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The Next Storm/Next Snow Forecast Discussion from the Cherrywood Observatory – September 11, 2017

This content was originally published by the Longmont Observer and is licensed under a Creative Commons license.

Forecast Discussion:

The smoke has cleared (so no HRRR maps today) and a bit more moisture has flowed into the West. Figure 1 shows there is some water vapor from all sorts of directions. It does appear that Hurricane Irma has some moisture in it as well. Figure 2 is the upper air map from Sunday PM showing those same moisture channels.  The ridge is sitting on Colorado keeping us above normal as far as daytime high temperatures go. Some chances of afternoon showers will continue as they fire in the foothills and a few wander east to *maybe* get to us.

Figure 1: Sunday PM Water Vapor satellite image with moisture flow in green.

Figure 2: Sunday PM 500mb upper air map with moisture flow in green.

The Longer Range Forecast:

We stay above normal and pretty dry until Wed/Thur when a cool front may come down and knock us down to the lower 80's and bring just a bit of a better chance of rain.  There isn't much to show graphically yet at this point.

Figure 3 shows the current forecast for Irma and how it will be heading to the Mississippi River Valley and the Tennessee/Kentucky/ Indiana and Ohio area. Figure 4 shows the arrival time, over the next day, of tropical storm forced winds up into the SE US. Figure 5 shows 2+ inches of rain falling between now and Thursday AM for much of Alabama, Georgia, South Carolina, and parts of Tennessee and North Carolina.  And, of course, 6+ inches of rain over a lot of Florida.

And lest we forget Hurricane Jose, it is projected to do loop-d-loops out in the ocean with the last position next Friday heading a bit back toward the U.S.  We'll keep one eye on it all week.

Figure 3: NOAA/NWS Hurricane Irma forecast from Sunday PM.

Figure 4: Arrival time of tropical storm forced winds (or greater) for Irma.

Figure 5: Total accumulated precipitation Sunday PM to Thursday Morning.

Figure 6: Forecast track of Hurricane Jose from the NWS/NHC from Weatherunderground.

Current Weather

Cloudy

Cloudy

53°F

UV Index
0 Low
Pressure
29.87 Rising
Visibility
8 miles
Dewpoint
35 °F
Humidity
52%
Wind
NNW 3.9 mph
Gust
9.9 mph
Wind Chill
53 °F

Hourly Forecast

Today
11 PM
49°F
Mostly cloudy
Tomorrow
12 AM
46°F
Cloudy
Tomorrow
1 AM
44°F
Cloudy
Tomorrow
2 AM
42°F
Mostly cloudy
Tomorrow
3 AM
40°F
Mostly cloudy
Tomorrow
4 AM
38°F
Mostly cloudy
Tomorrow
5 AM
37°F
Mostly cloudy
Tomorrow
6 AM
35°F
Mostly cloudy
Tomorrow
7 AM
37°F
Mostly cloudy
Tomorrow
8 AM
41°F
Mostly sunny
Tomorrow
9 AM
46°F
Partly sunny
Tomorrow
10 AM
50°F
Partly sunny

7 Day Forecast

Mostly cloudy

Wednesday

68 °F

A morning shower in spots; otherwise, clouds and breaks of sun


Thunderstorms

Wednesday Night

35 °F

A thunderstorm in parts of the area this evening; otherwise, mostly cloudy


Intermittent clouds

Thursday

63 °F

A blend of sun and clouds


Mostly cloudy

Thursday Night

39 °F

Mostly cloudy


Partly sunny

Friday

64 °F

Some sun; breezy in the afternoon


Partly cloudy

Friday Night

36 °F

Partly cloudy


Partly sunny

Saturday

66 °F

Partial sunshine


Mostly clear

Saturday Night

41 °F

Clear to partly cloudy


Mostly cloudy

Sunday

78 °F

Rather cloudy and warmer; breezy in the afternoon


Mostly cloudy

Sunday Night

43 °F

Rather cloudy


Sunrise and Sunset

Sunrise
5:59 AM
Sunset
7:56 PM

Based on AccuWeather data