Guessing the Weather, Part 2

Edit on Sunday afternoon: Well it didn't turn out too bad. Just before the race start Hobby Airport had 55 degrees with a 54 degree dewpoint, fog, and NW wind at 3mph. At 0753 the temperature had warmed to 56 and the dewpoint to 55. At 0853 it had warmed up a little more to 58 degrees with a dewpoint of 56 and the wind increased to NW at 7. The wind went calm by 0953 as the temperature increased to 59 and the dewpoint went to 57. By 1053 it had warmed to 65 with a 62 degree dewpoint. It got really tough by 1153 with the wind turning around to S14 with gusts to 22 and the Gulf air coming in raising the temperature to 73 and the dewpoint to 68. That's some pretty difficult conditions. Did anyone else feel they were hurt by the slippery streets? I swear my feet were sliding back a foot on every toe-off down University.

I thought it was interesting that the NWS put out a mea culpa Sunday afternoon:
"FIRST...THIS MORNING`S FORECAST. OUR FORECASTS HAVE BEEN PRETTY GOOD THE PAST COUPLE OF DAYS. WE IGNORED ALL MODELS THAT WERE CONSISTENTLY TOO WARM AND TOO SLOW ON THE FRONTAL MOVEMENT. YESTERDAY`S BEST MODEL MOVED THE FRONT BACK TO THE NORTH...BUT IT KEPT ON HEADING SOUTH. SO WHEN TODAY`S BEST MODEL MOVED THE FRONT BACK TO THE NORTH...WE LEANED TOWARD OUR ONGOING SUCCESSFUL FORECAST THAT HAD THE BOUNDARY LINGERING NEAR THE COAST. THIS TIME...WE WERE WRONG AND THE FRONT DID MOVE BACK
INLAND. FORECAST UPDATES WERE CREATED AND SENT OUT AS SOON AS WE COULD GET THEM DONE."

Edit on Saturday: There were some changes in the National Weather Service forecast overnight. They now show the front moving in much sooner. Some of the other forecasters show the front moving in sooner, but then stalling. It seems as though we won't be certain over the weather until after we cross the finish line. All of this uncertainty with the weather reminds me a little of this old Joan Benoit Nike commercial

Edit at 1130 on Saturday: Here's the discussion from the NWS: HOW FAR SOUTH THE FRONT WILL GO IN THE NEXT 24 HOURS? THAT REMAINS THE BIG QUESTION THIS MORNING. THE FRONT HAS BEEN MOVING FASTER THAN ANY MODELS HAVE INDICATED...AND THIS HAS RESULTED IN THE ARRIVAL OF THE COLDER TEMPERATURES FASTER THAN ANTICIPATED. SOME OF THE 12Z MODELS ARE INDICATING STEADY FRONTAL PROGRESS TOWARD OUR CENTRAL AND SOUTH CENTRAL ZONES TONIGHT THEN MOVE THE BOUNDARY BACK NORTH DURING THE DAY TOMORROW...THEN FINALLY MOVE IT OFF THE COAST SUNDAY NIGHT AS THE COLDER AIRMASS FINALLY SINKS INTO THE AREA. CURRENT THINKING IS THAT THE FRONT WILL CONTINUE TO SLOWLY PROGRESS TOWARD THE COAST TONIGHT AND SHOULD BE OFF THE COAST BEFORE SUNRISE TOMORROW MORNING. CURRENT FORECAST PACKAGE REFLECTS THIS THINKING SO NO SIGNIFICANT CHANGES ARE ANTICIPATED AT THIS TIME. IF THE FRONT MOVES FASTER THAN ANTICIPATED OVER THE NEXT SEVERAL HOURS...WILL HAVE TO DO SOME UPDATES.


Edit at 2PM on Saturday:
THE FORECAST FOR SOUTHEAST TEXAS NOT GETTING ANY EASIER THIS AFTERNOON DUE TO A WIDE RANGE OF MODEL SOLUTIONS. THE FOLLOWING FORECAST IS BOUND TO CHANGE DUE TO A POSSIBLY SLOWER THAN EXPECTED MOVING COLD FRONT. THE FRONT IS NOW THROUGH BRENHAM (TEMPERATURE DROPPED FROM 70 TO 54 BETWEEN 18Z AND 19Z)...BUT THE BOUNDARY IS STILL JUST TO THE ORTH OF CROCKETT. UNSEASONABLY WARM JANUARY TEMPERATURES PERSIST SOUTH OF THE FRONT WITH LOWER TO MID 70S AREAWIDE (GALVESTON`S 19Z READING OF 71 IS ONLY FOUR DEGREES OFF OF THE RECORD 75 SET BACK IN 1880). SCATTERED LIGHT RAIN SHOWERS CONTINUE TO DEVELOP AHEAD OF THE FRONT. HEAVIER RAIN WITH EMBEDDED THUNDERSTORMS CONTINUE TO TRAIN BEHIND THE FRONT ACROSS THE HILL COUNTRY EXTENDING INTO NORTH TEXAS. THIS AFTERNOON`S FORECAST WILL STICK CLOSE TO WHAT THE PREVIOUS PACKAGE CONTAINED. WILL SHOW THE COLD FRONT MOVING INTO THE CENTRAL COUNTIES AFTER SUNSET TONIGHT AND THEN CROSSING THE COAST BETWEEN MIDNIGHT AND SUNRISE TOMORROW MORNING. TEMPERATURES WILL PLUMMET SOME 10 TO 20 DEGREES AFTER THE FRONT MOVES ON THROUGH. THE AXIS OF HEAVY RAIN TO OUR WEST THIS AFTERNOON MAY SHIFT EASTWARD TONIGHT RESULTING IN A THREAT FOR LOCALLY HEAVY RAINFALL ACROSS OUR NORTHERN COUNTIES. NO FLOOD WATCH WILL BE ISSUED AT THIS TIME...BUT LOCALLY HEAVY RAINFALL WILL BE MENTIONED IN THE ZONES. WILL CARRY HIGH RAIN CHANCES UP NORTH AND LOWER VALUES TOWARD THE COAST. MUCH OF THE AREA WILL BE WET TOMORROW AS TEMPERATURES CONTINUE TO FALL. A SURGE OF COLDER ARCTIC AIR IS STILL ANTICIPATED TO ENTER SOUTHEAST TEXAS TOMORROW NIGHT RESULTING IN A THREAT FOR FROZEN PRECIPITATION. TEMPERATURES ARE EXPECTED TO COOL ENOUGH TO SUPPORT THE FROZEN STUFF UP NORTH (GENERALLY ALONG AND NORTH OF A LINE FROM BRENHAM TO LIVINGSTON) BEGINNING SUNDAY NIGHT AFTER MIDNIGHT...AND THIS WINTER WEATHER THREAT MAY PERSIST INTO WEDNESDAY MORNING. FOR THE CENTRAL AND INLAND COASTAL ZONES (INCLUDING HOUSTON AND SURROUNDING AREAS)...TEMPERATURES ARE EXPECTED TO GET COLD ENOUGH TO SUPPORT FROZEN PRECIPITATION BEGINNING MONDAY EVENING...AND THIS WINTER WEATHER THREAT MAY ALSO PERSIST INTO WEDNESDAY MORNING.


Now that we're just one week away from the Houston Marathon, the biggest remaining factor on marathon performance next Sunday is the weather. Why worry about the weather? After all, everyone else has to run in the same conditions.
I run marathons for the competition against myself. I'm trying to get the fastest time possible and for someone big and heavy, warm and humid weather can kill a fast time. After the very warm marathons of 1998, 1999, and 2000, I promised myself I wouldn't race another marathon with the dewpoint above 60°F. If some of these forecasts hold, I'm thinking about using Houston as a long run and signing up for the New Orleans Mardi Gras Marathon.

Impact Weather says "The front is expected to move through early to midday Sunday with much cooler weather for the beginning of next week."
Edit on Wednesday:
Wind S-SSW 12-17 gust 22 shifting to N 15-20 gust 25 midday
Precip 50% chance of rain.
Temp Morning Low: 65ºF High: 68ºF Late Evening Low...52F
Edit on Thursday: Wind S-SSW 12-17 gust 22 shifting to N 15-20 gust 25 morning; Precip 50% chance of rain; Temp Morning Low:66ºF High:70ºF Late Evening Low...45F
Edit on Friday:Cloudy with a 60% chance of rain and thunderstorms, with the day's warmest temperatures likely be reached in the morning. A strong cold front moves through round mid-day with temperatures falling into the 50s during the afternoon and upper 30s by midnight. Evening Low: 39 Morning High: 72 Wind: SSW 12-17 with gusts to 22 becoming N 15-20 with gusts to 25 around mid-day.
Edit on Saturday: A strong Arctic cold front is scheduled to move across the area Sunday morning and temperatures will fall sharply into the 40s by the late morning hours.



The NWS Forecast doesn't look good:
Saturday Night: A 30 percent chance of showers and thunderstorms. Mostly cloudy, with a low around 60.
Sunday: A 30 percent chance of showers and thunderstorms. Mostly cloudy, with a high near 64.
Edit on Monday: Saturday Night: A 40 percent chance of showers and thunderstorms. Mostly cloudy, with a low around 63.
Sunday: A 40 percent chance of showers and thunderstorms. Mostly cloudy, with a high near 63.
Edit on Tuesday: Saturday Night: A chance of showers. Mostly cloudy, with a low around 63. Chance of precipitation is 40%.
Sunday: A 50 percent chance of showers and thunderstorms. Cloudy, with a high near 68.
Edit on Wednesday: Saturday Night: A 40 percent chance of showers and thunderstorms. Mostly cloudy, with a low around 62.
Sunday: Showers and thunderstorms likely. Cloudy, with a high near 66. Chance of precipitation is 60%.
Edit on Thursday: Saturday Night: A 40 percent chance of showers and thunderstorms. Mostly cloudy, with a low around 66.
Sunday: Showers and thunderstorms likely, mainly after noon. Mostly cloudy, with a high near 71. Chance of precipitation is 60%.
Edit on Friday: Saturday Night: A 30 percent chance of showers and thunderstorms. Mostly cloudy, with a low around 67. South wind around 10 mph.
Sunday: A 50 percent chance of showers and thunderstorms. Mostly cloudy, with a high near 75. South wind 10 to 15 mph becoming west.
Edit on Saturday: BIG CHANGE HERE Tonight: Showers and thunderstorms likely. Cloudy, with a low around 50. South wind 5 to 10 mph becoming north between 15 and 20 mph. Winds could gust as high as 20 mph. Chance of precipitation is 60%.
Sunday: Rain likely. Mostly cloudy, with a high near 54. North wind between 15 and 20 mph, with gusts as high as 20 mph. Chance of precipitation is 60%.


Here's the hourly weather graph. It shows the front coming through just after the race.
Edit on Saturday: BIG CHANGE HERE with the front coming in before midnight tonight! It's showing near-PR conditions right now with the temperature near 50, the dewpoint near 45, a moderate North wind at 10 mph and some light rain for the first five hours of the race. It would be time to brush off the goal pace if that forecast holds.



Here's what the 0-8 day Global Forecast System model shows for Houston:
0-8 Day GFS
Edit on Thursday: We're now in the shorter range GFS model:
0-84 Hour GFS


The model shows a cold front coming through early on Sunday morning. The GFS Meteogram is in Universal Time, so Houston is 6 hours behind the chart. The model now shows Sunday morning in the mid-40s and cooling off to near 40 at noon. Morning wind is North near 16 mph. Don't find yourself alone on Post Oak.
Edit on Monday: The GFS model still shows the cold front arriving early Sunday morning.
Edit on Tuesday: The GFS model now shows the front coming through later. Temperature for race start is predicted in the upper 60s.
Edit on Wednesday: No change in the GFS model.
Edit on Thursday: Race start temperature is now in the lower 60s.
Edit on Friday: Not much change.
Edit on Saturday: The GFS model shows some cooling Saturday night and lower winds, but the front still not coming in until Sunday after the race.

The real question with the forecast is the timing of the cold front. Here's what the
NWS Meteorologists are discussing:
.....NSHORE WINDS/LOW-LEVEL MOISTURE
PROGGED TO RETURN ON/ABOUT LATE WED...PEAKING FRI/SAT. NOT ALL THAT ENAMOURED WITH THE IDEA OF POPS FOR WED AS THE AIRMASS A-CROSS SE TX STILL SEEMS A BIT DRY...BUT THE EXTENDED PROGS ARE INDICATING A RATHER DECENT LOOKING S/WV LATE WED. THE BEST POP
NUMBERS STILL RESERVED FOR THE FRI-SUN PERIOD AS THE NEXT COLD FRONT MOVES THRU. A FEW MORE TIMING DIFFERENCES NOTED WITH THE 12Z RUNS WITH THIS UPCOMING FEATURE - WITH ECMWF CONSPICUOUSLY SLOWER. WILL HAVE TO WAIT AND SEE WHAT LATER RUNS HAVE FOR US.
Edit on Monday: ...WITH THE RETURN FLOW ESTABLISHED...TEMPERATURES WILL BEGIN TO RISE. MOISTURE LEVELS BEGIN TO DEEPEN ON FRIDAY AS INSTABILITIES INCREASE...AND THIS SHOULD BRING THE AREA HIGHER CHANCES OF SHOWERS AND THUNDERSTORMS. THIS INCREASED CHANCE OF STORMS SHOULD PERSIST INTO SUNDAY AS A STRONG COLD FRONT MOVES THROUGH THE AREA. IT LOOKS LIKE SUNDAY`S TEMPERATURES HAVE
THE POTENTIAL TO DROP SIGNIFICANTLY AFTER THE FRONTAL PASSAGE...AND WILL SHOW READINGS FALLING THROUGHOUT THE DAY.
Edit on Tuesday: RAIN CHANCES WILL DEVELOP FRIDAY INTO SATURDAY AS A FRONTAL BOUNDARY OVER THE SOUTHERN PLAINS SLIPS INTO NORTH TX AND THE 500MB TROUGH OVER THE WESTERN U.S. MOVES EASTWARD. WILL HAVE TO WAIT FOR THE SURFACE LOW ACROSS NORTHWEST TX SATURDAY TO LIFT NORTHEAST OF THE TROUGH SUNDAY BEFORE A COLD FRONT MOVES THROUGH SOUTHEAST TX LATE SUNDAY. RAIN CHANCES TO CONTINUE TO INCREASE SATURDAY INTO SUNDAY WITH BEST CHANCE OF SHOWERS AND THUNDERSTORMS DEVELOPING ALONG AND AHEAD OF THE FRONT SUNDAY. A VERY STRONG HIGH PRESSURE RIDGE IS PROGGED BY
THE 00Z GFS TO MOVE INTO THE WESTERN U.S. MONDAY WITH SHALLOW ARCTIC AIR SURGING SOUTHWARD OVER THE CENTRAL U.S. WHILE OVERRUNNING IS PROGGED TO DEVELOP ACROSS SOUTH TX MON MORNING IN THE WAKE OF THE FRONT.
Edit on Wednesday: LOW LEVEL MOISTURE IS EXPECTED TO INCREASE THE NEXT COUPLE OF DAYS AS LOW PRESSURE DEVELOPS ACROSS THE ROCKIES AND A STRONG COLD FRONT MOVES SOUTHWARD ACROSS THE NORTHERN AND CENTRAL PLAINS. MOISTURE IS PROGGED ACROSS THE SOUTHERN PLAINS FRIDAY AS THE BOUNDARY APPROACHES NORTH TX. NOT MUCH OF A FOCUS FOR CONVECTION TO DEVELOP ACROSS THE CWA THURSDAY SO WILL NOT MENTION RAIN CHANCES UNTIL FRIDAY FOR NOW. BEST CHANCE OF RAIN STILL APPEARS SAT NIGHT INTO SUNDAY AS THE COLD FRONT ACROSS NORTHEAST TX SAT AFTERNOON MOVES SOUTHWARD AND THROUGH SOUTHEAST TX SUN AFTERNOON.
Edit on Thursday:CHALLENGING FORECAST FOR THIS WEEKEND INTO NEXT WEEK AS THE ARRIVAL OF A STRONG COLD FRONT SUNDAY WILL USHER COLD ARCTIC AIR INTO SOUTHEAST TX EARLY NEXT WEEK. FIRST...RETURN FLOW TO CONTINUE TO DRAW LOW LEVEL MOISTURE ACROSS THE WESTERN GULF OF MEXICO NORTHWARD THROUGH THE REST OF THE WEEK INTO THE WEEKEND. EXPECT SEA FOG TO DEVELOP ACROSS COASTAL SECTIONS OF SOUTHEAST TX TONIGHT AS WELL AS FRI/SAT NIGHT. NOT MUCH OF A FOCUS FOR CONVECTION TO DEVELOP UNTIL SAT NIGHT AS THE COLD FRONT BARRELS INTO NORTH TX EARLY SATURDAY AND APPROACHES THE NORTHERN PORTIONS OF THE CWA SAT AFTERNOON. HOWEVER...A COUPLE OF UPPER LEVEL IMPULSES WILL MOVE ACROSS THE STATE FRIDAY THROUGH SATURDAY IN THE SOUTHWEST FLOW ALOFT TO WARRANT A MENTION OF SHOWERS FRIDAY AND SHOWERS/THUNDERSTORMS FRI NIGHT INTO SATURDAY BUT WILL LEAN MORE TOWARDS THE DRIER 00Z NAM SOLUTION THAN THE 00Z GFS. AS THE FRONT MOVES INTO SOUTHEAST TX LATE SAT NIGHT/EARLY SUN MORNING...RAIN
CHANCES WILL INCREASE FROM NORTH TO SOUTH AS SHOWERS AND THUNDERSTORMS DEVELOP ALONG AND AHEAD OF THE FRONT. UP UNTIL THIS MORNING...MODELS HAVE BEEN CONSISTENT WITH THE FRONT MOVING THROUGH SOUTHEAST TX SUN AFTERNOON BUT INSTEAD HAVE SLOWED DOWN THE FORWARD SPEED CONSIDERABLY WITH THE GFS NOW BRINGING THE FRONT TO THE COAST BY MIDNIGHT SUNDAY. WITH THE MOMENTUM OF THE ARCTIC AIR...BELIEVE THE GFS IS NOT HANDLING THE SHALLOW AIRMASS VERY WELL SO WILL NOT CHANGE THE PREVIOUS TIMING OF PAST MODEL RUNS.
Edit on Friday:...AIRMASS CONTINUES TO WARM/MOISTEN AS ONSHORE FLOW TRANSPORTS 60-65 DEGREE DEWPOINTS BACK INLAND. MCLDY & WARM CONDITIONS EXPECTED INTO SUNDAY AFTERNOON.
Edit on Saturday: ...IT IS ARRIVING MUCH FASTER THAN MODELS DEPICTED. WITH THE EXCEPTION OF NAM12...MAJORITY OF OTHER 00Z MODELS ARE ALREADY WAY BEHIND THE CURVE. GENERALLY FOLLOWED NAM12 THRU THIS EVENING BY MOVING THE FRONT TOWARD THE INTERSTATE 10 CORRIDOR TOWARD LATE AFTERNOON AND EVENING. MODELS AGAIN ARE TRYING TO HANG THE FRONT UP OVERNIGHT...AND SOME EVEN MOVE IT BACK A LITTLE NORTH ON SUN AS A LLVL WAVE DEVELOPS ALONG THE BOUNDARY. BUT CONSIDERING IT IS A SHALLOW DENSE COLD AIRMASS...WE BELIEVE IT`LL CONTINUE SLOWLY MOVING SOUTHWARD OVERNIGHT. WITH
THAT BEING SAID...WE GENERALLY DISREGARDED ALL THE GUIDANCE AND CONTINUED A SLOWER SOUTHWARD PUSH AND OFF THE COAST LATE TONIGHT. OVERRUNNING MOISTURE AND IMPULSES IN THE SW FLOW ALOFT ARE GENERATING SHRA AND ELEVATED TSRA...WITH THE BULK OF IT OCCURRING BEHIND THE FRONTAL BOUNDARY. ANTICIPATE THIS WILL CONTINUE FOR THE NEXT SEVERAL DAYS AND OUR RAIN CHANCES WILL GRADUALLY BE ON THE WAY UP.
THE COLDEST AIR STILL WILL NOT ARRIVE UNTIL LATE IN THE WEEKEND AND EARLY NEXT WEEK AS THE MAIN SURGE SPILLS DOWN INTO THE CENTRAL U.S. FROM CANADA.


Accuweather has backed up on an earlier cold front arrival. Their low is now 56 with a high of 61 on Sunday.
Edit on Monday: Their low is now 62 with a high of 66 on Sunday.
Edit on Tuesday: No change here.
Edit on Wednesday: Still no change.
Edit on Thursday: Their low is now 64 with a high of 70 on Sunday.
Edit on Friday: Their low is still 64 but the high is 76 for Sunday. ugggg Accuweather hourly
Edit on Saturday: Their holding with steady 65 degrees through the race.


The Weather Channel shows a Saturday night low of 57 with a high of 73 on Sunday and scattered showers.
Edit on Monday: The Weather Channel has moved up the cold front a little. They show a Saturday night low of 56 with a high of 57 on Sunday.
Edit on Tuesday: They now show a Saturday night low of 61 with a high of 64 on Sunday.
Edit on Wednesday: They now show a Saturday night low of 64 with a high of 69 on Sunday.
Edit on Thursday:They now show a Saturday night low of 65 with a high of 72 on Sunday.
Edit on Friday: They now show a morning low at 58 That wouldn't be too bad!
Edit on Saturday: Here's their hourly forecast showing 54 to 61 during the race with winds from the SE at 9 to 12 mph