Flagstaff’s dewpoints are much above average historic levels. This is driving our intense rainfall amounts. The Flagstaff airport has received 4.165 inches of rain. I have gotten 2.74 inches at my house. 2008, the first July with my station operating, I measured over 4 inches of rain. Bellemont has received 3.13 inches. These variances are typical of the monsoon season. One place gets rain, the next place gets nothing.
But, the dewpoints are quite high. Here is a graph for July.
Flagstaff Dewpoint Temperature - July 2010
After a slow start, the moisture is firmly in place. The National Weather Service actually has “Heavy Rain” in the forecast for the next few days. We can expect more of the same for the next few days.
Sadly, the folks in the Timberline area are still realizing the severe damage from the campfire-caused Schultz Fire. With this weeks heavy monsoon action, flash flooding has ruined homes and neighborhoods and taken the life on one young girl. Keep those folks in your thoughts and prayers.
The National Weather Service has done a great job warning about this danger well in advance of the recent onset of the monsoonal thunderstorms. Here are several important links:
July 20 Flood
Schultz Burn Area Hydrologic Outlook
NWS Flash Flooding
Moisture levels are going to continue to remain high for the rest of this week. Localized flash flooding can happen in many areas. Also, keep in mind that the storm doesn’t have to be overhead to affect flooding in your area. It can take place miles away, but the drainage pathways, narrow canyons and washes, can lead the water to cause massive flooding at your location.
Yesterday, and again today, general cloudiness is a sign of moisture being present. But, if the clouds don’t “burn-off” it can inhibit the formation of thunderstorms. Thunderstorms provide the lift to produce the cooling and condensing of the water vapor. The diffuse lighting and cloud reflect prevent the formation of storms.
Days like today can limit precipitation, or see formation of thunderstorms later in the day.
Did not really see the big storm coming yesterday. I thought things would hold off until today, Saturday. This should be the weather pattern for the weekend. Dewpoints have remained high. There is plenty of precipitable water. Watch-out for flash flooding.
Check this out. A record high and a record low within a few hundred miles of each other? Must be monsoon season.
Record Report
000
SXUS75 KFGZ 170155
RERFGZ
RECORD EVENT REPORT
NATIONAL WEATHER SERVICE FLAGSTAFF, AZ
600 PM MST FRI JUL 16 2010
...RECORD HIGH LOW TEMPERATURES FOR NORTHERN ARIZONA ON JUL 16 2010...
CITY (PERIOD OF RECORD) NEW HIGH LOW PREVIOUS RECORD/YEAR
HEBER RS (1951 - 2010) 66 65 IN 1963
PRESCOTT (1898 - 2010) 71 70 IN 1970
...RECORD HIGH TEMPERATURES FOR NORTHERN ARIZONA ON JUL 16 2010...
CITY (PERIOD OF RECORD) NEW HIGH PREVIOUS RECORD/YEAR
PAGE (1958 - 2010) 106 104 IN 2006
...RECORD LOW TEMPERATURES FOR NORTHERN ARIZONA ON JUL 16 2010...
CITY (PERIOD OF RECORD) NEW LOW PREVIOUS RECORD/YEAR
PETRIFIED FOREST (1931 - 2010) 50 52 IN 1935
THESE RECORDS ARE PRELIMINARY PENDING OFFICIAL REPORTS.
The dark red areas on this map are excessive heat warning areas.
Excess Heat Warnings - July 15, 2010
They just happen to correspond to the desired location of a deep thermal low that would assist the moisture flow to the Flagstaff area. As many people have said, it really has to get hot for the monsoon to really kick in. It has been getting progressively warmer the last few days. At the same time, dewpoints have stayed mostly in the 40′s. The next few days will be mostly dry with plenty of big puffy clouds, but things should change by the weekend.
Thermal low pressure and the flow of monsoonal moisture
My weather station logged 0.29 inches on Sunday, as a couple thunderstorm waves moved over Flagstaff. Not every place logged as much.
Flagstaff Dewpoint - SUmmer 2010
Monday will maintain higher dewpoints and good chances for thunderstorms. But, as we go into the week, we will see dryer air move back into the area. Of course, this means lower chances for thunderstorms. They should still be possible.
It’s interesting to note that Los Angeles is still in the “June Gloom” mode. This is fairly late in the season for cooler temperatures and gloomy conditions. They set a record for a low, daily maximum temperatures. I am wondering what the meaning of this and high heat on the East Coast and in Central Europe are to our summer monsoon outlook.
This picture represents what happens when we get high pressure building in the right place. Things should build for the next few days, with the weekend have a strong chance for scattered thunderstorms.
Monsoon Pattern to Return
Well, the 4th of July came and went without the slightest hint of a thunderstorm. This is notable. Seems like July 4th’s bring precipitation to the Northland.This pattern should shift this week. For the next couple of days, high pressure to the southwest of us, which has crept in from the west, will dominate and continue to bring us southwest winds. The flow will shift later in the week as low pressure builds to the southwest of us. This sets up the typical monsoonal flow. By next weekend, the moisture should return, with thunderstorms building.
The Arizona Daily Sun has a front page article about our notable weather last year. As a reminder, the dry monsoon season last summer was due to El Nino. El Nino repositioned the high pressure over us and prevented the monsonal moisture flow.Wildly clear skies resulted in our above average temperatures and no cooling from daily cloud development. El Nino was also responsible for our major snow falls. But, El Nino you typically bring a warmer pattern for the winter. This was clearly not the case.
As a result of the Schultz fire, there is an enhanced risk of flash flooding in the burned areas and to the east of these areas. The National Weather Service is seeking additional spotters in the area.
Rainfall Spotters Needed for Schultz Fire Area
From the National Weather Service Flagstaff:
Hydrologic Outlook
HYDROLOGIC OUTLOOK
AZZ015-092300-
HYDROLOGIC OUTLOOK
NATIONAL WEATHER SERVICE FLAGSTAFF AZ
230 PM MST FRI JUL 2 2010
...SCHULTZ FIRE BURN AREA INCREASES RISK OF FLASH FLOODING...
IN THE AFTERMATH OF THE SCHULTZ FIRE...THE BURNED AREA AND THE AREA
EXTENDING EASTWARD TO HIGHWAY 89 IS MORE SUSCEPTIBLE TO FLASH
FLOODING AND DEBRIS FLOWS. THIS INCLUDES THE HUTCHINSON ACRES AND
TIMBERLINE NEIGHBORHOODS. RISES IN WATER LEVELS DURING SUCH EVENTS
MAY OCCUR MORE RAPIDLY AND MAY BE SIGNIFICANTLY GREATER THAN THOSE
PRODUCED PRIOR TO THE FIRE. THE GREATEST POTENTIAL FOR FLASH FLOODS
AND DEBRIS FLOWS WILL LIKELY BE IN AND NEAR THE MINOR DRAINAGES
EXTENDING EASTWARD FROM THE BURN.
A SHORT PERIOD OF MODERATE RAINFALL ON A BURNED WATERSHED CAN LEAD
TO FLASH FLOODS OR DEBRIS FLOWS. RAINFALL THAT IS NORMALLY ABSORBED
CAN RUN OFF EXTREMELY QUICKLY AFTER SOILS AND VEGETATION HAVE BEEN
CHARRED. CONSEQUENTLY...RUNOFF WILL BE GREATER AND MORE RAPID THAN
PRIOR TO THE FIRE. FLOOD WATERS CAN PICK UP LARGE AMOUNTS OF
ASH...SAND...SILT...ROCKS...AND REMNANTS OF VEGETATION. THE FORCE OF
RUSHING WATER AND DEBRIS CAN DAMAGE OR DESTROY
CULVERTS...BRIDGES...ROADWAYS...AND IN SOME CASES
BUILDINGS...POTENTIALLY CAUSING INJURY OR DEATH.
RESIDENTS IN FLOOD PRONE AREAS BETWEEN THE BURN AREA AND HIGHWAY 89
SHOULD HAVE AN EMERGENCY KIT AND A PLAN TO EVACUATE. IF ROADS ARE
BLOCKED OR IT IS UNSAFE TO EVACUATE /DUE TO FLASH FLOODING...DEBRIS
FLOWS...HEAVY RAIN...OR POOR VISIBILITY/ IT IS BEST TO SHELTER IN
PLACE IN A STURDY STRUCTURE. CALL 911 IF YOU ARE CAUGHT IN A FLASH
FLOOD OR DEBRIS FLOW. IF YOU ARE IN A VEHICLE...DO NOT DRIVE INTO
FLOOD WATERS OR DEBRIS FLOWS.
WHEN THE NATIONAL WEATHER SERVICE ISSUES A FLASH FLOOD WATCH FOR THE
SCHULTZ BURN AREA...IT MEANS THAT FLASH FLOODING IS POSSIBLE IN YOUR
AREA. YOU SHOULD START PLANNING FOR POSSIBLE EVACUATION IF YOUR AREA
IS PRONE TO FLASH FLOODING.
WHEN THE NATIONAL WEATHER SERVICE ISSUES A FLASH FLOOD WARNING FOR
THE SCHULTZ BURN AREA...IT MEANS THAT FLASH FLOODING IS ALREADY
OCCURRING OR WILL OCCUR VERY SOON. DO NOT DELAY TAKING PROTECTIVE
MEASURES EVEN IF RAINFALL IS LIGHT AT YOUR LOCATION. ONCE RAINFALL
BECOMES HEAVY...EVACUATION ROUTES MAY BECOME IMPASSIBLE.
IF YOU HAVE ANY QUESTIONS RELATED TO THE CONTENT OF THIS
PRODUCT...PLEASE CONTACT
GEORGE HOWARD
WARNING COORDINATION METEOROLOGIST
NATIONAL WEATHER SERVICE - FLAGSTAFF
928-556-9161 X223
GEORGE.HOWARD@NOAA.GOV
$$
TC/GFH
VISIT WEATHER.GOV/FLAGSTAFF FOR OFFICIAL WARNINGS AND FORECASTS.
But, it looks like we will get beautiful weather for the 4th of July weekend.
Alex will meander across Northern Mexico and slowly devolve. As it does, it will break up the monsoon pattern and draw moisture back to the south. Another sign of the break up of the pattern will be a return of dry southwest winds to the area.
This isn’t unusual. Hurricanes effect the weather for at least 1000 miles. Rita and Katrina dried out Northern Arizona as they went ashore near New Orleans in 2005. I think the moisture will linger to the south and make a quick return next week.
