# Presentation: 815355

## Observed and ForecastSoil Moisture and Rainfall Potential For the Rio Grande Basin

**Gregory E. Wilk  **
**WFO Corpus Christi TX**
**Presented by **
**Mark Lenz**
**Senior Service Hydrologist**
**WFO Austin/San Antonio**

## 2004 RAINFALL SUMMARY

**Above normal rainfall over the Rio Grande Plains and Coastal Bend.**
***2004 Rainfall for Laredo was 27.22 inches (from coop observer)***
***Normal rainfall for Laredo is 21.53 inches***
***Rainfall so far this year (through March 2005) 3.70 inches (normal for March 2.62 inches); April 4.17 inches***
**This was despite the fact that there were no tropical systems affecting the Rio Grande Plains.**

## CURRENT SOIL MOISTURE CONDTIONS

**No drought in Rio Grande Plains**
**Drought in Rio Grande Valley**

## CURRENT SOIL MOISTURE CONDTIONS

**P.D.S.I shows wet conditions in Rio Grande Plains.**
**Mild drought in the Rio Grande Valley**
**P.D.S.I. has a tendency to be slow from going wet to drought**

## CURRENT SOIL MOISTURE CONDTIONS

**K.B.D.I. shows moderate conditions over Rio Grande Plains, but dry conditions over the Rio Grande Valley**
**Values have been increasing over the past few months.**

## Current Conditions – Soil Moisture

**Climate prediction center (CPC) indicates near to slightly below normal soil conditions over the Rio Grande basin.**
**Drier conditions continue to develop due to low rainfall amounts in April.**

## RAINFALL/SOIL MOISTURE OUTLOOK

**Above normal temperatures most likely for the three month period.**
**Near normal rainfall most likely for the three month period.**

## RAINFALL/SOIL MOISTURE OUTLOOK

**Forecast calls for near to slightly moist soil conditions with no drought  (could change if drier than normal conditions occur).**

## 2005 Tropical Season Outlook

**Season ranges from June 1 through November 30 for the Atlantic basin, including the Gulf of Mexico.**
**Dr. Gray’s forecast (from April 1 2005) calls for an above normal season with:**
***13 named storms***
***7 hurricanes***
***3 major hurricanes (category 3 or greater)***
***41% probability for at least one major hurricane landfall over the Gulf Coast, from the Florida Panhandle westward to Brownsville (average from last century is 30%).***

## Enhanced Rain Gauge Network

**Red dots indicate coop observer rain gauge network for Webb County**
**Network has increased since 2002.**
**Goal is to improve river forecasts by increasing rainfall data available.**
**Will increase the number of gauges over the next year over Webb County.**

## AHPS – ADVANCED HYDROLOGIC PREDICTION SERVICE

**Access from WFO CRP home page.**
**Using left mouse button, click on square box to access site data**
**Map legend indicates****:**
***Red: Above Flood Stage***
***Yellow: Above caution stage***
***Green:  Below caution stage***

## AHPS – ADVANCED HYDROLOGIC PREDICTION SERVICE

**Example of Rio Grande at Laredo AHPS page**
***Blue line: observed stage***
***Green line: forecast stage***
**Forecasts provided at least twice daily when river goes above caution stage. **
**Page also provides impact statements, tabular data, and other information.**
**Location pages also provide access to text products (FLW, FLS, RVS).**

## Summary

**Soil moisture continues to decrease, is expected to remain near to above normal through at least the early part of summer. **
**Reservoir levels have improved over the last couple of years but remain below conservation levels.**
**Near normal rainfall most likely to occur May through July.**
**Above normal tropical storm/hurricane season expected for 2005.**
**Increase in rain gauge network over Webb County will hopefully improve Rio Grande River forecasts.**

## Weather Forecast Office – Austin/San Antonio

***Weather Forecast Office – Austin/San Antonio***

##  United States International Boundary and Water Commission – National Weather Service Annual Coordination Meeting

- May 4, 2005

**Mark Lenz**
- Senior Service Hydrologist
- National Weather Service
- Austin/San Antonio

## 2004 Rainfall

- Austin.............51.89” (1318.00mm)
- San Antonio.....45.33” (1151.38mm)

**2004 Rainfall**

## 2005 Rainfall

**January – March ==> Above Normal**
**April ==>** **Below Normal**
**San Antonio.....0.01”** **(Driest April on Record) (0.25mm)**
**Del Rio............0.09” (5****th**** Driest on Record) (2.28mm)**
**Austin..............0.91” (12****th**** Driest on Record) (23.11mm)**

## Amistad Reservoir

**Amistad Reservoir**

- As of May 3, 2005
- 1112.9 Feet / 339.2 Meters

## AHPS

-                  _**H**_ydrologic
-                                     _**P**_rediction
-                                                       _**S**_ervice

**                             **

- Questions??

- Thank You!

## Mark Lenz

***Senior Service Hydrologist***
***Austin/San Antonio Weather Forecast Office***
***830.629.0130  x228***
***Mark.Lenz@noaa.gov***
_***www.srh.weather.gov***_