   8|  8   7|  7   5|  5   7|  7   7|  9   9|  9   8|  9
P12   5   0|  1   1|  1   2|  6  19| 19  23| 36  33| 23  17| 10999999
P24       5|      1|      3|     23|     31|     47|     27|      999
Q12   0   0|  0   0|  0   0|  0   0|  0   0|  1   1|       |
Q24       0|      0|      0|      0|      0|      1|       |
T12   0   0|  0   1|  1   2|  1   1|  2   2|  2   3|  0   2|  0
T24        |  0    |  1    |  2    |  4    |  3    |  6    |  2
PZP   2   0|  0   1|  0   2|  0   0|  0   0|  0   1|  1   0|  0
PSN  93  95| 88  67| 67  54| 56  53| 59  68| 64  84| 88  85| 82
PRS   5   4|  6  24| 22  23| 23  18| 21  16| 19  15|  9  10| 10
TYP   S   S|  S   S|  S   S|  S   S|  S   S|  S   S|  S   S|  S
SNW       0|      0|      0|      0|      0|      0|       |